FR2996398A1 - Method for obtaining recorded multimedia content from e.g. audio flow captured by camera, involves triggering restitution of multi-media content and recording of data representative of portion of flow during its reception at instant - Google Patents

Abstract

The method involves detecting reception of a flow through one of transmission channels (L1, L2), and controlling the reception of multi-media content (C1) through third transmission channel (LC) following the detection. Reception of beginning of the multimedia content is detected by the third channel. Restitution of the multi-media content and the recording of data representative of a portion of the flow during its reception through the first channel are triggered at instant, where the data constitutes second multi-media content. Independent claims are also included for the following: (1) a device for obtaining recorded multimedia contents from a received flow (2) a system comprising a flow capture device.

Description

The invention relates to the field of the recording of audiovisual streams. Known systems make it possible to obtain multimedia content by recording one or more audio and / or video streams. For example, it is known to obtain multimedia content by simultaneously recording a video signal obtained by a camera and an audio signal obtained by a microphone. The content obtained can then be stored and then restored by a rendering system comprising for example a screen and speakers. It is thus possible to obtain multimedia content such as, for example, musical content containing several voices and / or several instruments. For practical reasons, but also for sound quality, the recording of such content is often done by separate recording of the different voices and / or instruments. The different recordings obtained must then be synchronized before being mixed in order to obtain audible content when rendering and whose images are synchronized with the sound. Such synchronization requires the use of heavy, dedicated software that requires advanced technical knowledge from the user. In addition, it requires manual calibration by viewing flows to be synchronized on a screen. There is therefore a need for a simple solution for recording one or more audio and / or video streams synchronized with predetermined pre-recorded multimedia content. The invention improves the situation. To this end, the invention relates to a method for obtaining a multimedia content recorded from at least one received stream, comprising the following steps: - detection of the reception of at least one stream, via the minus a first transmission channel; control, following said detection, of the reception of a first multimedia content via a second transmission channel; detecting, at a first instant, reception of the beginning of the first multimedia content via said second channel; Triggering, at a second instant following said first instant, the restitution of the first multimedia content and the recording of data representative of at least a portion of at least one stream being received via a said at least one first channel, said data constituting a second multimedia content. The step of detecting the reception of at least one stream makes it possible to ensure the operation of the one or more capture devices enabling acquisition of the said at least one stream. The command sent to receive a first multimedia content after this detection step makes it possible to start receiving the requested content as soon as the said at least one stream is in the process of being received. As soon as the reception of the ordered content is detected, it is then possible to order the recording of at least a portion of at least one of the streams being received simultaneously with the return of the first content. The recorded data constitutes a second multimedia content.

Thus, the beginning of the second multimedia content is synchronized with the beginning of the first multimedia content. By synchronization, it is understood that the reproduction of the first content and the recording of the second multimedia content begin at the same time, or with a predetermined offset. According to a particular embodiment, the method of obtaining also comprises the following steps: detection at a third moment of the end of reception of the first multimedia content; triggering the stopping of the recording at a fourth instant, the interval of time separating the fourth instant and the third instant being equal to the time interval separating the second instant and the first instant. The method thus makes it possible to obtain a second multimedia whose beginning is synchronized with the beginning of the first multimedia content and whose duration is identical to that of the first multimedia content. It is thus possible to render a second content obtained simultaneously to the first content and / or to another second multimedia content obtained by the method obtained from the same multimedia content without the need for processing the second content. According to a particular embodiment of the method of obtaining, used alone or in combination with the preceding embodiment, the data representative of a portion of a stream comprise data representative of a portion of said stream received from a reception instant, the time interval separating said reception instant and the second instant being less than a predefined difference value. The time interval separating the instant of reception and the second instant allows a time shift between the recorded portion of the stream and the first rendered content. This offset makes it possible to take into account data transmission delay differences between the different pieces of equipment, in particular between a database hosting the first content and the processing device and between a device for capturing a stream and the processing device. . According to one embodiment of the obtaining method, the step of detecting at least one stream comprises the detection of a video stream and an audio stream the second multimedia content contains an audiovisual stream comprising a portion of the video stream detected and a portion of the detected audio stream.

