JP2001086511A - Method and system for moving picture transmission - Google Patents

Method and system for moving picture transmission

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Publication number
JP2001086511A
JP2001086511A JP25678499A JP25678499A JP2001086511A JP 2001086511 A JP2001086511 A JP 2001086511A JP 25678499 A JP25678499 A JP 25678499A JP 25678499 A JP25678499 A JP 25678499A JP 2001086511 A JP2001086511 A JP 2001086511A
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JP
Japan
Prior art keywords
moving image
image data
frame
compression
unit
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
JP25678499A
Other languages
Japanese (ja)
Inventor
Yoshitaka Ota
Yoshiteru Shoji
Kazuaki Takamune
良▲たか▼ 太田
吉輝 庄司
和暁 高宗
Original Assignee
Matsushita Electric Ind Co Ltd
松下電器産業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Matsushita Electric Ind Co Ltd, 松下電器産業株式会社 filed Critical Matsushita Electric Ind Co Ltd
Priority to JP25678499A priority Critical patent/JP2001086511A/en
Publication of JP2001086511A publication Critical patent/JP2001086511A/en
Application status is Pending legal-status Critical

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Abstract

PROBLEM TO BE SOLVED: To normally apply expansion processing to moving picture data without causing missing of the moving picture data even when a receiver side starts storage of the moving picture data in an optical timing in the case of transmitting the moving picture data where both in-frame and inter-frame compression methods are employed. SOLUTION: A moving picture receiver 21 is provided with a storage section 204 that stores received moving picture data, an I frame detection section 206 that detects a frame compressed by using only the in-frame compression (hereinafter called I frame) from the received moving picture data, and a write sequence control section 207 that controls a write sequence of the moving picture data to the storage section 204 on the basis of a detection output of the I frame detection section 206. The storage section 204 repetitively stores the moving picture data from a head of the same storage area every time the I frame detection section 206 detects an I frame in the case of receiving no reducing request signal. Furthermore, the write sequence control section 207 records the moving picture data received continuously into areas at the outside of the storage areas in which the moving picture data are repetitively recorded when receiving the recording request signal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving image transmission system for transmitting a moving image through a wired or wireless communication line, such as a video conference system or a video telephone.

[0002]

2. Description of the Related Art A conventional moving image transmission system of this type will be described with reference to FIGS. Note that, in order to facilitate understanding, it is assumed that one-way video transmission is performed. Therefore, the description will be made separately for a transmission-only device and a reception-only device. If so, each device has both a transmission function and a reception function.

[0003] Figure 9 is a block diagram showing a configuration of a moving transmitting apparatus 1 0, FIG. 10 is a block diagram showing a configuration of a motion-picture receiving apparatus 2 0.

[0004] In FIG. 9, 3 This video transmission apparatus 1 0
Which is a wired or wireless communication line connecting between the video receiving apparatus 2 0. Reference numeral 100 denotes a moving image generating unit that generates moving image data of a camera, a video recorder, or the like, 101 denotes a moving image compression unit that compresses moving image data, 102 denotes a communication unit, 103 denotes a first switch, and 104 denotes a second switch. Both switches 103 and 104 can be switched by manual setting, for example.

[0005] A storage unit 105 includes a semiconductor memory or the like for storing compressed moving image data. The storage unit 105 is provided because the moving image data generated by the moving image generating unit 100 may not always be transmitted in real time depending on the degree of congestion of the communication line 3 or the like, so that the moving image data can be temporarily stored. That's why.

On the other hand, in FIG. 10, reference numeral 3 denotes the above communication line, 201 denotes a communication unit for receiving moving image data from the communication line 3, 202 denotes a moving image expanding unit for expanding moving image data, 20
Reference numeral 3 denotes a moving image display unit including a liquid crystal display or a CRT for displaying moving image data. Reference numeral 205 denotes a switch.

Reference numeral 204 denotes a storage unit including a semiconductor memory for storing moving image data. What provided the storage unit 204, can be seen not only displays the moving image data transmitted from the video transmission apparatus 1 0 in real time, the video as needed had been temporarily stored That's why.

Next, the operation of the conventional moving picture transmission system having the above configuration will be described below.

[0009] First, the operation of the video transmitting apparatus 1 0 side.

The moving image data obtained by the moving image generator 100 is input to a moving image compressor 101. Video compression unit 101
Performs compression for reducing the moving image data from the moving image generating unit 100 to the amount of data that can be transmitted through the communication line 3.

Here, the compression of moving image data includes intra-frame compression for compressing only within a frame, and inter-frame compression for further reducing the data amount by utilizing the correlation between the preceding and following frames. Normally, as a transmission form of a moving image via the communication line 3, H.264, which is recommended as an image encoding method for a videophone of the ITU-T standard, is used. 261, H .; As represented by H.263, intra-frame compression and inter-frame compression are used together.

[0012] More specifically, in the example shown in FIG.
The frame and the tenth frame are frames compressed using only intra-frame compression (hereinafter, referred to as I-frames), and the other frames are obtained by calculating difference information between preceding and following frames. This is a frame that has been compressed using compression (hereinafter, referred to as a P frame).

The compression mode in which the I frame and the P frame are mixed at a predetermined ratio in this manner is as follows.

