FR2866729A1 - Multi-track audiovisual flow processing device, has administration module that synchronizes successive use of synchronized buffers by different active processes according to usage sequence determined by switching process - Google Patents

Abstract

The device has a self-controlled memory comprising an administration zone (4) dedicated to administration of the memory and a useful zone (5) for data processing, where the memory is reserved and dedicated to processing of multi-track flow. An administration module synchronizes successive use of synchronized buffers of each memory line by different active processes according to usage sequence determined by a switching process (27).

Description

SELF-ADMINISTERED SHARED VIRTUAL MEMORY DEVICE

SUITABLE TO MANAGE AT LEAST ONE MULTIPIST DATA STREAM
The invention relates to a self-administered shared virtual memory device.
A virtual memory is formed of an electronic RAM area associated with a microprocessor (s) on a motherboard of the central unit of a device. This virtual memory is organized in blocks of memory, which can be used dynamically by at least one application program and / or tasks or processes, in addition to one (s) zone (s) of electronic random access memory used by the operating system and the BIOS.
An application program is a program intended for a human user to perform functions (computer or other) chosen by him. Some application programs, especially in the audio-visual field, use or generate data streams, called multitrack streams, comprising a plurality of tracks read and / or written and / or modified in parallel. These data streams may require for their processing a large memory volume, be of very different formats, depending on the applications, and require synchronization between the tracks.
However, the need arises to have a device capable of managing such multitrack streams in large numbers, in parallel, without saturation of the RAM device.
For example, it would be useful to be able to read and / or transfer from one device to another and / or modify (filter, convert, transcode, encapsulate, extract ...) audiovisual multitrack streams of any format such as MPEG, MPEG2 , DV, audio, ... without requiring any specific configuration of the required virtual memory and without risk of saturation or blocking of this virtual memory. Other applications also require the processing of large multitrack parallel data streams. For example, in the oil industry, many seismic surveys are conducted which form data streams to be compared to model files.
Computer devices using shared virtual memory are already known.
To allocate virtual memory to an application program, use for example a function such as "malloc (size)" in C or "new [size]" language in C ++, which creates a virtual memory block accessible only by the process using this function. Libraries of known system functions such as "shmat" or "shmcreat" in C language to share a same area of virtual memory by several processes, which therefore target an initial address of known virtual memory. The synchronization is then performed by semaphores or mutual exclusion mechanisms ("mutex"), so that the different processes access the shared memory with an address shifted from the initial address. But these synchronization mechanisms assume, for each process, to know and take into account precisely the different tasks performed by the different processes, and the data formats used in virtual memory. In addition, the allocation of memory blocks is static and rigid.
EP-1 031 927 discloses a method for allocating blocks of a shared memory to different tasks (or processes), consisting of identifying and allocating blocks available in memory for each task via tokens and a single allocation table. This process is nevertheless independent of the application programs, which it does not take into account the specific constraints. Thus, it is particularly not suitable for processing multitrack data streams, such as audiovisual streams.
No known device can manage a shared virtual memory zone self-administered, and therefore self-adaptive, which allows its dynamic use for the processing of multitrack data streams of any formats not necessarily previously specified, and in any number.

The invention therefore aims to solve this general problem.
The invention aims more particularly at providing a device that is particularly suitable for processing audiovisual multitrack streams.
The invention also aims more particularly at providing a device in which the management of the virtual self-administered memory area is provided directly and completely automatically, since the application programs do not have to deal with the problems of memory addressing, of synchronization between functional processes, and parallel processing on various parts of this self-administered virtual memory area.
The invention also aims more particularly to provide a device for performing in parallel and simultaneously different processing (reading, writing, transfer, conversion, filtering, transcoding, compression, decompression, encapsulation, extraction ...).
The invention also aims to propose a device in which the management of the virtual memory area self-administered can absorb differences in write speeds or read media or devices.
To do this, the invention relates to a device comprising: - microprocessor means (s) and memory (s) live (s) able to run at least one operating system and at least one application program data processing, at least one virtual random access memory adapted to be used as working RAM for at least one application program, at least one of which is suitable for processing at least one digital data stream, said multi-track stream , comprising a plurality of tracks read and / or written and / or processed in parallel, characterized in that: a) it comprises means, said configuration means adapted to configure the device with:
a virtual memory zone, called self-administered memory, reserved and dedicated to the processing of multitrack streams, this self-administered memory comprising an administration zone dedicated to the administration of the self-administered memory, and a zone useful for the processing of data, a functional process, said process director, adapted to be loaded in RAM, and define and save in the administration area, at least one memory line for containing a list of buffers, called synchronized buffers, the area useful self-administered memory, a plurality of functional processes, so-called flow management processes, adapted to be loaded into RAM and, with at least one memory line, create and / or use at least one synchronized buffer in this memory line , to execute at least one task on data of a multitrack stream, then release this (these) synchronized buffer (s), b) the switchman is suitable for:
determining, according to predefined processing constraints for each multitrack stream to be processed, a sequence for using the synchronized buffers of at least one memory line by each flow management process, said active process, concerned with the processing of said stream multitrack, * transmit to each active process, data identifying the memory line (s) in which it must create and / or use at least one synchronized buffer, c) the device comprises a suitable administration module to synchronize the successive use of each synchronized buffer of each memory line by the active processes according to the usage sequence determined by the switcher process.
The invention thus makes it possible to process in parallel simultaneously (on the same time line) completely different multitrack streams, considered until now as totally incompatible with each other, for example a track in high definition video format without compression, and a track video having a high compression ratio format such as MPEG2 format. This result is achieved through the self-managed memory, the switcher process, the flow management processes, and the different memory lines, which allow the synchronization of data and the scheduling of the different flow management processes that can execute many different tasks on the data.
Advantageously and according to the invention, the administration module is linked (at compilation and execution) to the switcher process and to each flow management process, and brings together common management functions of the self-administered memory. According to the invention, this administration module is advantageously formed of a library of common functions linked (in the IT sense) to processes by object-oriented programming, for example as a dynamically linked library in C ++ language.
In addition to scheduling flow management processes for using synchronized buffers of a memory line, the administration module includes other common functions. In particular, advantageously and according to the invention, the administration module is adapted to determine, upon release by a flow management process of a synchronized buffer, the subsequent flow management process defined in the sequence of use. , and, failing that, to delete the synchronized buffer. Deleting the synchronized buffer makes the corresponding memory space available again for further processing. It should be noted that the synchronized buffers created on the same memory line do not necessarily correspond to contiguous fragments of the useful area of the self-administered memory.