Simultaneous recording of an audio component and a video component received from two capture devices, for example a microphone and a camera makes it possible to obtain multimedia content. According to a particular characteristic, said portion of the stream audio is received from a first predetermined reception instant and said portion of the video stream is received from a second predetermined reception time The time offset between the first reception time and the second reception time allows to take account different transmission delays between the capture device and the device implementing the invention. According to a particular embodiment of the obtaining method, the first multimedia content comprises a video component and an audio component and the first moment is the moment of reception of a beginning of a signal representative of the audio component.

Synchronization from the reception of the audio component is simple to implement. According to a particular embodiment of the obtaining method, the first multimedia content is received in the form of N video signal samples and N audio signal samples of predetermined duration and the first moment is the reception time of the beginning of the first received audio sample and said data representative of a portion of a stream comprise N successive samples of said stream. In this embodiment, a recorded stream portion has the same number of signal samples as a component of the first C content. It has the same duration as the C content.

The invention also relates to a multimedia content comprising data representative of at least a portion of at least one stream characterized in that it is obtained by a method of obtaining as described above. The invention also relates to a device for obtaining a multimedia content recorded from at least one received stream, characterized in that it comprises: a module for detecting the reception of at least one stream via at least one first transmission channel; a control module, following said detection, of the reception of a first multimedia content via a second transmission channel; a detection module, at a first instant, receiving the beginning of the first multimedia content via the second channel; a triggering module, at a second instant following the first instant, of the restitution of the first multimedia content and the recording of data representative of at least a portion of at least one stream being received via a said least one first channel, said data constituting a second multimedia content.

The invention also relates to a system comprising at least one flux capture device and a device for obtaining such as described above. The invention finally relates to a computer program product comprising instructions for implementing implement the steps of a method of obtaining a multimedia content recorded from at least one received stream, as described above, when it is loaded and executed by a processor.

Other features and advantages of the present invention will appear in the following description of embodiments given as non-limiting examples, with reference to the accompanying drawings, in which: - Figure 1 is a block diagram illustrating a system according to a Embodiment of the Invention, FIG. 2 is a flowchart illustrating the various steps of a method for obtaining multimedia content, according to a first embodiment, FIG. 3 is a timing diagram illustrating data. representative of a content obtained, according to the first embodiment, - Figure 4 is a flowchart illustrating the different steps of a method of obtaining a multimedia content, according to a second embodiment, - Figure 5 is a timing diagram illustrating data representative of a content obtained, according to the second embodiment.

The invention is implemented by means of software and / or hardware components. In this context, the term "module" may correspond in this document to a software component, to a hardware component or to a set of hardware and / or software components, capable of implementing a function or set of functions, as described below for the module concerned.

A software component corresponds to one or more computer programs, one or more subroutines of a program, or more generally to any element of a program or software. Such software component is stored in memory then loaded and executed by a data processor of a physical entity (terminal, server, gateway, set-topbox, router, etc.) and is able to access the hardware resources of this physical entity (memories, recording media, communication bus, input / output electronic boards, user interfaces, etc.). In the same way, a material component corresponds to any element of a material set (or hardware). It may be a programmable hardware component or with an integrated processor for running software, for example an integrated circuit, a smart card, an electronic card for executing a firmware, etc. A first embodiment of a method for obtaining multimedia content will now be described with reference to FIGS. 1 to 3. With reference to FIG. 1, a SYS system comprises a PC processing device, a first PCM capture device, a second CAM stream capture device, an ECR display screen, an HP sound reproduction device and a DC database. The processing device PC is able to control the first and the second capture device. The first PCM flux capture device is for example a microphone connected to the PC processing device. The first PCM capture device is adapted to be controlled by the PC processing device for capturing and transmitting to the processing device PC, via a transmission channel Li, an audio stream FA1. The second CAM flow capture device is for example a camera, for example of the Webcam type (registered trademark), connected to the processing device PC. The second CAM flow capture device is adapted to be controlled by the processing device PC to capture and transmit to the processing device PC, via a transmission channel L2, a video stream FV1. The transmission channel Li and the transmission channel L2 represent first transmission channels. The sound reproduction device HP is for example a headphone connected to the PC processing device.