Since the compression rate of the P frame is higher than that of the I frame, transmitting only the P frame can advantageously reduce the transmission bit rate per unit time. When transmission is performed, errors accumulate on the receiving side to increase the distortion of the reproduced image, and when the screen is switched and the correlation between the previous and next frames is lost, the data amount of the P frame increases instead. This is to avoid such inconveniences.

[0015] Now, when transmitting towards the video receiving apparatus 2 0 side in real time while the moving picture data compressed by video compressing section 101 from the moving image generation unit 100, first switch 103 and second switch 104 Are switched to be connected to each other. Thereby, the moving image compression unit 101
Are output from both switches 103 and 104 and the communication unit 10
The signal is output to the communication line 3 via the communication line 2.

When the moving picture data compressed by the moving picture compression section 101 is temporarily stored in the storage section 105, the first switch 103 is connected to the storage section 105. This allows
The moving image data obtained by the compression by the moving image
The information is stored in the storage unit 105 via the switch 103. Then, when transmitting the moving image data stored in the storage unit 105, the second switch 104 is connected to the storage unit 105 side. Then, the moving image data stored in the storage unit 105 is input to the communication unit 102 via the second switch 104.

The communication section 102 performs predetermined encoding and modulation on moving image data according to the type of the communication line 3 and outputs the result.

In this manner, the moving image data from the moving image generating unit 100 can be transmitted in real time via the communication line 3 and can be transmitted after being temporarily stored in the storage unit 105.

[0019] Next, the operation of the video receiver apparatus 2 0 side.

The communication section 201 receives a signal transmitted via the communication line 3, performs predetermined demodulation and decoding, and outputs compressed moving image data.

Here, when displaying the transmitted moving image data in real time, the switch 205 is connected so that the output of the communication unit 201 is connected to the moving image decompression unit 202.
Is switched. Therefore, the moving image data from the communication unit 201 is input to the moving image expanding unit 202 via the switch 205, and is expanded into the original moving image data here.

In this case, since the I frame is data obtained by the intra-frame compression processing, the I frame can be independently decompressed irrespective of the P frames before and after it. On the other hand, P
Since a frame is data obtained by an inter-frame compression process, in order to decompress the data, data obtained by processing between an I frame and a preceding and succeeding P frame is necessary. For example, in the case of FIG. 11, in order to decompress the fifth P-frame,
The I-frame of the frame, and the second to fourth frames
The P frame of the frame is required.

In this manner, the moving image data expanded by the moving image expansion unit 202 is displayed on the moving image display unit 203.

At this time, the moving image data output from the communication unit 201 is also input to the storage unit 204 at the same time. Video data is stored in the storage unit 204
Is stored.

When the moving image data stored in the storage unit 204 is displayed as an image, the switch 205 is switched so that the output of the storage unit 204 is connected to the moving image decompression unit 202. Then, the moving image data read from the storage unit 204 is input to the moving image expanding unit 202 via the switch 205 and is expanded into the original moving image data, and the expanded moving image data is displayed on the moving image display unit 203. You.

In this way, the signal received from the communication line 3 can be demodulated, decoded and decompressed and displayed in real time, and the desired compressed moving image data is stored in the storage unit 204 in response to a storage request. The stored data can be read out and displayed again.

[0027]

[SUMMARY OF THE INVENTION Incidentally, in the conventional moving image transmission system, the video receiving apparatus 2 0 side, as described above, I frames illustrated in FIG. 13 via the communication line 3 and the P-frame are mixed Moving image data is input.

[0028] Here, when transmitting the moving picture data from the video transmitting apparatus 1 0 side video receiving apparatus 2 side 0 video data in real-time, moving picture compression unit 10 of the video transmitting apparatus 1 0
From 1, because the first as compressed moving image data always starts sending from the I-frame, first will be I frames are also input to the moving image decompression unit 202 of the video receiving apparatus 2 0 side, since, Decompression processing of the compressed moving image data can be performed without any trouble.

On the other hand, since the input of the recording request signal to the storage unit 204 is generated at an arbitrary time by the operator, the storage of the moving image data in the storage unit 204 starts at an arbitrary time during the reception of the moving image data. Will be done. As a result, at the start of storing the moving image data in the storage unit 204,
There are cases where an I frame is input and a case where a P frame is input.

For example, in FIG.
If the recording request signal is given and the storage in the storage unit 204 is started at the time when the moving image data of the tenth frame happens to be output, the stored data is stored in the storage unit 2
When reading again from 04, the compressed moving image data starts from the I frame. Since this I frame is only subjected to intra-frame compression processing and not inter-frame compression processing, it is possible to normally decompress this I frame alone.

On the other hand, assuming that a recording request signal is given at the point when the moving image data of the fifth frame is accidentally output from the communication unit 201 and storage in the storage unit 204 is started, the stored moving image data When displaying,
Reading is started from the fifth frame, that is, the moving image data of the P frame.

Here, since the P frame is a frame compressed using inter-frame compression, the expansion between frames cannot be performed normally unless there is a previous frame. Therefore, the image cannot be displayed until the moving image data corresponding to the next I frame is read, that is, until the moving image data of the tenth frame is read. In other words, there is a problem that extra time is required until a desired image is displayed, and moving image data before the I-frame is read cannot be displayed and is lost.

