JP3325807B2 - How to control virtual files - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a virtual file used in a video reproducing apparatus which receives and decodes compression-encoded video information transmitted via a communication network, and particularly relates to a method for controlling a virtual file. The present invention relates to a virtual file control method capable of shortening a response time of a change in a reproduction mode requiring continuous video information.

[0002]

2. Description of the Related Art FIG. 1 is a diagram showing a configuration example of a video reproducing apparatus, wherein 1 is a video reproducing apparatus, 2 is an apparatus control section, 3 is a communication section, 4 is a virtual file section, 5 is a reproduction control section, 6 is a decoder and 7 is a video server. Video playback device 1
Is a device in which a device control unit 2, a communication unit 3, a virtual file unit 4, a reproduction control unit 5, and a decoder 6 are built in a basic personal computer.

The device control unit 2 is configured as a control program on a personal computer. The device control unit 2 has an interface with a user, an interface with a communication unit 3, an interface with a virtual file unit 4, and an interface with a reproduction control unit 5. Have.

[0006] The communication section 3 is composed of communication interface hardware and a control program on a personal computer, and has an interface with the apparatus control section 2 and an interface with the video server 7.

The virtual file section 4 is composed of two buffer areas secured on the memory of the personal computer and a control program on the personal computer, and has an interface with the apparatus control section 2 and an interface with the reproduction control section 5. Having.

The reproduction control unit 5 is configured as a control program on a personal computer, and has an interface with the device control unit 2, an interface with the virtual file unit 4, and an interface with the decoder 6. The decoder 6 is constituted by a decoding board, and has an interface with the reproduction control unit 5, a video terminal connected to a display device (television monitor), and an audio terminal connected to a speaker. The video server 7 is connected to communication interface hardware of the communication unit 3 via a communication network.

The arrows in FIG. 1 indicate the direction of transmission of video information. The user instructs the device control unit 2 on the title of the video information to be viewed and its reproduction. The device control unit 2 requests the specified video information from the video server 7 via the communication unit 3. When the video information requested by the video server 7 starts to be sent to the video playback device 1, the device control unit 2 receives the video information via the communication unit 3 and writes the video information into the virtual file unit 4. Device control unit 2
In parallel with the start of writing of the video information to the virtual file unit 4, MCI (Multitime) of the standard interface
The playback control unit 5 is controlled in accordance with a procedure according to “dia Control Interface”. In accordance with this, the reproduction control unit 5 reads the video information from the virtual file unit 4 and transfers it to the decoder 6. The decoder 6 outputs a video signal to a video terminal and an audio signal to an audio terminal while expanding and decoding the received video information.

In the virtual file section 4, the control program executes a read / write process of video information using two buffer areas (referred to as buffer 0 and buffer 1 respectively). Video information is read almost serially by its nature, but the header part may be read at random. Accordingly, the release of the buffer storing the video information is executed when the reading of the other buffer storing the subsequent video information starts. In consideration of this random access, the size of the buffer is set to an appropriate data capacity C (for example, 160 k
B) is set in advance. From the beginning, video information divided for each data capacity C is called a segment.
The data amount W to be written to the buffer in one request is set in advance to 1 / N of the segment (1 / N, for example, 16 kB). The buffer divided into W units is called a section. To one buffer,
Up to N = C / W write operations are performed. If the user instructs to change the playback mode (such as a jump) that requires discontinuous video information in content, to reduce the response time, it is possible to change the segment before the playback mode change. Are discarded. Excluding this discarded segment, the video information is shifted to the front, which is the substance of the virtual file.

FIG. 6 is a diagram showing a processing flow of a conventional virtual file control method. Before starting reproduction of the video information of the new title, the buffer number i, the number n of times of writing to the buffer being used for writing (to be referred to as the current writing buffer), and the virtual file (byte) of the first byte of the current writing buffer Byte position p on 0)
And the full information s (i) of the buffer i are initialized to 0, respectively.

In response to a request from the higher-level device control unit 2 or the reproduction control unit 5, a process of reading and writing to the virtual file unit 4 is started via the operating system (OS) (10). Next, it is determined whether it is a write request (11),
In the case of a write request, the process proceeds to step 12, and in the case of a read request, the process proceeds to step 22.

