JP2002027478A - Image information encoding apparatus and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently perform the inverse reproduction. SOLUTION: A reproduction terminal 120 has a special reproduction control unit 102, an encoder 105, a memory medium 107, a reading unit 109, a data transformation unit 108 and a decoder 110. The encoder 105 encodes a video source signal 104 by using an intra encoded image (picture I), and a two-way predictive encoded image (picture B). The reading unit 109 and the data transformation unit 108 perform the inverse reproduction according to a control signal from the special reproduction control unit 102.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for decoding and displaying encoded image compression information, distributing image compression information via a network, and receiving the image compression information at a decoding terminal.
Image information encoding apparatus and method, image information conversion apparatus and method, image information decoding apparatus and method, image information decoding apparatus and method, image information distribution apparatus and method that are optimally used when performing special reproduction in a data distribution system that decodes and displays the data And media.

[0002]

2. Description of the Related Art Conventionally, DVD (digital versatile / vid)
A playback terminal that encodes, stores, decodes, and displays a video signal on an eo disc) or a hard disk is provided. The playback terminal includes, for example, an encoding unit that encodes a video source signal into video data, a recording medium that stores video data, a reading unit that reads video data from the recording medium, and a data conversion unit that converts video data. , A decoding unit for decoding video data, and a special reproduction control unit for controlling special reproduction such as reverse reproduction and pause.

[0003] An input video source signal is encoded into video data by an encoding unit and stored in a storage medium. The video data stored in the recording medium is read by the reading unit and sent to the decoding unit. The video data decoded by the decoding unit is displayed by a display terminal (not shown). Note that a reproduction-only terminal may not include an encoding unit.

[0004] When performing special reproduction such as reverse reproduction or pause, the special reproduction control unit controls the reading unit and the decoding unit in accordance with the user's special reproduction designation input. That is, the reading unit reads out only the data necessary for the specified trick play from the storage medium under the control of the trick play control unit. For example, in fast-forward playback, the reading unit skips data not used for decoding and display, and sends only necessary data to the decoding unit.

[0005] As an encoding method of video data in a reproduction terminal, for example, ISO / IEC13818-2 (so-called MPEG-2
video). The encoding method of video frames of ISO / IEC13818-2 includes an intra-coded image (I picture) that is encoded only from intra-frame data,
A forward (forward) predicted coded image (P picture) to be coded using prediction from the previous frame, and a bidirectional prediction code coded using prediction from preceding and following (forward and reverse) frames There is a coded image (B picture). Because this coding scheme uses prediction between frames,
Processing for performing reverse reproduction, among other special reproductions, becomes complicated.

Here, a description will be given of a process for reversely reproducing video data encoded according to ISO / IEC13818-2. FIG.
To the time of reverse reproduction, showing a case of decoding the B-picture B ₁₁ as a specific example. In the figure, I represents an I picture, P represents a P picture, and B represents a B picture.

In the first step S900, I₁₂Already
It is assumed that it has been decrypted. B₁₁To decrypt
Refer to the previous or next I or P picture as the prediction source picture.
Need to be illuminated. That is, I₁₂And P₉Is decrypted
It is necessary to be. To decode a P picture
The P picture or I picture which is the prediction source picture
Is required, but it is
Source picture has not yet been decoded.
No. Therefore, in step S901, P₉Decrypt
To be the next I picture in the reverse playback direction.
₀Is detected and decrypted. Then, in step S902,
And the decrypted I₀Based on B₁₁Necessary to decrypt
P₉P which is all P pictures up to_Three, P₆, P₉Sequentially
Decrypt. In step S903, the decrypted P₉
Using P₉And I₁₂Based on B ₁₁Is decrypted. this
Thus, when performing reverse playback, the order of encoding and decoding
Because the order is reversed, one picture can be decoded.
Many pictures must be decoded beforehand.
No.