The present invention solves the above-mentioned conventional problems. Even if the storage of moving image data is started at an arbitrary timing, if the moving image data is read out and decompressed, the lack of moving image data is eliminated. An object is to enable normal display without occurrence.

[0034]

In order to solve the above-mentioned problems, a moving picture transmission system according to the present invention is configured as follows.

(1) A moving image transmission method for transmitting moving image data using both intra-frame compression and inter-frame compression employs the following means.

Each time the receiving side detects a frame that has been compressed using only intra-frame compression, the same value is applied over the period from the detection point to the next detection of a frame compressed using only intra-frame compression. The moving image data is repeatedly stored in the storage area, and when a request to start recording of the moving image data being received is issued, the moving image data is repeatedly stored from the storage area to the area outside the area. The sequentially received moving image data is continuously recorded.

(2) The following means is adopted in a moving image transmission system for transmitting moving image data using both intra-frame compression and inter-frame compression via a communication line.

A moving image receiving apparatus for receiving moving image data through the communication line, the moving image receiving apparatus storing a moving image data received from the moving image data, and compressing the received moving image data using only intra-frame compression. An I-frame detection unit for detecting a frame which has been recorded, and a writing order control unit for controlling a writing order of the moving image data to the storage unit based on a detection output of the I-frame detection unit. If no request signal is input, the I
Moving image data is repeatedly stored in the same storage area over the period from when the frame detection unit detects a frame compressed using only intra-frame compression to when the next frame compressed using only intra-frame compression is detected When the recording request signal is input, the writing order control unit continuously records the moving image data sequentially received from the storage area where the moving image data is repeatedly recorded over an area outside the storage area. It is characterized by that.

According to these configurations, even when the storage of the moving image data is started at an arbitrary timing on the receiving side, the compressed moving image data can be normally expanded without any loss.

[0040]

Embodiments of the present invention will be described below.

According to the moving image transmission method of the present invention, when transmitting moving image data using both intra-frame compression and inter-frame compression, the receiving side detects a frame compressed in advance using only intra-frame compression. Each time, the moving image data is repeatedly stored in the same storage area for a period from the time of detection to the next detection of a frame compressed using only intra-frame compression. When a request to start recording is issued, moving image data sequentially received from a storage area in which moving image data is repeatedly recorded over an area outside the storage area is continuously recorded.

According to the moving image transmission method of the present invention, when transmitting moving image data using both intra-frame compression and inter-frame compression, the moving image data is transmitted from the transmitting side to the receiving side. In the case where a request to start recording of the received moving image data is issued, the receiving side informs the transmitting side of the recording request, and the transmitting side responds to the request by using the moving image data compression method. Is forcibly changed, and transmission of moving image data is restarted from a frame compressed using only intra-frame compression.

In the moving image transmission method according to the third aspect, when transmitting moving image data using both intra-frame compression and inter-frame compression, moving image data stored in advance on the transmitting side is read and transmitted to the receiving side. If a request to start recording of the received moving image data is issued on the receiving side, the receiving side notifies the transmitting side of the recording request to the transmitting side, and the transmitting side responds accordingly. In addition, reading of moving image data is restarted from a storage position of a frame compressed using only intra-frame compression positioned temporally before or after the recording request is issued.

According to a fourth aspect of the present invention, there is provided a moving image receiving apparatus for receiving moving image data through a communication line when transmitting the moving image data using both intra-frame compression and inter-frame compression through a communication line. The moving image receiving apparatus has a storage unit that stores received moving image data, an I-frame detecting unit that detects a frame compressed from the received moving image data using only intra-frame compression,
A writing order control unit that controls a writing order of the moving image data to the storage unit based on a detection output of the I frame detection unit, wherein the storage unit includes: The moving image data is stored in the same storage area for a period from when the I-frame detection unit detects a frame compressed using only intra-frame compression to when a frame compressed using only intra-frame compression is next detected. When a recording request signal is input, the writing order control unit reads the moving image data sequentially received from the storage area where the moving image data is repeatedly recorded over an area outside the storage area. It is characterized by recording continuously.

According to a fifth aspect of the present invention, in the moving image transmission system, when transmitting moving image data using both intra-frame compression and inter-frame compression via a communication line, the moving image transmission device transmits the moving image data via the communication line. And a moving image receiving device that receives moving image data, the moving image receiving device stores a received moving image data, and in response to a request for storing moving image data to the storage unit, A moving image transmitting device, the moving image compressing unit compressing moving image data, and a moving image in the moving image compressing unit in response to an instruction signal from the instruction unit on the moving image receiving device side. A compression control unit that changes a data compression method, wherein the moving image compression unit performs only intra-frame compression based on a control signal of the compression control unit when the instruction signal is received. Create a frame that has been compressed have,
It is characterized in that moving image data is transmitted starting from this frame.