If it is a write request, it is first determined in step 12 whether s (0) s (1) = 1, that is, whether both buffers are full. If so, a higher-level OS is requested to start again after a predetermined time (1
3) After that, the process ends (21). On the other hand, if no, the process proceeds to step 14 where section n of buffer i
The data passed from the device control unit 2 is written into the buffer (writing immediately after the reproduction instruction from the user starts from section 0 of the buffer 0). Next, 1 is added to n (15),
It is determined whether n = N, that is, whether or not the current write buffer i has reached a full state (16). In the case of No, the completion of the current write processing is reported to the upper OS (2
0), and the process ends (21). On the other hand, when the write buffer reaches the full state, the full state s (i) of the buffer i is set to 1, that is, the full state (17), and s (0).
It is determined whether s (1) = 1, that is, whether both buffers are full (18). If so, the process proceeds to step 20. On the other hand, in the case of no, it means that the other buffer is free, so that the remainder of the modulo 2 (mod2) of i and 1 is i, and
C is added to p (19). That is, the other buffer is used as the current write buffer, the number of writes n is initialized, and the byte position of the first byte on the virtual file is calculated and held. Next, in step 20, the completion of the current writing process is reported to the upper OS, and
In step 21, the process ends.

If it is a read request, first, at step 22, the full information of the buffer which is not the current write buffer is set to x, and then at step 23, the position of the read data is changed from the buffer p-xC on the virtual file to the byte. p + nW
It is determined whether it is within the range of -1. If not,
Assuming that the data writing process is not in time (underflow), requesting a higher-level OS to start again after a predetermined time (or reporting the occurrence of a failure) (24), and then processing Is ended (31). on the other hand,
If it is within the range, the requested data reading process is executed (25), and it is determined whether or not the data whose byte position on the virtual file is equal to or greater than byte p is read for the first time (26). If not, the process proceeds to Step 30. On the other hand, if it is equal to or greater than byte p, step 2
In step 7, it is determined whether s (0) s (1) = 1, that is, whether both buffers are full, and if not, the process proceeds to step 29. On the other hand, when the state is full, the remainder of the modulus 2 (mod2) of the sum of i and 1 is defined as i, and
n is set to 0, and C is added to p (28). That is, the current write buffer, which has been held in a full state, is switched to the other buffer, the number of writes n is initialized, and the byte position of the first byte on the virtual file is calculated and held. In step 29, the full information of the other buffer other than the current write buffer is set to 0 and released. Further, in step 30, the completion of the current reading process is reported to the upper OS, and the process is terminated in step 31.

FIG. 7 is a diagram schematically showing a virtual file constructed by the above-mentioned conventional control method. A column of squares represents a virtual file, and one square represents one segment. The segments are written alternately with buffer 0 and buffer 1 sequentially from the head A of the virtual file. The number in the rectangle indicates the buffer number where the segment is written. When the reading of the trailing segment on the two buffers begins, the buffer in which the leading segment is being written is freed and used to write further trailing segments. A bold square indicates the segment currently located on the buffer.

Now, it is assumed that a request to change the reproduction mode requiring discontinuous video information, such as a jump, occurs while reading and reproducing the point B of the preceding segment on the buffer 1. At this time, the old segment before the playback mode change temporarily stored in the video server 7, the communication unit 3, and the device control unit 2 is discarded, and the new segment (shaded rectangle) after the playback mode change is discarded. Left justified on the virtual file. However, the following processing must be performed before the reproduction control unit 5 reads this new segment from the virtual file unit 4. First, after reading all the remaining data in the buffer 1 that was being read when the reproduction mode was changed, the data in the other buffer 0 is started to be read.
At this point, since buffer 1 is released, writing of a new segment into buffer 1 is started. When the new segment is written to a certain amount, the reproduction control unit 5 starts reading the new segment in accordance with an instruction from the device control unit 2.

[0015]

As described above, in the conventional virtual file control method, there is no means for detecting that the video information to be written is new video information after the change of the reproduction mode. There is a problem that the old video information already written thereon cannot be discarded. That is, it is necessary to read the old video information already written on the buffer before the reading / reproduction of the new video information is started, so that there is a problem that the response time of the reproduction mode change becomes long.

An object of the present invention is to provide a method of controlling a virtual file in a video playback apparatus, which can shorten the response time of a change in a playback mode that requires discontinuous video information.

[0017]

In order to solve the above-mentioned problems, a virtual file control method according to the present invention receives compression-encoded video information, writes the video information in a virtual file part, and reads the video information from the virtual file part. In a video playback device that reads and decodes video information, even when a write request to a given file different from the virtual file is made, even if the previous video information remains in the virtual file part, Writing of new video information to the virtual file portion, that is, a virtual file that starts overwriting
Control method, usually the received video information
Alternately write to two buffers in the virtual file part,
When a write request to a given file is made,
Buffer not the buffer used for reading at the time
To start writing the new video information from
It was done.