As an alternative, the sound reproduction device HP consists of one or more speakers accessible by the PC processing device. The DC database contains one or more multimedia contents. The processing device PC is for example a computer type PC (for "Personal Computer").

The processing device PC comprises a processing unit UT provided with a microprocessor, connected to one or more RAM memories MV and to one or more ROM memories MM. The processing unit UT is driven by a computer program PG. The computer program PG includes program instructions adapted to implement in particular a method of obtaining a multimedia content according to an embodiment of the invention described later. The processing device PC is able to control the first and the second capture device. The processing device PC also comprises a first reception module RF1, a second reception module RF2, an access module LEC, a recording module ENR, a reproduction module RST and a synchronization module SYN. More generally, the SYS system comprises one or more capture devices and the PC processing device comprises one or more reception modules. A reception module is able to receive an audiovisual stream coming from a capture device. In the embodiment described, the reception, access, reproduction, recording and synchronization modules are integrated in a single device, the processing device PC. As an alternative, these modules are integrated in several devices connected to the processing device PC, for example via a wired link. The ECR screen and the HP sound reproduction device are connected to the PC processing device. As an alternative, they are integrated in the PC processing device. Also, as an alternative, one or more links between the devices are wireless links. The reception module RF1 is able to receive the audio stream FA1 The reception module RF2 is able to receive the video stream FV1 The access module LEC is able to access the database DC and to obtain a multimedia content C1 previously stored in the database DC, via a second channel of transmission LC. The content C1 represents a first multimedia content.

As an alternative, the multimedia content C1 is previously stored in a memory of the processing device PC. The multimedia content C1 comprises a video component and an audio component. As an alternative, the content C1 contains a video component and / or at least one audio component.

The rendering module RST is capable of rendering a multimedia content, for example the content C1. The rendering module RST is in particular able to render the video component of the content C1 on the screen ECR and simultaneously the audio component of the content C1 on the screen. HP rendering device. The recording module ENR is able to obtain multimedia content by recording one or more streams received by the processing device PC. The recording module ENR is capable of obtaining multimedia content C2 by recording at least one video component of at least one stream and / or at least one audio component of at least one stream. The SYN synchronization module comprises a DTF flow detection module, a CMD control module, a DTC content detection module and a DCL trigger module. A first embodiment of a method for obtaining a multimedia content implemented in the SYS system will now be described with reference to FIG. 2. During a prior EO step, a user chooses a multimedia content C1 among a set of multimedia contents contained in the database DC. The content Cl is for example chosen by the user by means of a graphical interface displayed on the ECR screen and on which is displayed a list of contents accessible by the user. During a step E2, the processing device PC detects a recording command CME. The registration command CME is for example formulated by the user. The recording command is for example performed by the user by means of, for example, a command button displayed on the screen ECR and selected by the user, for example by means of a computer mouse. During a step E4, the flow detection module DTF tests each first transmission channel connected to a capture device. The flow detection module DTF tests the transmission channel Li and the transmission channel L2. The flow detection module DTF thus determines whether or not each capture device transmits a stream. More specifically, it determines whether a signal representative of a stream is received or not from each capture device. In the case where a capture device transmits a signal, step E4 is repeated. If no signal is received after a predetermined period of time, the process stops. In this case, the user is for example notified by displaying on the ECR screen a message indicating the absence of a signal. During a step E6, following step E4, the flow detection module DTF detects the reception of a stream coming from each flow capture device. The flow detection module DTF detects, on the one hand, the reception on the transmission channel Li, of the video stream FV1 coming from the CAM camera and, on the other hand, the reception on the transmission channel L2 of the audio stream FA1. from the MIC microphone. Step E6 is followed by a step E8 during which the CMD control module sends a read command to the access module. On receipt of the read command, the access module LEC sends to the database DC, a CMA access command to the first multimedia content Cl. The sending of the access control CMA causes the transmission of the first content C1 from the database DC to the access module LEC, via the second channel of transmission LC. And, during a step E10, following step E8, the content detection module DTC detects, at a time Ti, the beginning of reception of the first multimedia content C1, via the second transmission channel LC. The moment Ti represents a first moment. The first content C1 is received in the form of a signal SG1. The beginning of reception of the first content C1 corresponds to the beginning of reception of a signal on the second transmission link, here the signal SG1. During a step E12, carried out at a second instant T2, consecutive to the first instant Ti, the triggering module DCL controls on the one hand the restitution of the first multimedia content -8-C1 by the rendering module RST and on the other hand the recording by the recording module ENR DF data representative of at least a portion of at least one stream being received on a first transmission channel. The DF data constitutes a second multimedia content C2.