According to a sixth aspect of the present invention, in the moving image transmission system, when transmitting moving image data using both intra-frame compression and inter-frame compression via a communication line, the moving image transmission device transmits the moving image data via the communication line. And a moving image receiving device that receives moving image data, the moving image receiving device stores a received moving image data, and in response to a request for storing moving image data to the storage unit, A moving image transmitting apparatus, the moving image transmitting apparatus includes a moving image compressing unit that compresses moving image data, and a storing unit that stores the moving image data compressed by the moving image compressing unit.
A reading order control unit that changes a reading order of moving image data in the storage unit according to an instruction signal from the instruction unit on the receiving device side, wherein the reading order control unit responds to the instruction signal, Regarding the moving image data stored in the storage unit, the reading of the moving image data is started from the storage position of the frame compressed by using only the intra-frame compression temporally located before or after the time when the recording request is issued. It is characterized by restarting.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. In this embodiment,
For ease of understanding, it is assumed that one-way video transmission is performed, and therefore, a description will be given separately for a transmission-only device and a reception-only device, but the present invention is not limited to this. However, the present invention can be applied to a case where bidirectional video transmission is performed. In that case, each device has both a transmission function and a reception function.

(Embodiment 1) FIG. 1 is a block diagram showing a configuration of a moving image receiving apparatus in a moving image transmission system according to Embodiment 1 of the present invention, and portions corresponding to those of the conventional example shown in FIG. Is assigned. Note that the configuration of the moving image transmitting apparatus is the same as that of the conventional example shown in FIG.

[0049] In FIG. 1, 2 1 shows the overall video receiving device, 3 a communication line, 201 communication unit for receiving video data from the communication line 3, moving image expanding section for expanding the video data 202, 203 A moving image display unit for displaying moving image data, a storage unit 204 for storing moving image data, and a switch 205 are the same as those in the conventional example shown in FIG.

The feature of the first embodiment is that the communication unit 201
, An I-frame detecting unit 206 for detecting the I-frame of the moving-image data output from the CPU, and writing for controlling the order of writing the moving-image data to the storage unit 204 according to the detection output of the I-frame detecting unit 206 Order control unit 207
Is provided. When the moving image data is stored in the storage unit 204, a recording request signal is input to the I-frame detection unit 206 in response to an operation of a manual switch (not shown) or the like.

Next, the operation of the video transmission system of the first embodiment, especially mainly the operation of the video receiver apparatus 2 1 will be described with reference to a memory map diagram of Figure and the timing chart of FIG 3. Note that FIG. 2 shows a compression mode in which one frame of I frame is mixed with eight frames of P frame for convenience of description, but the present invention is not limited to this. . In FIG. 3, the start address for storing the moving image data is assumed to be address a.

[0052] In video reception device 2 1, when this case is displayed in real time video data to the video display unit 203, as the output of the motion-picture receiving apparatus 2 first communication unit 201 is connected to the video decompression unit 202 Switch 205
Are switched, and the I-frame detection unit 20
No. 6 is in a state where the recording request signal has not been input yet.

In this state, when the signal transmitted via the communication line 3 is received by the communication unit 201, the communication unit 20
1 performs predetermined demodulation and decoding of this signal, and then outputs compressed moving image data. Then, the moving image data from the communication unit 201 is transmitted to the moving image
02 and is expanded to the original moving image data here.
This operation is the same as the conventional case.

Further, the moving image data output from the communication unit 201 is input to the storage unit 204 and also to the I-frame detection unit 206.

The I frame detecting section 206 detects an I frame included in the compressed moving image data, and outputs a detection signal to the writing order control section 207 every time the I frame is detected. For example, in FIG. 2, the first frame and the tenth frame are each an I frame, and thus a detection signal is output to the writing order control unit 207 at this timing.

The write order control unit 207 controls the storage order when storing the moving image data in the storage unit 204 in response to the I frame detection signal from the I frame detection unit 206 each time. That is, each time the detection signal is input from the I-frame detection unit 206, the writing order control unit 207 performs the writing control so that the writing start position when storing the moving image data in the storage unit 204 becomes the same position. I do.

For example, specifically, as shown in FIG.
Assuming that the I-frame moving image data is received in the first and tenth frames, respectively, as shown in FIG. If the I-frame moving image data of the frame is written, thereafter, since the second to ninth frames are P-frame moving image data, no detection signal is output from the I-frame detecting unit 206, and therefore, the storage unit In 204, P-frame moving image data is sequentially stored from address (a + 1) to address (a + 8).

Next, at the tenth frame, since the moving picture data is an I frame, a detection signal is output from the I frame detecting section 206.
Controls the storage address in response to the detection signal so that the storage unit 204 starts storage from the first address a again. Therefore, the storage unit 204 stores the moving image data of the 10th I-frame at the first address a and thereafter (a +
1) In the range from address to address (a + 8), moving image data of P frames from the eleventh frame to the nineteenth frame are sequentially overwritten and stored.

The above operation is repeated until a recording request signal is input.

[0060] In the moving receiving device 2 1, when storing the video data in the storage unit 204 when storing the moving image data temporarily in the storage unit 204, the recording request signal is input to the I-frame detector 206. For example, in FIG. 2, when a recording request signal is input at a timing at which a fifth P-frame is received, the I-frame detection unit 206 stops the I-frame detection operation according to the recording request signal.