[0018]

Alternatively, the compressed and encoded video information is
Receives and writes to the virtual file part.
To the video playback device that reads and decodes the video information
Write to a given file separate from the virtual file
Earlier video, triggered by the request
Even if information remains in the virtual file section, the virtual file
Writing new video information to the unit, that is, starting overwriting
A control method of a virtual file which is adapted to, when the writing is normally alternately video information thus received to the two buffers of the virtual file unit, a write request to the given file is made, the The writing of the new video information is started from the buffer used for reading at the time.

According to the present invention, even when old video information remains in the buffer of the virtual file section, new video information is written to the buffer of the virtual file section without waiting for reading and releasing the buffer. By doing so, the response time of a playback mode change that requires discontinuous video information in content is reduced.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 shows a video reproducing apparatus to which the present invention is applied, which is the same as that described in the conventional example. That is, the video reproducing apparatus 1 to which the present invention is applied includes a device control unit 2, a communication unit 3, a virtual file unit 4, a reproduction control unit 5, and a decoder 6 in a basic personal computer.
, And as described above, the description is omitted. The following is also the same as the conventional example.

In the virtual file section 4, the control program executes a read / write process of video information using two buffer areas (referred to as buffer 0 and buffer 1 respectively). The release of the buffer storing the data is executed when the reading of the other buffer storing the subsequent data starts. The size of the buffer is set in advance to an appropriate data capacity C (for example, 160 kB). From the beginning, video information divided for each data capacity C is called a segment. The data amount W to be written to the buffer in one request is set in advance to 1 / N of the segment (1 / N, for example, 16 kB). The buffer divided into W units is called a section. Up to N = C /
W writes are performed.

FIGS. 2 and 3 are diagrams showing the processing flow of the first embodiment of the present invention. The * mark in FIG. 2 indicates that the processing flow continues to the * mark in FIG. ing. In the present embodiment, steps 10 to 31 are the same as the conventional example, and steps 40 to 43 are newly added.

First, before the reproduction of the video information of the new title is started, the buffer number i, the number n of times of writing to the buffer being used for writing (referred to as the current writing buffer), and the beginning of the current writing buffer The byte position p on the virtual file of bytes (starting at byte 0) and the full information s (i) of the buffer i are each initialized to zero.

First, in response to a request from the host device control unit 2 or the reproduction control unit 5, the operating system (O
Through S), the read / write processing for the virtual file unit 4 is started (10). Next, it is determined whether or not the request is a write request (11). If the request is a write request, the process proceeds to step 40. If the request is a read request, the process proceeds to the mark * in FIG.

If it is a write request, it is first determined in step 40 whether or not the request is for a given file. If so, the process proceeds to step 41, and if not, the process proceeds to step 12. In step 41, it is determined whether or not the data position of the latest read processing has reached byte p or more, that is, whether or not the data has entered the current write buffer. If so, the process proceeds to step 42; Proceed. Step 42 is a process in the case where the current write buffer and the buffer being used for reading (referred to as a current read buffer) are the same, and the sum of i and 1 modulo 2 (m
The remainder of od2) is set to i, C is added to p, and n is set to 0, and the process proceeds to step 14. That is, the write buffer is switched to the other buffer, and writing of a new segment is started from the beginning of the buffer as a segment following the segment on the current read buffer.
Step 43 is a case where the current write buffer and the current read buffer are different.
Proceed to 4. That is, assuming that there is no old segment in the current write buffer, writing of a new segment is started from the head of the buffer. Hereinafter, step 12
Since the writing process in steps S21 to S21 and the reading process in steps S22 to S31 are the same as those in the conventional example, description thereof will be omitted.

Table 1 summarizes the processing performed when a write request to a given file described above is made.

[0029]

[Table 1]

FIG. 4 is a diagram schematically showing a virtual file formed by the control method according to the first embodiment of the present invention. A column of squares represents a virtual file, and one square represents one segment. The segments are written alternately with buffer 0 and buffer 1 sequentially from the head A of the virtual file. The number in the rectangle indicates the buffer number where the segment is written. 2
When reading of a subsequent segment on one buffer begins, the buffer in which the preceding segment is being written is freed and used to write additional subsequent segments. A bold square indicates the segment currently located on the buffer.

Now, it is assumed that a request for changing the reproduction mode requiring discontinuous video information such as a jump occurs while reading and reproducing the point B of the preceding segment on the buffer 1. At this time, the old segment before the change of the reproduction mode temporarily stored in the video server 7, the communication unit 3, and the device control unit 2 is discarded as in the conventional example. According to the present invention, even when the old segment has already been written to the buffer 0, the new segment (shaded rectangle) after the change of the reproduction mode is left-justified on the virtual file, assuming that this has not occurred. That is, when the device control unit 2 requests the writing of the first new segment for a given file, the first new segment is written to the buffer 0 as a succeeding segment of the current read buffer 1. When the new segment is written to a certain amount, the reproduction control unit 5 starts reading the new segment in accordance with an instruction from the device control unit 2.