Advantageously and according to the invention, each flow management process is adapted to process the data at each moment with a single synchronized buffer of a memory line, then to release this synchronized buffer at the end of processing, the use of different buffers synchronized memory line by each flow management process being performed successively, one after the other. As a result, the use of useful memory space is optimized, with several flow management processes being able to operate simultaneously on different synchronized buffers in a perfectly synchronized manner.
In addition, advantageously and according to the invention, the administration module comprises the following functions: - creation of the administration zone and the useful zone of the self-administered memory, - initialization of a memory line with a rate maximum filling of the useful area by this memory line, - creation of a synchronized buffer in a memory line, - release of a synchronized buffer, - access to a buffer synchronized by an active process, - determination of the subsequent active process on the sequence of using a synchronized buffer of a memory line, after releasing the latter by the preceding active process.
Furthermore, advantageously and according to the invention the switcher process is adapted to define, for each track of each multitrack stream to be processed, at least one memory line dedicated to the processing of this track. Furthermore, advantageously and according to the invention, the switcher process is adapted to define, for each track of each multitrack stream to be processed and for each flow management process processing data of this track, at least one source memory line providing data to be processed by the flow management process and / or at least one destination memory line receiving data processed by the flow management process.
In addition, advantageously and according to the invention the switcher process is adapted to define one and only one use sequence for all the synchronized buffers of the same memory line.
Furthermore, advantageously and according to the invention, the switcher process is adapted to transmit the sequence of use of each memory line to the first flow management process to be active on a synchronized memory line buffer, this flow management process being Creator of this synchronized buffer and defining and recording in the administration area data identifying this synchronized buffer and associating it with the memory line and the sequence of use.
Furthermore, advantageously and according to the invention, the switcher process is adapted to calculate, depending on the nature of each multitrack stream to be processed, a maximum size of the useful area of the self-administered memory that can be given to each memory line. In this way, the use of the useful area of the self-administered memory is optimized by the routing process according to the needs of each track of each multitrack stream, without risk of blocking. This maximum size is advantageously defined as a filling ratio, for example a percentage, of the useful area of the self-administered memory. It is saved in the administration area.
In addition, advantageously and according to the invention the flow management processes are distinct, each of them performing at least one task of its own. On the contrary, there is nothing to prevent several identical versions of one or more flow management processes from being active simultaneously, in particular to perform similar tasks in parallel.
In one embodiment of the invention that is advantageous for many applications of the device, the device comprises at least one application program, called a launcher module, adapted to load in the RAM the different processes and modules allowing the configuration and operation of the memory. self-administered including: - the switcher process, - each flow management process that can be used for the processing of multitrack streams, - the administration module, - a dynamic windowing module on a display screen of the device , adapted to form a human / machine interface allowing a user to define each multitrack stream to be processed from source data of various origins. In this variant, it is the loading in memory of the launcher module, on command of a human user, who can configure the device with self-administered memory, flow management processes, and the process according to the invention. The windowing module is an application program that enables the user to use the device according to the invention thus configured in a simple and user-friendly manner, in particular by clicking / dragging commands of source data files intended to constitute the ) multitrack stream (s).
In another variant, which can also be combined with the previous one, the device according to the invention can be configured beforehand, for example as soon as it is started, and operate more or less automatically, in particular as a slave within a complex architecture (for example within a network), or on command of an automatic control application program to execute certain tasks according to predetermined events (for example, to assemble, convert and record on a recording unit several tracks read from various external sources). In this variant, the dynamic windowing module is not essential.
Advantageously and according to the invention, the device comprises: at least one flow management process, referred to as a loading process, capable of writing data, in particular data from a reading unit, in a useful area of the memory self-administered, - at least one flow management process, said process capable of reading data -in particular data intended for a receiving unit such as a recording device, a display screen ...- since the useful area of the self-administered memory.
A reading unit may be a device of the device according to the invention, another device or any device capable of transmitting data to the device according to the invention.
Similarly, a receiving unit may be a device of the device according to the invention, for example a recording device, another device, or any device capable of receiving data transmitted by the device according to the invention.
Furthermore, advantageously and according to the invention, the flow management processes are adapted to be able to be loaded into a RAM area separate from the self-administered memory. Similarly, the sender process is adapted to be loaded into a RAM area separate from the self-administered memory.
In addition, advantageously and according to the invention, the switcher process is adapted to, in a first analysis step, analyze the characteristics of each multitrack stream to be processed and the processing constraints of each multitrack stream, so as to define the data representing the memory lines, and data representing each sequence of use of the synchronized buffers of each memory line for the processing of this multitrack stream, then in a second subsequent processing step, start the processing of the multitrack stream according to said data previously defined during the analysis step.
The predefined constraints specific to each stream may be predefined by programming the switcher process and / or recording parameters in a mass memory of the device and / or by data, called metadata, associated with the stream -especially in a header- and read by the switcher process and / or provided by the application program. These constraints include for example the number of tracks; synchronization data between tracks; the duration of each track; the rate of data transfer from / to a reading unit / receiver unit; the format of the data on each track; the mode of data compression; the nature of the treatment to be performed on each track ....
Advantageously, in a device according to the invention, the size of the self-administered memory is defined by the configuration means to a predetermined fixed value-in particular between 20% and 80% of that of the virtual memory, typically from order of 128 megabytes to 15 gigabytes with current memories. Similarly, advantageously and according to the invention, the size of the administration zone is defined by the configuration means to a predetermined fixed value-in particular an absolute fixed value, for example of the order of 1 megabyte. The size of the administration area is much smaller than that of the useful area of the self-administered memory. In addition, advantageously and according to the invention, the self-administered memory is defined by the switcher process when it is loaded into random access memory.
Furthermore, advantageously and according to the invention, in the administration area each element, said administration element, contains an address of a previous element and an address of a next element.
Advantageously and according to the invention, the administration zone comprises during the processing step: a list of available self-administered memory fragments, a list of active memory lines (that is to say defined by the switcher process), - a list of synchronized buffers of the useful area of the self-administered memory to be used by the active memory lines, and a list of the different active processes that should use these synchronized buffers of self-administered memory.