[0008] The reading section and the decoding section of the playback terminal must pre-read and decode a large number of pictures as described above when performing reverse playback. Therefore, since a large number of pictures must be decoded at the time interval for displaying one picture, a high-speed decoding unit is required. As described above, when there is no ability to decode a plurality of pictures at high speed, there is a method of extracting and decoding only I pictures in video data. However, if the B picture and the P picture between the I pictures are lost, the reversely reproduced image to be decoded becomes a frame feed. Furthermore, the reading unit and the decoding unit of the playback terminal require an extra frame memory for storing the prediction source picture. Alternatively, every time a B picture is decoded, decoding must be repeated from the I picture immediately after.

Next, a description will be given of a conventional system for distributing the stored video data to the decoding terminal 117 via the transmission medium 115 instead of decoding and displaying the video data.

This system comprises a server 100 and a decoding terminal 117, which are connected by a transmission medium 115. The server 100 includes an encoding unit 105, a storage medium 107, a reading unit 109, and a decoding unit 110
, A re-encoding unit 112, a transmission unit 114, and a special reproduction control unit 102. The decoding terminal 117 includes a receiving unit 118 and a decoding unit 119.

[0011] The server 100 stores the video data 106 in the storage medium 107, and transmits the video data 106 as distribution data 116 to the decoding terminal 117 via the transmission medium 115 by the transmission unit 114. The decoding terminal 117 receives the distribution data 116 by the receiving unit 118, decodes the distribution data by the decoding unit 119, and displays the decoded data by a display unit (not shown).

When performing special reproduction such as reverse reproduction or pause, the user inputs a special reproduction designation input 101 to the special reproduction control unit 102. In the case of performing special reproduction in the data distribution system as shown in FIG. 10, in order for the decoding unit 119 of the decoding terminal 117 to perform the same special reproduction decoding processing as the reproduction unit of the reproduction terminal described above, special decoding for special reproduction is performed. A distribution method for the distribution data is required. For example, in the example of the reverse reproduction shown in FIG. 9, all the pictures (I ₀ , P ₃ , P ₆ , P ₉ ) necessary for decoding the B picture B ₁₁ are converted to B pictures.
_The distribution must be performed by the _eleventh decoding time, and the distribution data rate locally increases. In order to perform distribution in a special data format for trick play, the transmission medium 11
5. The receiving unit 118 and the decoding unit 119 must support a special data format for special reproduction. This problem,
The trick play can be avoided by a method in which the server 100 converts video data for trick play according to a request before distribution.

A conventional data distribution system compatible with trick play as shown in FIG. 10 has a reading unit 109 for reading video data in accordance with the designation of trick play and decoding video data as performed in a playback terminal. Decryption unit 11
In addition to 0, data conversion can be performed by the re-encoding unit 112 that re-encodes the decoded data. Converted video data 113 output by re-encoding section 112
Becomes data in which the result of the trick play has been reflected. However, since the decoding unit 110 and the re-encoding unit 112 re-encode the video data, the processing load is large and the image quality may be degraded. Further, the processing delay involved in the data conversion increases, and as a result, the delay from the input of the trick play designation input 101 to the actual display of the trick play on the decoding terminal 120 increases.

[0014]

As described above, when the playback terminal decodes video data using an encoding method using inter-frame prediction, when performing reverse playback,
A plurality of pictures must be decoded in advance to decode one picture. Therefore, high-speed processing is required to pre-read and decode a large number of pictures while displaying one picture in the reading unit and the decoding unit of the playback terminal. Further, an extra frame memory is required to store the prediction source picture. Alternatively, every time a B picture is decoded, decoding must be repeated from the I picture immediately after. As described above, reverse reproduction cannot be performed by the same decoding processing as normal reproduction.

In a conventional data distribution system, stored video data is distributed by a server to a decoding terminal via a transmission medium. For this reason, a special distribution data distribution method for special reproduction is required, and there is a problem that the transmission medium, the receiving unit, and the decoding unit must support a special data format for special reproduction. In order to avoid this problem, a method of distributing video data converted by the server for special reproduction according to a request at the time of special reproduction can be considered. However, this method has a problem that the processing load is large and the image quality is deteriorated because it is necessary to re-encode the video data in the server. Also,
There is a problem that the processing delay for the data conversion increases, and as a result, the delay from the input of the trick play designation input to the actual display of the trick play on the decoding terminal increases.