Therefore, to the I frame detecting section 206, after the recording request signal is inputted in the fifth frame, the moving image data of the I frame is inputted in the tenth frame. However, the I frame detection unit 206 does not output a detection signal to the writing order control unit 207. For this reason, the writing order control unit 207 does not perform such control as to make the writing start positions of the moving image data the same.

As a result, the data being written is stored in the storage unit 204 as it is while sequentially changing the writing position. That is, when the moving image data of the ninth P frame is stored at the address (a + 8), the moving image data of the I frame of the tenth frame is stored at the next address (a + 9), and then (a + 10). The address P) stores the moving image data of the P-th frame of the eleventh frame. Thereafter, while the recording request signal is being input, the storage is continuously performed in the storage unit 207 while sequentially changing the write address.

Therefore, looking at the contents of the moving image data stored in the storage unit 204, the storage unit 204 shows that the recording request signal is generated at the input timing of the moving image data of the fifth frame. Before the recording request signal is generated, from the first frame I-frame moving image data to the fourth frame P-frame moving image data is continuously stored from the first address a to the address (a + 4). Will be. And, for example, in FIG.
When the input of the recording request signal is released at the timing when the 16th P-frame is received, the storage unit 2
As shown in FIG. 3, the 15th frame P-frame moving image data immediately before the recording request signal is input
That is, it is stored at the address (a + 14).

When the input of the recording request signal is released, the I frame detecting section 206 starts the I frame detecting operation again. In this case, the I-frame detecting unit 206 outputs the I-frame of the next twentieth frame after the input of the recording request signal is released.
Until the moving image data of the frame is detected, a signal to inhibit writing of the moving image data is sent to the writing order control unit 207. Therefore, the writing order control unit 207 starts storing the moving image data from the address (a + 15) in the storage unit 204 only when the moving image data of the next I-th frame of the twentieth frame is detected. . Thereafter, as in the case of the description of the operation, the storage unit 204 stores the moving image data from the address (a + 15) to the address (a + 23) from the input of the I frame until the input of the next I frame. The operation is performed so as to sequentially store data between the two.

As described above, in the first embodiment, as can be understood from the above description of the operation, even if the storage is started from an arbitrary time, the storage up to the I frame prior to the frame required for the expansion of the moving image data is performed. Video data is stored in the storage unit 204
Next, when the moving image data stored in the storage unit 204 is read again and displayed, the moving image decompressing unit 202 always stores the moving image data from the I frame preceding the frame at the start of storage. Since input is performed, expansion based on these moving image data can be performed normally.

(Embodiment 2) FIG. 4 is a block diagram showing a configuration of a moving image receiving apparatus in a moving image transmission system according to Embodiment 2 of the present invention, and FIG. 5 is a block diagram showing a configuration of a moving image receiving apparatus of the moving image transmission system. FIG. 9 and FIG.
Parts corresponding to those of the conventional example shown in FIG.

[0067] In FIG. 4, 1 2 shows the overall video transmission device, 3 a communication line, video generator 100 for generating the moving image data, 101 is moving picture compression unit for compressing the video data, 102 is a communication unit, 103 is a first switch, 104
Is a second switch, and 105 is a storage unit for storing compressed moving image data. The configuration of these is the same as that of the conventional example shown in FIG.

[0068] Further, in the moving transmitting device 1 2 according to the second embodiment, instruction detecting unit 1 for detecting a timing indication signal transmitted from the output of the communication unit 102 from the moving picture reception apparatus 2 2
06, and a compression control unit 107 that controls a method of compressing moving image data in the moving image compression unit 101 based on the detection output of the instruction detection unit 106. Also, based on a detection output of the instruction detecting unit 106, a reading order control unit 108 that controls a reading order of data read from the storage unit 105.
Is provided.

[0069] On the other hand, in FIG. 5, 2. 2 shows the overall video receiving device, 3 a communication line, 201 communication unit for receiving video data from the communication line 3, 202 moving image expanding section for expanding video data, 203 is a moving image display unit for displaying moving image data, 204 is a storage unit for storing moving image data, 205
Are switches, and their configurations are the same as those of the conventional example shown in FIG.

[0070] In the motion-picture receiving apparatus 2 2 according to the second embodiment, furthermore, video transmission device of FIG. 4 via the communication unit 201 based on the recording request signal input in response to the operation of such an unshown manual switch A timing instruction unit 208 for transmitting a timing instruction signal toward the 12 side is provided. When the moving image data is stored in the storage unit 204, the recording request signal is input not only to the timing instruction unit 208 but also to the storage unit 204 at the same time.

Next, the operation of the moving picture transmission system according to the second embodiment will be described with reference to a timing chart shown in FIG.
This will be described with reference to the memory map diagrams shown in FIGS.

[0072] The basic operation of the moving transmitter 1 2 and motion-picture receiving apparatus 2 2 in this case when displaying in real time the video data to the video display unit 203 of the video receiving apparatus 2 2, shown in FIGS. 9 and 10 This is basically the same as the conventional apparatus.

[0073] That is, moving image compression unit 101 of the moving picture transmission apparatus 1 2, as shown in FIG. 11, compressed form of percentage, such as I-frame of one frame relative to the P-frame of 8 frames is mixed To compress the video data. Then, the compressed moving image data is transmitted to the first and second switches 1.
It is outputted to the video receiving apparatus 2 2 via the communication line 3 from 03,104 and a communication unit 102.