Advantageously and according to the invention, the configuration means are adapted to allow the processing of multitrack streams which are audiovisual streams, in particular having tracks whose format is chosen from: high definition television (HDTV) formats, standard definition television (SDTV) formats, - digital cinema formats, - compressed video formats (MPEG2, MPEG4, DV ...), - uncompressed audio formats, - compressed audio formats, - audio formats, multi-track encapsulation (Quicktime, AVI ...), - image formats, - raw audiovisual data formats.
The invention extends to a recording medium that can be read by a reading unit associated with a digital processing device, this recording medium comprising a computer program adapted to be able to form configuration means. a device according to the invention, when installed, and executed on this device.
The invention extends to a multitrack flow processing method using a device according to the invention.
The invention also extends to a device; to a recording medium, and to a process characterized in combination by all or some of the features mentioned above or hereinafter.
Other objects, features and advantages of the invention will appear on reading the following description given solely by way of non-limiting example, which refers to the appended figures in which: FIG. 1 is a diagram representing the organization of a RAM of a device according to the invention, - Figure 2 is a diagram of an example of a device environment that can be advantageously operated with a device according to the invention, - Figure 3 is a diagram of an example of a window of a man / machine interface activated by a launcher module of a device according to the invention, - Figure 4 is a diagram illustrating an example of a functional computer architecture of a device according to the invention, FIG. 5 is a flowchart illustrating an exemplary algorithm of a switching process of a device according to the invention; FIG. 6 is a flowchart illustrating an example of an algorithm of a management process of FIG. FIG. 7 is a diagram illustrating the general architecture of the requests and states of the flow management processes of a device according to the invention, FIG. 8 is a diagram illustrating the general architecture of the requests and states of the flow management processes of a device according to the invention; an example of a timing diagram of two multitrack streams, to be processed successively; FIG. 9 is a diagram illustrating the organization of the operation of the self-administered memory of a device according to the invention for the processing of the flows of FIG. .
A device 1 according to the invention is a digital data processing device which can, from the point of view of its structural architecture, present all known possible embodiments. It may be a microcomputer comprising a motherboard with microprocessor (s) and associated random access memory (RAM); one or more memory module and / or peripheral connection buses (in particular a man / machine interface comprising a keyboard, a pointing device, a display screen); and mass memories such as a hard disk and / or readers / recorders of removable mass storage media. It may also be a network architecture comprising several machines and / or several machine parts interconnected.In any event, the device according to the invention is adapted to form at least one central unit allowing the execution of at least one operating system (in particular of the LINUX, UNIX, WINDOWS, ... type) and one or more application programs for data processing.
The device according to the invention further comprises at least one virtual memory 2 adapted to be used as working memory for application programs.
A virtual memory is in fact a RAM area managed centrally by at least one operating system module, and which can be made available to at least one application program to enable it to perform specific tasks.
FIG. 1 shows an example of virtual random access memory 2. This virtual memory 2 can be a portion of electronic random access memory associated with a microprocessor on a computer motherboard. It should be noted that the invention applies equally well to the implementation of such a virtual memory with other embodiments of RAM, for example an associated random access memory via a bus to a microprocessor. The production technology of this RAM is actually of importance in the context of the invention since the capabilities and access speeds and other characteristics of the hardware memory implementing this RAM are compatible with the applications that are made, especially in terms of processing time. In particular, it should be noted that for the processing of audiovisual multitrack streams, especially for their reading, the processing times in RAM must be sufficiently low to avoid any interruption in the playback of the audiovisual stream or any hashing or jerking phenomenon.
In a device according to the invention, a predetermined portion of the virtual memory 2 can be reserved and dedicated to processing multitrack streams. This specific area, called self-administered memory 3, can be defined in advance, for example by configuration of the user, either as a fixed value or by a value corresponding to a percentage of the virtual memory 2 total or RAM 1 total.
In the example shown in FIG. 1, the virtual memory 2 has a capacity of 512 megabytes, and the self-administered memory 3 has a capacity of 256 megabytes.
In addition, the self-administered memory 3 comprises two distinct zones, namely a zone, called the administration zone 4, dedicated to the administration of the self-administered memory 3 and in which data allowing the administration (organization, synchronization, defragmentation ...) of the self-administered memory 3 can be recorded; and a zone, called the useful zone 5, serving as a working memory for the processing of digital data streams, called multitrack streams, comprising a plurality of tracks read and / or written and / or processed in parallel. The size of the useful zone 5 is very much greater than that of the administration zone. The administrative data is not data to be processed by the device, such as multitrack stream data).
The tracks of the multitrack stream are for example a video track, an audio track, etc. In a multitrack stream at the input and / or the output, the tracks can be transmitted in a format multiplexed on a single line and / or compressed, for example MPEG2, DV .... But the processing of a multitrack stream can include at least one task or series of tasks (playback, recording, conversion, transcoding, filtering, compression, decompression, encapsulation, extraction of an encapsulated format, ...) to be performed separately on several tracks (the number of which can be very important).
As represented in FIG. 2, the device 1 according to the invention can be used for the processing of data streams originating from and / or intended for various peripherals of formats which are normally incompatible with one another. In the example represented in FIG. 2, there are provided cameras (for example digital typecinema, digital video or digital video camera, etc.) that can provide video data via HDSDI, SDI, "Firewire" type interfaces (called also "I-Link" or IEEE1394), or Ethernet. In the example, there is shown a digital cinema camera 6a and a DV camcorder 6b. There is also provided a video recorder 7 or other reader / recorder device which can acquire and / or provide video data via HDSDI, SDI, "Firewire" type interfaces or a local network, for example of the Ethernet type. It can also be provided a mass memory such as a disk unit 9, for example of RAID type providing and / or receiving video data, a VGA type display screen or a video monitor 10 receiving video data by an interface of type HDSDI, SDI or analog, and a link to a network 11 by an Ethernet type interface or shared storage network "SAN". In this example, the device 1 according to the invention constitutes a video server.
Of course, this illustration is only an example and any other link providing or receiving multitrack data can be provided, for example a television broadcast receiver (over the air, satellite or cable, ...).
The device according to the invention comprises at least one application program, called launcher module, adapted to load in RAM and start the execution of configuration means of the device according to the invention. This launcher module in particular launches a dynamic windowing module which produces, on a display screen of the device, a window 26 such as that shown in FIG. 3, adapted to form a human / machine interface 26 enabling a user to define each multitrack stream to be processed from source data of various origins.In the example shown in FIG. 3, the window 26 comprises a title bar 12, a menu bar 13, a video display window 14 associated with a zone 15 of control / display of playback / recording information (rewind, rewind, play, pause, stop, fast forward, feed, counter, ...). There is also provided a navigation window 16 including a display area 17 of the file tree and a display area 18 of thumbnails or icons representing files.