The present invention has been proposed in view of the above situation, and has an image information encoding apparatus and method capable of reducing the processing load at the time of performing special reproduction and, in particular, efficiently performing reverse reproduction. It is an object of the present invention to provide an image information conversion apparatus and method, an image information decoding apparatus and method, an image information distribution apparatus and method, and a medium.

[0017]

In order to solve the above-mentioned problems, the present invention encodes image information.
An intra-coding method that encodes an image within an image, and a prediction code that predicts and encodes an image with reference to another image and that can be decoded by simply reversing the prediction direction when the display order is reversed. In this method, image information is encoded into image compression information using an encoding method.

The present invention converts image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image. The images are rearranged in the reverse order of the display order of the image compression information, and are converted so that the prediction directions are also switched according to the replacement of the prediction source image referred to by the encoded image.

The present invention decodes image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image. Image compression information in which an image is rearranged in the reverse order to the display order of the image compression information is input, and the prediction direction is also switched according to the replacement of the prediction source image referred to by the encoded image, and decoding is performed. is there.

The present invention distributes image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image. The images are rearranged in the reverse order of the display order of the image compression information, converted so that the prediction direction is also changed according to the change of the prediction source image referred to by the encoded image, and converted by the conversion unit. It distributes image compression information.

The present invention provides image information, and includes an intra-coding method for coding an image in an image,
A method for predictively encoding an image with reference to another image, and encoding the image compression information using a prediction encoding method that can be decoded only by inverting the prediction direction when the display order is reversed. It provides image information.

That is, according to the present invention, when encoding image information, that is, a video source signal, into image compression information, that is, video data, intra coding that is not affected even if the prediction source pictures are rearranged for reverse reproduction. Method and
The problem that a large number of pictures have to be decoded within a display time interval of one picture is solved by an encoding method using a prediction method that enables decoding only by inverting the prediction direction.

In a playback terminal that reads and decodes video data, during reverse playback, a bidirectional prediction coded image coded by referring to the front and rear in the display order, ie, forward prediction and backward prediction in a B picture. Is inverted and decoded, so that the same decoding as during normal reproduction can be performed during reverse reproduction. Alternatively, it is possible to perform reverse playback by a decoding unit having only the normal playback function by converting the forward prediction and the backward prediction in the B picture to be inverted before inputting to the decoding unit and rearranging the order of the pictures. I do.

Further, in a data distribution system in which a server distributes stored video data to a decoding terminal via a transmission medium, the server performs conversion so that forward prediction and backward prediction in a B picture are inverted before distribution. By distributing the pictures after rearranging the order, it is possible to perform reverse reproduction that does not require a special data distribution method. The transmission medium, the receiving unit, and the decoding unit do not need to support a special data format for reverse reproduction. Since data conversion for reverse reproduction in the server can be performed without re-encoding, there is no deterioration in image quality, processing is simple, and no extra frame memory is required.

[0025]

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

First, as a first embodiment, FIG. 1 shows a reproducing terminal to which the present invention is applied. This playback terminal 120
Is for storing, decoding, and displaying image information, that is, image compression information obtained by encoding a video source signal, that is, video data.

The reproduction terminal 120 is connected to the special reproduction control unit 102
, An encoding unit 105, a recording medium 107, a reading unit 109, a data conversion unit 108, and a decoding unit 110.

The video source signal 104 input to the reproduction terminal 120 is encoded by the encoding unit 105 into the video data 10.
6 and stored in the storage medium 107. The reading unit 109 stores the video data 106 in the recording medium 107
And sends it to the data conversion unit 108. The data converter 108 converts video data for special reproduction,
Send to decoding section 110. The video data is decoded by the decoding unit 110 and displayed by a display terminal (not shown). When performing special playback such as reverse playback, the special playback control unit 10 according to the special playback designation input 101 of the user.
2 controls the reading unit 109 and the data conversion unit 108. Note that a reproduction-only terminal may not include the encoding unit 105 in some cases.