[0074] The communication unit 201 of the video receiving apparatus 2 2 receives the signal transmitted via the communication line 3 predetermined demodulation, and outputs the moving picture data compressed by performing the decoding, which switch The image data is input to the moving image decompression unit 202 through the storage unit 204 via the storage unit 204.

The moving picture decompressing section 202 displays the decompressed moving picture data on the moving picture display section 203 in order to decompress the compressed moving picture data to the original moving picture data.

On the other hand, since the recording request signal is not input to the storage unit 204, no moving image data is recorded in the storage unit 204.

[0077] If the case of storing the moving image data in the storage unit 204 of the video receiving apparatus 2 2, (a) moving the transmission device 1 2 of the video compression portion 101
And when storing in the storage unit 204 in the moving image data is compressed and transmitted toward the video receiving apparatus 2 2 as it is,
(b) reads out the moving image data stored in advance in the video transmission apparatus 1 2 in the storage unit 105, which was transmitted to the video reception apparatus 2 2 two cases when stored in the storage unit 204 Therefore, each will be described.

[0078] (a) moving the transmission device 1 2 of the video compression portion 101
In this case if the moving image data is compressed and transmitted toward the video receiving apparatus 2 2 directly stored in the storage unit 204, the video transmission apparatus 1 2 side smell advance first, second switch 103 , 104 are switched so as to be connected to each other, and the storage unit 105 and the communication unit 10 are connected.
2 has been disconnected.

[0079] Further, in the video receiver apparatus 2 2 side, by the operation of such an unillustrated manual switch, when the recording request signal is generated, the recording request signal is input to the timing instruction section 208 and a storage unit 204 You.

[0080] Depending on the input of the recording request signal, the timing instructing unit 208, toward the video transmission apparatus 1 2 side of FIG. 4 through the communication unit 201 sends toward the timing instruction signal to the video transmission apparatus 1 2 I do.

[0081] In the video transmitting apparatus 1 2, a timing signal sent from the video receiving device 2 2 side communication unit 10
When the signal is received at step 2, this timing instruction signal is output to the instruction detection unit 106.

When the instruction detecting section 106 detects this timing instruction signal, it outputs a detection signal to the compression control section 107.

When the detection signal is input, the compression control section 107 outputs a control signal for changing the compression method to the moving image compression section 101.

Here, when there is no control signal for changing the compression method from the compression control unit 107, the moving image compression unit 101, as shown in FIG. Moving image data is generated at such a rate that I frames for each minute are mixed, but when a control signal is input from the compression control unit 107, an I frame is forcibly generated at the time of input, and thereafter, again, At predetermined intervals I
Generate a frame.

For example, as shown in FIG. 11, when there is no control signal from compression control section 107, when an I-frame is generated in the first frame, the next I-frame is generated in the tenth frame. Generation will be performed.

[0086] However, if at the time of compressing the moving picture data of the fifth frame, the timing instruction signal based on the recording request signal from the video receiving device 2 2 side is output, FIG. 6
As shown in (5), the moving image compression section 101 generates an I frame at the fifth frame receiving this timing instruction signal. Then, after that, the moving image data of the P frame is used for the eight frames from the sixth frame to the thirteenth frame,
In the next 14th frame, I-frame moving image data is output. That is, after the I frame is forcibly generated at the time when the recording request signal is input, the I frame is generated at a predetermined interval until the recording request signal is released.

[0087] In this way, since the video transmission apparatus 1 2 side first video data of the I-frame in response to the recording request signal is generated, the video receiving apparatus 2 2 side, the storage unit in response to the recording request signal When the storage is started at 204, the I frame is always received first. As a result, as shown in FIG. 7, the storage unit 204 always stores the I-frame moving image data at the first address a.

When the moving image data is read from the storage unit 204, the moving image data is read from the first stored address a. Therefore, in the moving image decompression unit 202, the moving image data is read first. Since the moving image data from the I frame is expanded, the expansion can always be performed normally.

[0089] (b) reads out the moving image data stored in advance in the video transmission apparatus 1 2 in the storage unit 105, which in this case when storing to the storage unit 204 transmitted to the video reception apparatus 2 2 to a moving transmitting device 1 2 side smell, pre-second
Switch 104 is switched so that the storage unit 105 and the communication unit 102 are connected.

[0090] Further, in the video receiver apparatus 2 2 side, as in the case of the (a), by the operation of such an unillustrated manual switch, when the recording request signal is generated, the recording request signal timing indication Unit 208 and storage unit 204
Respectively.

[0091] Depending on the input of the recording request signal, the timing instructing unit 208, toward the video transmission apparatus 1 2 side of FIG. 4 through the communication unit 201 sends toward the timing instruction signal to the video transmission apparatus 1 2 I do.

[0092] In the video transmitting apparatus 1 2, a timing signal sent from the video receiving device 2 2 side communication unit 10
When the signal is received at step 2, this timing instruction signal is output to the instruction detection unit 106.

When the instruction detecting section 106 detects this timing instruction signal, it outputs the detection signal to the reading order control section 108 together with the compression control section 107.