FIG. 5 is a diagram showing a processing flow of the second embodiment of the present invention. The mark * in FIG. 5 indicates that the processing flow continues to the mark * in FIG. As in the first embodiment, steps 10 to 31 are the same as the conventional example, and steps 40, 41, 5
2. Step 53 is newly added. Hereinafter, the operation of this additional step will be described.

If it is a write request, it is first determined in step 40 whether or not the request is for a given file.
If so, go to step 41; if no, go to step 12
Processing proceeds to In step 41, it is determined whether or not the data position of the latest read processing has reached the byte p or more, that is, whether or not the data has entered the current write buffer. If so, the processing proceeds to step 52; Proceed. Step 52 is a case where the current write buffer and the read buffer are the same, and adds C to p, sets n to 0, and advances the processing to step 14. That is, the writing of a new segment is started from the beginning of the current read (and write) buffer as the segment following the segment on the buffer. Step 53 is a case where the current write buffer and the current read buffer are different. The remainder of the modulo 2 (mod2) of i and 1 is set to i, n is set to 0, and the process proceeds to step 14. That is, the write buffer is switched to the other buffer (current read buffer),
Begin writing a new segment from the beginning of the buffer as the next segment after the segment on the current read buffer.

Table 2 summarizes the processing performed when a write request to a given file described above is made.

[0035]

[Table 2]

In the case of the second embodiment, the new segment shown in FIG. 4 is written into the buffer 1 used for reading at the point B when the request for changing the reproduction mode occurs. . Thereafter, the new segment is written to buffer 0 and buffer 1 alternately.

[0037]

As described above, according to the present invention,
Even if old video information remains in the buffer of the virtual file section, the new video information can be written to the buffer of the virtual file section without waiting for it to be read and the buffer to be released. There is an advantage that the response time of a reproduction mode change that requires discontinuous video information can be shortened.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a configuration example of a video playback device to which the present invention is applied.

FIG. 2 is a diagram showing a processing flow of the first embodiment of the present invention.

FIG. 3 is a diagram showing a continuation of the processing flow of the first and second embodiments of the present invention.

FIG. 4 is a diagram schematically showing a virtual file configured by the control method according to the first embodiment.

FIG. 5 is a diagram showing a processing flow according to a second embodiment of the present invention.

FIG. 6 is a diagram showing a processing flow of a conventional virtual file control method.

FIG. 7 is a diagram schematically illustrating a virtual file configured by a conventional control method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Video reproduction apparatus 2 ... Device control part 3 ... Communication part 4 ... Virtual file part 5 ... Reproduction control part 6 ... Decoder 7 ... Video server 10-31 ... Processing steps of the conventional virtual file control method 40-43 ... Processing steps newly added in the first embodiment of the present invention 52, 53 ... Processing steps changed in the second embodiment of the present invention A: Head of virtual file B ... Discontinuous in content Example of when a request for changing the playback mode that requires special video information occurs

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Satoshi Matsuda 3-19-2 Nishi-Shinjuku, Shinjuku-ku, Tokyo Nippon Telegraph and Telephone Corporation (56) References JP-A-9-154123 (JP, A) JP-A-8-79685 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H04N 5/91-5/956 H04N ^7/ 24-7/68

Claims (2)

(57) [Claims] 1. Receiving compression-encoded video information
Write to the virtual file part, and
In a video playback device that reads and decodes video information , a write request to a given file different from a virtual file
As a result, the previous video information is temporarily
Even if it remains in the virtual file section, new
To start writing over the video information
A method of controlling a virtual file according to claim 1 , wherein the received video information is normally written alternately in two buffers of a virtual file part, and when a write request to the given file is made, A method for controlling a virtual file, wherein writing of the new video information is started from a buffer other than the buffer used for reading. 2. Receiving compression-encoded video information
Write to the virtual file part, and
In a video playback device that reads and decodes video information , a write request to a given file different from a virtual file
As a result, the previous video information is temporarily
Even if it remains in the virtual file section, new
To start writing over the video information
A method of controlling a virtual file according to claim 1 , wherein the received video information is normally written alternately in two buffers of a virtual file part, and when a write request to the given file is made, A method for controlling a virtual file, wherein writing of the new video information is started from a buffer used for reading.