The window 26 further comprises a mounting window 19 comprising a command or action zone 20, a zone 21 for chronographic representation of the multitrack streams to be processed used in the case of an edition, an area 22 for filtering tools. which can be actuated by the user and a complementary zone 23 for displaying / entering specific commands. It can also be advantageously provided a zone (not shown in the example) for managing the acquisition of multitrack streams.
With such a window 26, the user can for example simply select a file in the navigation area 16 and move it to the chronographic display area 21, which will have the effect of taking into account the multitrack stream associated with this file in its processing by the self-administered memory 3. Thanks to the invention, it is possible in particular to associate on the same timing diagram and simultaneously in a synchronized manner different multitrack streams of completely different, normally incompatible formats, and in particular high definition formats, formats in standard definition, compressed or uncompressed formats, encapsulation formats (Quicktime, AVI, ...).
FIG. 4 represents an exemplary computer architecture corresponding to the means for configuring the self-administered memory 3 in a device according to the invention. This architecture comprises the man / machine interface 26 represented in FIG.
This human / machine interface 26 communicates with a functional process, called the switcher process 27, which is loaded into RAM 1 and preferably executed on the same machine as that on which the self-administered memory 3 is managed. This switcher process 27 is a functional process, i.e., a low-level server-type process in the operating system that is not directly visible or accessible to the user.
The configuration means according to the invention furthermore comprise other functional processes, called flow management processes, the number of which is not limited, each of them being adapted to be able to be loaded into RAM 1 and to realize at least one task on data of a multitrack stream. Many flow management processes can be developed according to the functions to be performed for the application to consider the device according to the invention.
Preferably, each flow management process is adapted to perform a single specific task, or a series of tasks corresponding to a single processing function on a track of a multitrack stream, for example, a read, a record, a transfer. to a device such as a display screen, filtering, transcoding, compression, decompression, encapsulation, extraction of an encapsulated format, etc.
It should be noted, however, that the human / machine interface 26 communicates directly and only with the switcher process 27, and in no way with the flow management processes. Therefore, whatever the function required by the application program controlled by the man / machine interface 26, this function is necessarily addressed to the sender process 27 and processed and analyzed by the latter.
In the nonlimiting example shown in FIG. 4, there is provided, as a flow management process, a process 28 for loading data into the useful area 5 of the self-administered memory 3, a process 29 for recording data. data from the useful area 5 of the self-administered memory 3, a process 30 of filtering data read in the useful area 5 of the self-administered memory 3 and re-written after filtering in the useful area 5 of the self-administered memory 3 , and a visualization device control process 31. It should be noted that the different flow management processes do not communicate with each other directly, but only communicate with the switcher process 27. Communication between the dynamic man-machine interface window 26 and the switcher process 27 is effected by two dedicated communication links (for example of the "SOCKET" type), namely a communication link of the command / acknowledgment CMD / ACK 24 type, and a monitoring link 25 making it possible to transmit the statuses, the time codes and any errors between the switcher process 27 and the dynamic windowing module 26.
Each flow management process 28, 29, 30, 31 is configured by the switcher process 27. Moreover, the different flow management processes 28 to 31 only exchange between them data corresponding to the content of the multitrack streams, via the useful area 5 of the self-administered memory 3.
Each flow management process 28 to 31 is connected to the switcher process 27 by two communication links (for example of the "SOCKET" type), namely a control / acknowledgment link (CMD / ACK) and a monitoring link of possible errors identified by the corresponding flow management process 28 to 31.
There is also provided a common library 32 of computer operations that the flow management processes 28 to 31, and the switcher process 27 use to perform common commands or tasks via writes / reads in memory. This library 32 forms a module, said administration module 32, programmatically linked to each process 27, 28 to 31.11 It should be noted that the self-administered memory 3 with the flow management processes 28 to 31 and the switcher process 27 and the administration module 32 can operate entirely autonomously, without requiring the execution of a dynamic windowing, or more generally of a graphical user interface such as 26.
The different flow management processes 28 to 31 are preferably similar in their operation and their architecture. This common general architecture is represented for example in FIG.
The REQ_ISALIVE service allows the human / machine interface module 26 to know if the different flow management processes are loaded and active or not.
The REQ_INIT service performs the initialization of the flow and place management process in the "INIT" state represented in FIG. 7. It is at the reception of this service that all the flow management processes will be configured before launching. an action on data to be processed. Each flow management process also has a REQ_CHANGECONF service that allows the switcher process 27 to change the specific configuration of this flow management process.
REQ_PROCESS generically designates all the actions performed on each multitrack stream by a flow management process which is then in the "PROCESS" state represented in FIG. 7.
The REQ_STOP request places the flow management process in the initialized state. The REQ _RESET request allows the flow management process to return to a stable state "READY".
The library 32 forming the administration module comprises various common functions that can be used by the processes, and in particular: a function for creating the administration zone 4 and the useful area 5 of the self-administered memory, consisting in to reserve the corresponding RAM areas with their corresponding memory addresses, - an initialization function in the administration zone 4 of a memory line (on command of the switching process 27), with a maximum filling rate (calculated by the switcher process 27), the useful area 5 by this memory line, - a function for creating a buffer synchronized in a memory line, (by a flow management process creating such a synchronized buffer) with its memory size , its number, its address, its sequence of use (list of the different processes of management of active flows having to access successively this buffer, as determined by the pro 27), and a field storing its current state, - a function of accessing a synchronized buffer of a memory line by an active flow management process, - a function of releasing a synchronized buffer after use by a flow management process, making this synchronized buffer available for the subsequent flow management process, or delete this synchronized buffer if it is the last active flow management process to take effect on this synchronized buffer, - A synchronization function of determining, after release of a buffer synchronized by an active process, what is the subsequent active process to intervene on this synchronized buffer, from the sequence of use of this synchronized buffer.
This library 32 may be formed of classes programmed for example in C ++ language.
The launcher module loads in RAM, in addition to the man / machine interface 26, the switcher process 27, each flow management process 28 to 31, and the library 32 (administration module), these processes 27 to 31, between they and the library 32 being linked.
Fig. 5 shows an operating flowchart of the switcher process 27.