In the embodiment described, the data DF are data representative of a portion of the video stream FV1 and data representative of a portion of the audio stream FAL. As an alternative, the data DF are data representative of a portion of the audio stream FAl. The first content C1 is rendered in the form of a signal SG2, identical to the signal SG1.

During a step E14, performed subsequently, the content detection module DTC detects, at a third time T3, the end of reception of the first multimedia content C1. The end of reception corresponds for example to a representative signal reception end content C1 on the second channel of transmission LC. The step E14 is followed by a step E16 during which the triggering module DCL commands, at a fourth instant T4, the stopping of the recording by the recording module ENR. The fourth time T4 is determined so that the time interval separating the fourth instant T4 and the third instant T3 is equal to the time interval separating the second instant T2 and the first instant T1.

In the embodiment described, the stopping of the recording is caused by the detection of the end of reception of the first multimedia content C1. The duration of each recorded portion is equal to the playback time of the first multimedia content. Alternatively, the DCL trigger module causes the recording module ENR to stop recording after a predetermined period of time. The duration of each recorded portion is in this case of a predefined value. FIG. 3 is a diagram illustrating DF data representative of a second content C2 obtained during the restitution of the first content C1. The first content C1 is received and detected during a time interval between the first instant Ti and the third instant T3. .

At the second instant T2, the processing device PC controls the restitution of the first content C1. The first content C1 is restored during a time interval between the second instant T2 and the fourth instant T4. A time interval H separates the second instant T2 and the first instant T1. The interval H is, for example, a few milliseconds. A time interval 12 separates the fourth instant T4 and the third instant T3. The time interval 12 is equal to the time interval II. As an alternative, the first content C1 is restored with a time offset Dr with respect to the second time T2. The time offset Dr is, for example, a few milliseconds and allows a running time to be taken into account between the sending by the DCL trigger module of a recording command to the recording module ENR and the execution of this command by the recording module ENR. In this case, the first content C1 is restored during a time interval between T2 + Dr and T4 + Dr. Also, at the second instant T2, the processing device PC controls the recording of a portion PA1 of the audio stream FA1 and a portion PV 1 of the video stream. The portion PA1 of the stream FA1 is for example the portion of the stream FA1 received between the instants TA1 and TA2. The instant TA1 represents a first reception instant. A time interval 13 separates the first reception instant TA1 and the second instant T2. The time interval 13 is less than a predefined deviation value D. The time interval 13 is for example a few milliseconds. The difference value D is for example 10 milliseconds.

The portion PV1 of the stream FV1 is for example the portion of the stream FV1 received between the times TV 1 and TV2. The moment TV 1 represents a second moment of reception. A time interval 14 separates the second reception instant TV1 and the second instant T2. The time interval 14 is less than the difference value D. The time interval 14 is, for example, a few milliseconds.

The time interval 13 is indifferently less than or greater than the time interval 14. The time intervals 13 and 14 make it possible to take into account a difference in transmission delays between on the one hand the processing device PC and on the other hand. on the other hand the first capture device, the second capture device and the DC database. A time interval 15 separates the instant TA2 and the fourth instant T4. The time interval 15 has the same duration as the time interval 13. A time interval 16 separates the instant TV2 and the fourth instant T4. The time interval 16 has the same duration as the time interval 14. As an alternative, the instants TA1 and TV 1 are identical. Also, as an alternative, the instant TA1 and / or the instant TV1 are respectively identical to the second instant T2. In a particular embodiment, the time interval H is zero and the second time T2 is the first time Ti. In the embodiment described, step E6 is a step of detecting the reception of a stream coming from each capture device.