When receiving this detection signal, read order control section 108 outputs a control signal to storage section 105 to change the read position of the stored data.

For example, as shown in FIG.
In No. 5, it is assumed that the moving image data of the I frame is stored in advance at the first address b and the moving image data of each frame is sequentially stored, and the moving image data from the address b to the address (b + 3) has already been read. point, if the timing indication signal based on the recording request signal from the video receiving device 2 2 side is input, the read sequence control unit 108, instruction detecting unit 106
Based on the detection signal from, the reading of the moving image data is started not from the next address (b + 4) but from the first address b. That is, when the timing instruction signal based on the recording request signal is input, the reading order control unit 108 always returns to the first address b of the storage unit 105 and starts reading the moving image data.

[0096] In this way, since the video transmission apparatus 1 2 side first video data of the I-frame in response to the recording request signal is generated, the video receiving apparatus 2 2 side, the storage unit in response to the recording request signal When the storage is started at 204, the I frame is always received first. As a result, as shown in FIG. 7, the storage unit 204 always stores the I-frame moving image data at the first address a.

When the moving image data is read from the storage unit 204, the moving image data is read from the first stored address a. Therefore, the moving image decompressing unit 202 reads the moving image data first. Since the moving image data from the I frame is expanded, the expansion can always be performed normally.

[0098]

According to the present invention, the following effects can be obtained.

(1) According to the first and fourth aspects of the present invention, prior to storing moving image data, the next I
Since the compressed moving image data up to the frame is repeatedly recorded, even if the storage is started at the time when the P frame is transmitted, when the stored moving image data is read out and displayed again, the frame at the time of the storage start is read. Since the moving image data can be read from the previous I frame temporally, the compressed moving image data at the time when the storage is started can be normally expanded without loss.

(2) According to the second and fifth aspects of the present invention, at the start of storage of moving image data, an instruction signal corresponding to a storage request is transmitted from the receiving side to the transmitting side, and the transmitting side transmits the instruction signal based on the instruction signal. Since the I-frame is forcibly generated by changing the compression method of the moving image data, the storage always starts from the I frame even if the receiving side starts storing the moving image data at an arbitrary timing. Therefore, when reading out and displaying the moving image data thus stored again,
Decompression can be performed normally without loss of the compressed moving image data.

(3) According to the third and sixth aspects of the present invention, when a storage request is issued on the receiving side while reading the moving image data stored in advance on the transmitting side, this is In response, the receiving side transmits an instruction signal to the transmitting side, and the transmitting side changes the reading position of the stored data based on the instruction signal and always resumes reading the moving image data from the previous I frame. Even if the storage of the moving image data starts at an arbitrary timing on the side, the storage always starts from the I frame. Therefore, when the stored moving image data is read again and displayed, the compressed moving image data can be normally expanded without loss.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a moving image receiving device of a moving image transmission system according to Embodiment 1 of the present invention.

FIG. 2 is a timing chart showing a relationship between compressed moving image data and a recording request signal according to the first embodiment of the present invention;

FIG. 3 is a memory map diagram showing a state where compressed moving image data is stored in a storage unit of the moving image receiving device in the first embodiment of the present invention.

FIG. 4 is a block diagram illustrating a configuration of a moving image transmission device of a moving image transmission system according to Embodiment 2 of the present invention.

FIG. 5 is a block diagram illustrating a configuration of a moving image receiving device of the moving image transmission system according to the second embodiment of the present invention.

FIG. 6 is a timing chart illustrating a relationship between moving image data output from a moving image compression unit and a recording request signal according to the second embodiment of the present invention;

FIG. 7 is a memory map diagram showing a state where compressed moving image data is stored in a storage unit of the moving image receiving device in the second embodiment of the present invention.

FIG. 8 is a memory map diagram showing a state in which compressed moving image data is stored in a storage unit of the moving image transmitting device in the second embodiment of the present invention.

FIG. 9 is a block diagram illustrating a configuration of a moving image transmission device of a conventional moving image transmission system.

FIG. 10 is a block diagram showing a configuration of a moving image receiving device of a conventional moving image transmission system.

FIG. 11 is a timing chart showing a generation state of compressed moving image data in a conventional moving image transmission system.

[Explanation of symbols]

1 2 moving image transmitting device 2 1 , 2 2 moving image receiving device 3 communication line 100 moving image input unit 101 moving image compression unit 102, 201 communication unit 103, 104, 205 switch 105, 204 storage unit 106 instruction detection unit 107 compression control unit 108 read Order control unit 202 Moving image expansion unit 203 Moving image display unit 206 I frame detection unit 207 Writing order control unit 208 Timing instruction unit

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Kazuki Takamune 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. F term (reference) 5C053 FA27 GB21 GB29 KA04 KA08 KA19 KA24 LA14 5C059 KK00 MA00 MA05 PP05 PP06 RA01 RA04 SS07 TA00 TA18 TC45 UA02 UA05 UA37 UA38

Claims (6)