Step 50 represents the initialization of the switcher process 27 and its loading in memory, for example under the effect of launching the launcher module. In the subsequent step 51, the switcher process 27 creates the self-administered memory 3. It creates a connection with each flow management process 28 to 31. When the user executes a command on the window 26, the switcher process 27 actually receives a multitrack flow sequence (s) in the form of a conventionally designated chronogram. "list of editions". This reception is shown schematically by step 52 figure 5.
It then executes, during step 53, the analysis of this list of editions and opens a loop on the different editions, that is to say on the different tracks to be treated.
The switcher process 27 records (step 54), in the administration area of the self-administered memory 3, one or more lines of memory, including in general at least one source memory line and / or at least one destination memory line. The switcher process 27 creates at least one memory line for each track (source or destination) to be processed. It should be noted that the same memory line can act as source and destination for the data to be processed.
For example, it creates a memory line for receiving a source video track and a source memory line for receiving an audio track that must be processed in parallel, and / or one or more destination memory line (s) for receiving the processing result. through the active flow management process.
This analysis step 53 enables the switcher process 27 to define the number of memory lines, the maximum memory size of each memory line, and the sequence of use of the buffers synchronized on each memory line, and this according to the predefined constraints. by the application program that provides the multitrack stream to be processed to the switcher process 27. In the example, this application program consists of the man / machine interface 26. The analysis step 53 is in particular launched when the user places a file in the chronographic display area 21 by means of its pointer device, which has the effect of providing the switcher process 27 with requests and parameters corresponding to the multitrack stream to be processed. Upon receipt of such a request When editing a multitrack stream, the routing process 27 determines in a first place whether the processing to be performed consists of an edition or, conversely, an acquisition.
Case of an edition:
According to the parameters transmitted by the application program 26, the switcher process 27 determines whether the edition must be filtered and / or displayed and / or recorded and determines the sequence of use of the synchronized buffers for each memory line to be created, corresponding to reality to the sequence of intervention of the different flow management processes that must be active on each track of the multitrack flow.
The parameters taken into account are: - a file "editions list" (edl), - a file "list of files" (edl file), - a file "list of filters" (edl of filter).
For each edition, that is to say each track, of the list of editions, the switcher process 27 determines the format of the data, that is to say in particular the audio / video standard in which they are recorded, and determines the size of the edition (i.e., of the track) relative to the maximum size of the different editions of the sequence, to determine the percentage of useful area of RAM that can be allocated to each memory line corresponding to each track.
The switcher process 27 then creates a source memory line for each audio track and a source memory line for each video track, and calculates and formats the parameters for the loading process, namely the identification of the different memory lines used and the corresponding usage sequences.
The switcher process 27 then determines whether each edition, i.e. each track, should be filtered or not. If so, the switcher process 27 extracts from the filter file sent in parameters the filter or filters relating to the track to be filtered, and checks the number of input / output, then creates as many memory lines as there are output for the filter (s) to be applied. The switcher process 27 then prepares and formats the parameters for the filtering process, namely the identification of the different audio and video source memory lines and the different destination memory lines of the track.
The switcher process 27 then examines whether or not the track should be viewed. If so, and if the track has also been filtered, the switcher process 27 uses the destination memory lines identified for the filtering process. If the track is to be viewed without filtering, the switcher process 27 sends the previously created audio and video source memory lines to the visualization process. It should be noted that in this case, the source memory lines also act as destination memory lines. The switcher process 27 then calculates and formats the parameters for the visualization process (memory lines and usage sequences).
The switcher process 27 then determines whether or not the edit stream should be recorded. If so, and if the stream has been filtered, the switcher process 27 uses destination memory lines of the filtering process. If the stream is to be recorded without filtering, the switcher process 27 sends the audio and video source memory lines to the registration process. Again, it calculates and formats parameters for the registration process (memory lines and usage sequences).
Case of an acquisition:
Based on the parameters received from the application program, the switcher process 27 determines whether the acquisition is viewed and recorded and calculates the corresponding synchronized buffer usage sequence.
The parameters are: - a file "list of acquisition editions" (edl acquisition), - a file "list of files" (edl file).
For each edition of the edition list transmitted to the switcher process 27, the latter determines the format of the data (standard audio / video), and calculates the size of the acquisition edition relative to the maximum size of the different tracks of each multi-track stream of the sequence to be acquired, so as to determine the percentage of useful areas of the self-administered memory that can be used by each memory line.
In the case where the switcher process 27 then detects the presence of audio tracks in the list of acquisition editions, it creates an acquisition memory line for each corresponding audio track. Similarly, when the switcher process 27 detects the presence of video tracks in the list of acquisition editions, it creates an acquisition memory line for each corresponding video track.
The switcher process 27 then determines and formats the parameters for the acquisition process, including the identification of the different memory lines and their sequence of use.
The switcher process 27 then determines whether the editing is to be viewed or not. If so, it prepares the corresponding parameters (acquisition memory lines) for the visualization process. Then, the switcher process 27 determines and formats the parameters for the registration process.
The analysis step 53 and the step 54 for creating the memory lines described above are only non-limiting examples and many other forms of analysis may be provided, depending on the applications of the device according to the invention. .
The next step 55 is to open a loop on the different flow management processes 28 to 31 loaded into memory. For each of these processes, it is performed in step 56 a test to determine if this flow management process 28 to 31 may be concerned by the track to be treated. If so, the switcher process 57 sends the memory lines and the synchronization information (usage sequence) corresponding to the first flow management process concerned, in step 57. If not, the process loops back to pass to the next flow management process. After step 57, a test 58 is executed to complete the loop, i.e., to know if this was the last flow management process in the usage sequence. If this is not the case, we proceed to the next flow management process. If this is the case, we run a test 59 to find out if the treated track was the last one. If this is not the case, it loops back to step 53 to rerun steps 54 to 58 on the next track. If this was the last track, the first phase of analysis of the multitrack flow sequence (s) to be processed is completed, and we proceed to a subsequent phase of execution comprising first a step 60 of initialization of the switcher process 27, then reception during step 61 of a command from the user, that is to say from the application program controlled by the user (human / machine interface 26), and then, in step 62, an action is sent to each flow management process 28 to 31 to trigger the operation of these flow management processes, and this in a synchronized manner with each other.
Figure 6 shows the flowchart of a flow management process controlled by the sender process 27. In Figures 5 and 6, the links between the two flowcharts are represented by the letters A and B.
Step 63 corresponds to the launch of the flow management process, followed by the step 64 of attaching this flow management process to the self-administered memory 3, that is to say to the state " READY "shown in FIG.