Alternatively, step E6 is a step of detecting the reception of at least one stream from at least one capture device of the processing device via at least a first predetermined transmission channel and the step E4 is a step of testing the first predetermined transmission channel A second embodiment of a method for obtaining a multimedia content implemented in the SYS system will now be described with reference to FIGS. 4 and 5. this embodiment, the first content C1 is received in the form of signal samples. Specifically, the first content C1 comprising an audio component and a video component, the audio component is received in the form of consecutive audio signal samples, and the video component is received as consecutive video signal samples. The duration DE of each sample is a predefined value, for example 40 ms (for "milliseconds"). A sample is received in response to a sample request by the access module LEC. FIG. 4 is a flowchart illustrating the various steps of a method for obtaining a multimedia content.

During a prior step E20, a user chooses a multimedia content C1 from a set of multimedia contents contained in the database DC. The selected multimedia content C1 comprises, for example, an audio component relating to a song, for example a musical tune and sung words. The content Cl also includes a video component representing a choir director punctuating the song.

In a step E22, the processing device PC detects a registration request CME. During a step E24, the flow detection module DTF tests the transmission channel Li and the transmission channel L2. During a step E26, following step E24, the flow detection module DTF detects the reception of a stream coming from each CAM and PCM capture device. Steps E20, E22, E24 and E26 are similar respectively to steps E0, E2, E4 and E6 described in connection with the first embodiment. Step E26 is followed by a step E28 during which the control module CMD controls the reception by the access module LEC of the first content C1 and the access module LEC sends, to the database DC, a access control to the multimedia content C1 The command sent to the database DC is, in this embodiment, a DMA request of a first sample of audio signal for the content C1. The access module LEC also sends, to the database DC, a DMV request of a first video sample.

Step E28 is followed by a step E30 in which the access module LEC receives, via the second transmission channel, a first audio signal sample CA1. The access module LEC also receives a first video signal sample CV i. In step E32 following step E30, the content detection module DTC detects, at a first instant Ti, the reception start of the first multimedia content C1. The first instant T1 is the instant of receiving the beginning of the first sample EC1. Then, during a step E34, carried out at a second instant T2, consecutive to the first instant Ti, the triggering module DCL controls the reproduction by the rendering module RST of the first audio signal sample CA1 and the simultaneous reproduction of the first sample CV1 video signal. At the same time T2, the triggering module DCL also controls the recording, by the recording module ENR, of a sample EV1 of the video stream FV1 being received and a sample EA1 of the audio stream FA1 being played. reception.

Samples EV1 and EA1 respectively have the same duration DE as the received sample CA1. The sample EA1 corresponds for example to a portion of the stream FA1, received from a first reception instant TAI. The sample EV1 corresponds, for example, to a portion of the stream FV1 received from a second reception instant TV1.

In a step E36, the access module LEC sends a DMA request for a new audio signal sample and a DMV request for a new video signal sample. Step E36 is followed by a step E38 in which a new audio signal sample CA and a new video signal sample CV are received. The received sample CA and sample CV are transmitted to the rendering module RST during a step E40. In addition, also in step E40, an EV sample of the FV1 stream received following the previously recorded sample is recorded and an EA sample of the FA1 stream received following the previously recorded sample is recorded. Steps E36, E38 and E40 are repeated as long as a CA sample is received in response to a DMA sample request.

N consecutive samples CA1, CA2 ... CAn of the audio component of the first multimedia content C1 are thus received and returned by the HP rendering device. N consecutive samples CV1, CV2 ... CVn of the video component of the first multimedia content CI are thus received and restored on the screen ECR, simultaneously with the samples CA1, CA2 ... CAn.