[Claims]
1. A moving image transmission method for transmitting moving image data using both intra-frame compression and inter-frame compression, the method comprising: detecting a frame that has been compressed using only intra-frame compression on the receiving side; The moving image data is repeatedly stored in the same storage area for a period from the point in time until the next frame compressed using only intra-frame compression is detected, and a request to start recording of the received moving image data is issued. A moving picture transmission method comprising: when received, continuously recording moving picture data sequentially received from a storage area in which the moving picture data is repeatedly recorded over an area outside the storage area.
2. A moving image transmission method for transmitting moving image data using both intra-frame compression and inter-frame compression, wherein during transmission of moving image data from a transmitting side to a receiving side,
When a request to start recording of the received moving image data is issued on the receiving side, the receiving side notifies the transmitting side of the recording request, and the transmitting side responds to the request by recording the moving image data. A moving image transmission method characterized by forcibly changing a compression method and restarting transmission of moving image data starting from a frame compressed using only intra-frame compression.
3. A moving image transmission method for transmitting moving image data in which both intra-frame compression and inter-frame compression are used, wherein the transmitting side reads out moving image data stored in advance and transmits the moving image data to the receiving side. In the case where a request to start recording of the received moving image data is issued, the receiving side informs the transmitting side of the recording request, and the transmitting side responds accordingly to the recording request. A moving picture transmission method characterized by resuming reading of moving picture data starting from a storage position of a frame compressed using only intra-frame compression temporally located before or after the output point in time.
4. A moving image transmission system for transmitting moving image data using both intra-frame compression and inter-frame compression via a communication line, comprising: a moving image receiving device for receiving the moving image data through the communication line. The apparatus includes a storage unit for storing the received moving image data, an I-frame detecting unit for detecting a frame compressed from the received moving image data using only intra-frame compression, and a detection output of the I-frame detecting unit. A writing order control unit that controls an order of writing moving image data to the storage unit, wherein the storage unit performs only the intra-frame compression when the recording request signal is not input. The same description is used for the period from the point when the frame compressed using the intra-frame compression is detected until the next frame compressed using only the intra-frame compression is detected. When the recording request signal is input, the writing order control unit extends from the storage area where the moving image data is repeatedly recorded to an area outside the area. A moving image transmission system for continuously recording moving image data sequentially received.
5. A moving image transmission system for transmitting moving image data via a communication line using both intra-frame compression and inter-frame compression, and a moving image transmitting apparatus transmitting the moving image data via the communication line and receiving the moving image data. A moving image receiving device, wherein the moving image receiving device transmits the recording request to the moving image transmitting device side in response to a request for storing moving image data in the storage unit, which stores the received moving image data. A moving image compression device that compresses moving image data, and changes a method of compressing moving image data in the moving image compression unit in response to an instruction signal from the instruction unit on the moving image receiving device side. A compression control unit that performs compression using only intra-frame compression based on a control signal of the compression control unit when the instruction signal is received. Video transmission system to create a frame, which performs a transmission of moving image data of this frame as a starting point, and wherein the.
6. A moving image transmission system for transmitting moving image data via a communication line using both intra-frame compression and inter-frame compression, and a moving image transmitting apparatus transmitting the moving image data via the communication line and receiving the moving image data. A moving image receiving device, wherein the moving image receiving device transmits the recording request to the moving image transmitting device side in response to a request for storing moving image data in the storage unit, which stores the received moving image data. The moving image transmitting apparatus includes a moving image compressing unit that compresses moving image data, a storing unit that stores moving image data compressed by the moving image compressing unit, and a moving unit that transmits the moving image data. A reading order control unit that changes a reading order of the moving image data in the storage unit according to an instruction signal, wherein the reading order control unit stores the moving image data in the storage unit according to the instruction signal. For the stored moving image data, reading of the moving image data is resumed starting from the storage position of the frame compressed using only intra-frame compression positioned temporally before or after the recording request is issued. A moving image transmission system, characterized in that:
JP25678499A 1999-09-10 1999-09-10 Method and system for moving picture transmission Pending JP2001086511A (en)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003041341A1 (en) * 2001-11-05 2003-05-15 Matsushita Electric Industrial Co., Ltd. Server apparatus and terminal apparatus used in video transmission system
JP2007060351A (en) * 2005-08-25 2007-03-08 Nec Personal Products Co Ltd Video telephone system, and video data processing method in video telephone system
CN100377586C (en) * 2002-03-08 2008-03-26 松下电器产业株式会社 Video recorder
JP2011066944A (en) * 2011-01-04 2011-03-31 Nec Personal Products Co Ltd Video telephone system, and video data processing method in video telephone system

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2003041341A1 (en) * 2001-11-05 2003-05-15 Matsushita Electric Industrial Co., Ltd. Server apparatus and terminal apparatus used in video transmission system
CN1314236C (en) * 2001-11-05 2007-05-02 松下电器产业株式会社 Server apparatus and terminal apparatus used in video transmission system
CN100377586C (en) * 2002-03-08 2008-03-26 松下电器产业株式会社 Video recorder
JP2007060351A (en) * 2005-08-25 2007-03-08 Nec Personal Products Co Ltd Video telephone system, and video data processing method in video telephone system
JP2011066944A (en) * 2011-01-04 2011-03-31 Nec Personal Products Co Ltd Video telephone system, and video data processing method in video telephone system

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