In the subsequent step 65, the flow management process may receive a list of edits (a multitrack flow sequence) sent to it by the switcher process 27 at the end of step 57 of this switcher process. 27. If the flow management process then receives an action at step 66 from the switcher process 27 (following step 62 of sending action of this switcher process 27), the management process flow opens a step 67 opening loop which allows to browse each track in the list each corresponding to a memory line. Following this step 67, it performs a test 68 to determine whether the requested action and the function it performs corresponds or not to the creation of one or more buffer (s) synchronized (s) in the useful area 5 3.Done in the negative, the flow management process executes a synchronized buffer synchronization step 69 of the self-administered memory 3. It then performs a test 70 to determine whether this synchronized buffer is or is not available on the source memory line.
It should be noted that the synchronized buffer on which the flow management process is positioned is determined in advance in the memory line by the switcher process 27, and this data is known from the flow management process.
As long as the synchronized buffer is not available as determined by test 70, the flow management process returns to step 69 waiting. When the synchronized buffer becomes available, the flow management process executes the subsequent step 71 of processing the data in this synchronized buffer.
Also, if the test 68 determines that the flow management process should create a synchronized buffer, then step 72 of creating this synchronized buffer is executed, and then the process proceeds to step 71 of data processing in the synchronized buffer. synchronized buffer thus created.
The flow management process creates a synchronized buffer when it is the first flow management process to occur on a memory line to be processed. After executing the data processing step 71, the flow management process releases the synchronized buffer in step 73 to make it available for the flow management process to then operate on that synchronized buffer. After this step 73 of release of the synchronized buffer, the flow management process ends the loop of the different streams of the list through the test 74 which, after having processed all the tracks of the list, executes a step 75 of end of processing this list of editions.
The common library 32 makes it possible to define different administration elements which are actually lists, since each administration element contains a reference to the following and previous elements.
A memory fragment type administration element is further defined by its start offset with respect to the base address of the useful area 5 of the self-administered memory 3, its end offset with respect to the address. of this useful area 5 of the self-administered memory 3 and its size.
An element of type memory line or "TRACK" is further defined by an identifier, a list of synchronized buffers associated with it and by its size.
A memory buffer type administration element or "BUFFER" is further defined by its identifier, its address in memory (offset with respect to the start address of the useful area 5 of the memory), its size, a sequence of use (or transition table), and a variable representing its state.
The administration zone 4 is divided into administration buffers where the administration elements (memory lines, memory buffers or free memory fragments) will be defined.
When requesting the creation of a memory line or a memory buffer, the administration module 32 converts a free administration element into a memory line or memory buffer type element.
In the case of a conversion to a memory line type element, the switcher process 27 defines the usage sequence according to the processing constraints of the multitrack stream and in particular according to the different flow management processes that will be necessary for this processing.
In the case of a conversion of an element into a memory buffer, the administration module 32 retrieves a fragment of the free useful area 5 from the list of free memory fragments, and this according to the desired size for this stamp. Three cases can occur:
1) If the free memory fragment is smaller than the size of the desired memory buffer, the administration module will retrieve the next free memory fragment and restart the test. If it does not have a free memory fragment, an error is returned to the creative flow management process (the process then makes several successive requests waiting for the release of a zone by another process).
2) If the free memory fragment has the same size as the desired buffer size, assigning the fragment start value to the address value of the memory buffer, and deleting the free memory fragment from the free memory fragment list in the administration area 4.
3) If, on the other hand, the memory fragment is larger than the size of the desired memory buffer, the fragment start value is assigned to the address value of the buffer and the free memory fragment is reduced to the size allocated to the buffer.
Then, the state of the memory buffer is initialized to the value corresponding to a number identifying the active flow management process on this buffer.
When releasing a buffer synchronized by a flow management process, the state will change according to the usage sequence defined for this synchronized buffer (either return to the initial state or change to the next state , the latter case causing the availability of the synchronized buffer for the subsequent flow management process, either deleting the buffer in the case where it would be the last flow management process in the usage sequence).
If the release of the synchronized buffer involves its deletion, the administration module 32 converts the latter to a free memory fragment, and is added after the list of free memory fragments in the administration area 4. Next , it defragments the useful area of the memory by verifying that the released synchronized buffer is or is not adjacent to one or two free memory fragments.
When requesting access from a synchronized buffer by a flow management process, the following checks are made before giving access to the synchronized buffers: - does the memory line exist? - does the synchronized buffer exist? - is the synchronized buffer available for the flow management process (checking its current state)? If the synchronized buffer is available for this flow management process, the synchronized buffer address is returned to the flow management process that can use it. Otherwise, a code indicates the status of the synchronized buffer.
The flow management process has the ability to request access to a memory buffer asynchronously (useful for a verification process), that is, it can retrieve a memory buffer regardless of the state of the last.
It should be noted that such a self-administered memory management method implemented in a device according to the invention can be implemented in any computer language that supports dynamic memory allocation and shared memory management. It should also be noted that the descriptive data contained in a memory buffer may vary. For example, the identifiers (memory buffer or memory line) consisting of integers can be replaced by character strings. FIGS. 8 and 9 illustrate an example of a particular application. It should be noted that this example does not correspond to not strictly to the example of implementation shown in FIG. 4. In FIG. 8, an example of a chronogram of two successive audiovisual streams is represented, namely a sequence in the MPEG2 format that lasts 3 seconds and which comprises a video track VI and an audio track A1, followed by a DV sequence, which also lasts 3 seconds, also comprising a video track VI and an audio track A1. FIG. 9 schematically represents the processing of these streams by the self-administered memory 3 in accordance with FIG. 'invention. The editing list 90 is provided to the switcher process 27. In the example shown, the following flow management processes are provided: a loading process PGF1, a video viewing process PGF4, a listening audio process PGF5, a PGF2 MPEG 2 decompression process, and a PFG3 decompression process DV.
In the example shown, each flow management process uses at least one source memory line and at least one destination memory line. The LMO memory line as a source means that the flow management process is synchronized buffer creator (and first participant of the usage sequence) and does not receive data from a memory line (eg loading process) . Similarly, the LMO memory line as a destination means that the flow management process is the last participant in the usage sequence on a synchronized buffer.