N consecutive samples EV1, EV2 ... EVn of the video stream FV1 and N consecutive samples EA1, EA2 ... EAn of the audio stream FA1 are recorded. Figure 5 is a timing diagram illustrating the recorded samples as well as the samples of the first content C1 received and returned. The samples CA1, CA2 ... CAn received from the first instant Ti and restored from the second time T2. Samples CV1, CV2 ... CVn are restored from the second time T2. The samples EA1, EA2 ... EAn are recorded from the first reception instant TM. Samples EV1, EV2 ... EVn are recorded from the second reception time TV1. In a step E42, performed following a sample request step E36, the access module LEC does not receive a sample. The absence of a sample in response to a sample request is then significant from the end of the first multimedia content Cl. No new sample is received by the access module LEC, the reproduction of the first multimedia content Cl stops at the end of the return of the last sample CAn received and the recording of the stream portion FV1, respectively FA1, stops at the end of the recording of the sample EVn, respectively at the end of the sample EAn. The N samples EV1, EV2 ... EVn form a PV portion of the video stream FV1. The N samples EA1, EA2 ... EAn form a PA portion of the audio stream FAL Each portion of recorded stream contains as many samples as the first multimedia content C1. Each portion obtained is of the same duration as the first multimedia content C1. second multimedia content C2 contains the set of samples EA1, EA2 ... EAn and the set of samples EV1, EV2 ... EVn. As an alternative, the second content C2 is multimedia content obtained by assembling the video samples and audio samples.

Claims (10)

REVENDICATIONS1. Method for obtaining a multimedia content (C2) recorded from at least one received stream (FA1, FV1), characterized in that it comprises the following steps: - detection (E6, E26) of the reception of at least one stream (FA1, FV1) via at least one first transmission channel (L1, L2); control (E8, E28), following said detection, of the reception of a first multimedia content (C1) via a second transmission channel (LC); detecting (E10, E32), at a first instant (Ti), receiving the beginning of the first multimedia content via the second channel (LC); triggering (E12, E34), at a second instant (T2) consecutive to the first instant (Ti), the reproduction of the first multimedia content (C1) and the data recording (DF) representative of at least one portion (PA1, PV1) of at least one stream (FA1, FV1) being received via a said at least one first channel (L1, L2), said data constituting a second multimedia content (C2). 2. Method of obtaining according to claim 1 characterized in that it comprises the following steps: - detection (E14) at a third time (T3), the end of reception of the first multimedia content (C1); triggering (E16) the stopping of the recording at a fourth instant (T4), the interval of time separating the fourth instant (T4) and the third instant (T3) being equal to the time interval separating the second moment (T2) and the first moment (Ti). 3. Method of obtaining according to claim 1 wherein the data (DF) representative of a portion of a stream comprise data representative of a portion of said stream received from a reception instant (TA i, TV i), the time interval separating said reception instant (TA i, TV i) and the second instant (T2) being less than a predefined difference value (D). 4. Method of obtaining according to claim 1 wherein the step of detecting (E6, E26) at least one stream comprises the detection of a video stream and an audio stream and wherein the second multimedia content ( C2) contains an audiovisual stream comprising a portion (PV1) of the detected video stream and a portion (PA1) of a detected audio stream. 5. Production method according to claim 4 wherein said portion (PA1) of the audio stream is received from a first predetermined reception instant (TA1) and said portion (PV1) of the video stream is received from a second predetermined reception instant (TV1). 6. Production method according to claim 1, wherein the first multimedia content comprising a video component and an audio component, the first instant (Ti) is the instant of reception of a start of a signal representative of the audio component. . The method of obtaining according to claim 1 wherein the first multimedia content (C1) is received in the form of N video signal samples and N audio signal samples of predetermined duration and wherein the first time (Ti) is instant of reception of the beginning of the first received audio sample and said data representative of a portion of a stream comprise N successive samples of said stream. Multimedia content (C2) comprising data (DF) representative of at least a portion of at least one stream characterized in that it is obtained by a production method according to claim 1. 9. Device (PC) for obtaining a multimedia content recorded from at least one received stream, characterized in that it comprises: a detection module (DTF) for receiving at least one stream ( FA1, FV1) via at least one first transmission channel (L1, L2); a control module (CMD), following said detection, of the reception of a first multimedia content via a second transmission channel (LC); a detection module (DTC), at a first instant (Ti), of the reception of the beginning of the first multimedia content via the second channel (LC); a triggering module (DCL), at a second instant (T2) following the first instant (Ti), of the reproduction of the first multimedia content (C1) and the data recording (DF) representative of at least one portion (PA1, PV1) of at least one stream (FA1, FV1) being received via a said at least one first channel (L1, L2), said data constituting a second multimedia content (C2). 10. System comprising at least one flux capture device, characterized in that it comprises a production device according to claim 9.