The switcher process 27 defines in the administration zone 4 with the aid of the library 32, six memory lines, LM1, LM2, LM3, LM4, LM5, LM6 with, for each of them, its maximum size and its start address. For example, the maximum size for the memory line LM1 and for the memory line LM4 is 10% of the useful area 5 of the self-administered memory 3. And the maximum size of the memory lines LM2, LM3, LM5 and LM6 is 20% of the useful area 4 of the self-administered memory 3.
Each buffer-flow management process synchronized to a destination memory line also defines synchronized buffers such as TM1, TM2 ..., and records in the administration area 4 their size, number, address, and their sequence. use, and their current state, all using the library 32.
There is shown in the useful area 5 of the self-administered memory 3 the different memory lines LM1 to LM6 and the nature of the data that are processed there. The synchronization data that is addressed by the sender process 27 to each of the flow management processes that identify the source and destination memory lines and the synchronization information (usage sequences and / or synchronized buffer identification) are also shown. .
In the example shown, the switcher process 27 provides to the first flow management process (PGF1) which is the loading process, the information 95 including the number of the source memory line, which in the example is LMO, and the number of the destination memory line and the sequence of use of the synchronized buffers of this destination memory line. For the first edition list (MPEG2 sequence), the destination memory line is LM1 and the usage sequence is 1.2, which means that the flow management processes PGF1 and PGF2, successively, will have to intervene successively on the data from the memory line LM1 for the processing of this stream. For the second edition list (DV sequence), the source memory line is LMO, the destination memory line is LM4 and the usage sequence is 1.3. which means that the processes PGF1 and PGF3 will intervene successively.
The loading process PGF1 is the creator of synchronized buffers since it has to load the data of the source memory line into the useful area 5 of the memory. The loading PGF1 process therefore creates the necessary synchronized buffers. Typically, in the example shown, thirty synchronized buffers per second of the stream must be created. Thus, the loading process PGF1 uses successively ninety synchronized buffers TM1, TM2, ..., TM90 for the MPEG2 sequence on the destination memory line LM1. To do this, he creates a first TM1 synchronized buffer, loads data from the MPEG2 sequence, and then releases the TM1 buffer. The administration module 32 then allows the subsequent active flow management process to intervene, that is to say the PGF2 process which performs MPEG2 decompression. The loading process repeats these operations successively on the ninety synchronized buffers. TM1 to TM90.
Previously, the switcher process 27 provided the information 96 to the subsequent flow management process PGF2. In this way, this process PGF2 knows that it must intervene on a source memory line LM1, and on the destination memory lines LM2 with the sequence of use 2, 4 (PGF2 then PGF4) and LM3 with the sequence of use 2, 5 (PGF2 then PGF5), for synchronized buffers starting at synchronized buffer TM1 up to synchronized buffer TM90. Thus, this example shows that, thanks to the invention, several flow management processes are active simultaneously on different synchronized buffers, and this, in a perfectly synchronized manner.
The process PGF2 can thus use the memory line LM2 for the video track coming from the stream MPEG2 and the memory line LM3 for the audio track coming from the stream MPEG2. It successively loads and releases the synchronized buffers of these two memory lines with the appropriate data, as described above for the PGF1 process. The administration module 32 then makes it possible to use the buffers synchronized by the video management flow management process PGF4 of the memory line LM2 as the successive release of these synchronized buffers. the same way, the successive use of the buffers of the LM3 memory line by the audio listening process PGF5.
Again, the switcher process 27 previously provided the information 97 and 98 respectively to these PGF4, PGF5 processes. In this way, these two processes know that the source memory lines LM2 and LM3 must be processed, and that the destination memory line is LMO, which means that these processes PGF4, PGF5 are the last speakers on the corresponding usage sequence. to the MPEG2 stream.
The device according to the invention thus makes it possible in the given example to read simultaneously, from an MPEG2 stream, an audio track and a video track in a perfectly synchronized manner.
In addition, the PFG1 process loads data into memory while the PGF2 and PGF3 processes read and decompress data from the memory. It is indeed an advantage of the invention to allow several processes to use the memory in writing and / or reading simultaneously.
The same type of operation takes place for the processing of the second stream in DV format. As it is loaded into the synchronized buffers of the LM4 memory line successively, the usage sequence allows the activation of the DV decompression flow management process PGF3. The latter receives the data from each synchronized buffer of the memory line LM4 in the DV format and decompresses and loads this uncompressed data into the synchronized buffers successively of the two memory lines LM5 with the usage sequence 3, 4 (PGF3 then PGF4) and LM6 with the sequence of use 3, 5 (PGF3 then PGF5) video, respectively audio.The switcher process 27 had communicated the information 99 to the flow management process PGF3 to indicate the identification of the source and destination memory lines, the sequences as well as the synchronized start and end buffer numbers (TM91 and TM180).
It should be noted that, with a device according to the invention, the synchronized buffers TM1 to TM90 or TM91 to TM180 created on the same memory line do not necessarily correspond to contiguous spaces in the useful area 5 of the self-administered memory . This results in a much more flexible and effective management of this useful area 5, whose capabilities are greatly improved over previous devices, in which such a use of disjoint buffers for the same process and / or for the treatment of the same data flow is not possible. But, the memory lines represent an abstraction of attachment and continuation of the synchronized buffers.
As can be seen, the different flow management processes receive from the switcher process 27, the entirety of the synchronization information and do not communicate with each other. They are synchronized from this information, and by the administration module 32. Only the PGF1, PGF2, PGF3 flow management processes that create synchronized buffers in the memory lines receive the corresponding usage sequences, and record them in the administration area 4 with the memory lines and the identifier of the corresponding synchronized buffers.
Of course, the example shown in Figures 8 and 9 is not limiting and many other possibilities are offered. For example, two video sequences in uncompressed format, can be read simultaneously on the same screen, separated into two distinct parts with the device according to the invention.
Thus, it suffices to provide a track of the type, for example FI, performing filtering consisting in embedding one image in another and applying a flow management process corresponding to this incrustation simultaneously on the two sequences read in parallel. The switcher process 27 may define three memory lines, namely a source memory line for each of the video sequences to be read, and a third destination memory line to receive the result of the overlay that will be provided to the video viewing process. Many other examples are possible.

Claims (14)

1 / - Device comprising: - microprocessor means (s) and memory (s) live (s) capable of executing at least one operating system and at least one application program for data processing, - at least one memory virtual voucher, adapted to be used as working memory for at least one application program, at least one of which is adapted for processing at least one digital data stream, said multitrack stream, comprising a plurality tracks read and / or written and / or processed in parallel, characterized in that: a) it comprises means, said configuration means adapted to configure the device with: a virtual memory area, said self-administered memory (3) , reserved and dedicated to the treatment of multitrack streams, this self-administered memory comprising an administration zone (4) dedicated to the administration of the self-administered memory, and a useful area (5) for the tr a data processing, a functional process, said switcher process (27), adapted to be loaded in RAM, and define and record in the administration area (4), at least one memory line for holding a list of buffers said synchronized buffers, the useful area (5) of the self-administered memory, a plurality of functional processes, said flow management processes (28-31; PGF1-PGF5), adapted to be loaded into RAM and, with at least one memory line, to create and / or use at least one synchronized buffer in this memory line, to execute at least one task on data of a stream multi-track, then release this synchronized buffer, b) the routing processor (27) is adapted to: * determine, according to predefined processing constraints for each multitrack stream to be processed, a sequence of use of the synchronized buffers of at least one line memory by each flow management process, said active process, concerned with the processing of said multitrack stream, * transmit to each active process, the line (s) memory (s) in which (he) it must create and / or use synchronized buffers, c) it comprises an administration module (32) adapted to synchronize the successive use of the synchronized buffers of each memory line by the act processes ifs according to the sequence of use determined by the switcher process (27). 2 / - Device according to claim 1, characterized in that the administration module (32) is related to the switcher process (27) and to each flow management process, and brings together common functions of management of the memory. administered (3). 3 / - Device according to one of claims 1 or 2, characterized in that the administration module (32) is adapted to determine, upon release by a flow management process of a synchronized buffer, the process subsequent flow management defined in the usage sequence, and failing this, to delete the synchronized buffer. 4 / - Device according to one of claims 1 to 3, characterized in that each flow management process (28-31; PGF1-PGF5) is adapted to process the data at each moment with a single synchronized buffer of a memory line, then to release this synchronized buffer at the end of processing, the use of different synchronized buffers of a memory line by each flow management process is performed successively, one after the other, so that several processes of Flow management can be active simultaneously on different synchronized buffers. 5 / - Device according to one of claims 1 to 4, characterized in that the administration module (32) is a library of functions which comprises the following functions: - creation of the administration zone (4) and the useful area (5) of the self-administered memory (3), - initialization of a memory line with a maximum filling rate of the useful area (5) for this memory line, - creation of a synchronized buffer in a memory line, - release of a synchronized buffer, - access to a buffer synchronized by an active process, - determination of the subsequent active process on the sequence of use of a synchronized buffer of a memory line after release of the latter by the previous active process. 6 / - Device according to one of claims 1 to 5, characterized in that the switcher process (27) is adapted to define, for each track of each multitrack stream to be processed, at least one memory line dedicated to the processing of this track . 7 / - Device according to claim 6, characterized in that the switcher process (27) is adapted to define, for each track of each multitrack stream to be processed and for each flow management process processing data of this track, at least a source memory line providing data to be processed by the flow management process and / or at least one destination memory line receiving data processed by the flow management process. 8 / - Device according to one of claims 1 to 7, characterized in that the switcher process (27) is adapted to define a single sequence of use for all synchronized buffers of the same memory line.  9 / - Device according to one of claims 1 to 8, characterized in that the switcher process (27) is adapted to transmit the sequence of use of each memory line to the first flow management process to be active on a buffer synchronized with this memory line, this flow management process being the creator of this synchronized buffer and defining and recording in the administration zone (4) data identifying this synchronized buffer and associating it with the memory line, and with the sequence use. 10 / - Device according to one of claims 1 to 9, characterized in that the switcher process (27) is adapted to calculate, depending on the nature of each multitrack stream to be processed, a maximum size of the useful area (5). ) of the self-administered memory (3) that can be given to each memory line. 11 / - Device according to one of claims 1 to 10, characterized in that the flow management processes (28-31; PGF1-PGF5) are distinct, each of them performing at least one task of its own. 12 / - Device according to one of claims 1 to 11, characterized in that it comprises at least one application program, said launcher module, adapted to load in the RAM the various processes and modules for the configuration and operation of the self-administered memory of which: - the switcher process (27), each stream management process that can be used for processing multitrack streams, the administration module (32), a module (26) for dynamic windowing on a display screen of the device, adapted to form a human / machine interface allowing a user to define each multitrack stream to be processed from source data of various origins. 13 / - Device according to one of claims 1 to 12, characterized in that it comprises: at least one flow management process, referred to as the loading process, capable of writing data in the useful zone (5) of the self-administered memory, - At least one flow management process, said unloading process, able to read data from the useful area (5) of the self-administered memory. 14 / - Device according to one of claims 1 to 13, characterized in that the flow management processes are adapted to be loaded into a RAM area separate from the self-administered memory (3). 15 / - Device according to one of claims 1 to 14, characterized in that the switcher process (27) is adapted to be loaded into a RAM area separate from the self-administered memory (3). 16 / - Device according to one of claims 1 to 15, characterized in that the switching process (27) is suitable for: in a first analysis step, analyzing the characteristics of each multitrack stream to be processed and the processing constraints of each multitrack stream, so as to define the data representing the memory lines, and data representing each sequence of use of the buffers synchronized each memory line for processing this multitrack stream to be processed, - Then in a second subsequent processing step, start the processing of the multitrack stream according to said data previously defined during the analysis step. 17 / - Device according to one of claims 1 to 16, characterized in that the size of the self-administered memory (3) is defined by the configuration means to a predetermined fixed value. 18 / - Device according to claim 17, characterized in that the size of the self-administered memory (3) is between 20% and 80% of that of the virtual memory. 19 / - Device according to one of claims 1 to 18, characterized in that the size of the administration zone (4) is defined by the configuration means to a predetermined fixed value. 20 / - Device according to one of claims 1 to 19, characterized in that the self-administered memory (3) is defined by the switcher process (27) during its loading in RAM. 21 / - Device according to one of claims 1 to 20, characterized in that the configuration means are adapted to allow the processing of multitrack streams that are audiovisual streams. 22 / - Device according to one of claims 1 to 21, characterized in that the configuration means are adapted to allow the processing of multitrack streams having tracks whose format is selected from: - HDTV formats (HDTV) ) - standard definition television formats (TVSD), - digital cinema formats, - compressed video formats (MPEG2, MPEG4, DV ...), - uncompressed audio formats, - compressed audio formats, - multitrack encapsulation formats, - image formats, - raw audiovisual data formats.