Hereinafter, IS is used as a video data encoding method.
The case where O / IEC13818-2 is used will be described as an example. The encoding device according to the present embodiment includes an intra-coded image, that is, an I-picture to be encoded only from intra-frame data, and a forward (forward) frame from the front (forward) and backward (reverse) frames in display order. It is characterized in that encoding is performed using only bidirectional predictive encoded images, that is, B pictures, which are encoded using prediction and backward (reverse) prediction. In this encoding apparatus, it is necessary to decode a plurality of pictures in order to obtain a prediction source picture at a display time interval of one picture when performing reverse playback by using an encoding configuration using only I pictures and B pictures. There is no.

In order to explain the operations of the read section 109 and the data conversion section 108 of the present embodiment, a conversion process for reverse reproduction will be described. 2A shows the video data for normal reproduction in coding order, and FIG. 2B shows the video data for normal reproduction in display order. Video data encoded by the encoding device according to the present embodiment includes only I pictures and B pictures. I and B in the figure represent picture types, and subscripts represent display order. IS
The encoding order of I-pictures in the video data of O / IEC13818-2 is such that when decoding a B-picture, the I-pictures before and after as a prediction source need to be decoded in advance.
It is rearranged and encoded in the display order of the immediately preceding I picture.

On the other hand, FIG. 2C shows converted video data in the encoding order, and FIG. 2D shows converted video data in the display order. Specifically, it shows the case of starting the reverse reproduction from immediately after the B-picture B _5. During reverse playback,
As shown in FIG. 2D, the reading unit 109 in the playback terminal 120 rearranges and reads the order of the pictures so that the display order of the decoded pictures is reversed. Since the video data encoded by the encoding apparatus according to the present embodiment is composed of only I pictures and B pictures, one picture is displayed at a time interval during which one picture is displayed, as during normal playback. When decrypted, reverse playback becomes possible. For example, when decoding a B picture B ₅ in reverse reproduction, I ₃ and I ₆ is the predicted original picture B ₅ is already decoded, the prediction based on picture by detecting the I-picture in order to obtain a plurality of I There is no need to decode pictures and P-pictures.

However, as a result of rearranging the pictures in order to reverse the reproduction direction, the prediction source picture of the B picture is reversed. For example B-picture B ₅ is as for normal playback video data is encoded using a backward prediction from forward prediction and I ₆ from I _3. However, when sorted for reverse reproduction is predicted based on the picture of the forward prediction to I ₆ instead I _3, predicted original picture backward prediction from being decoded as an I ₃ instead I _6. Therefore, the reproduction terminal 120 of the present embodiment shown in FIG.
The data conversion unit 108 in FIG. 3 exchanges forward prediction data and backward prediction data in video data to cope with the fact that the prediction source picture is reversed. That is, the forward prediction from the backward prediction and I ₆ from I ₃ for example a B-picture B ₅ that has been encoded using a backward prediction from forward prediction and I ₆ from I _3, for reverse reproduction Convert to data. Since each prediction data refers to the same prediction source picture as in normal reproduction, decoding can be performed without contradiction.

The data conversion is performed by the data conversion unit 1
At 08, this is performed using the data structure of the picture of ISO / IEC13818-2. The encoded data of the picture is shown in FIG.
A, a header (picture_header), a coding extension (picture_coding_extensio)
n) and data (picture_data). As shown in FIG. 3B, picture_encoded in the header
From coding_type, it is possible to know whether the picture is an I picture, a P picture, or a B picture. In the header, temporal_reference indicating a display order that is increased by one for each picture is encoded. temporal_reference is a GOP (GroupOf Picture
Reset to 0 every s). As shown in C of FIG. 3, f_code representing a search range of a motion vector used for decoding is encoded in picture_coding_extension. The f_code has a horizontal direction and a vertical direction for each of forward prediction and backward prediction. As shown in FIG.
ure_data starts from a slice (slice), and as shown in FIG.
ck). As shown in F of FIG. 3, since encoding using prediction is performed for each macroblock, a motion vector (motion_vector) indicating a reference position in a prediction source picture is encoded for each macroblock. . In a B picture, a prediction method can be specified for each macroblock, and the coding method is a prediction coding unit type, that is, a macroblock type (macr type).
oblock_type). The types of prediction of macroblocks of a B picture include only intra prediction and forward (forward) prediction (f
orward), backward (reverse) prediction only (backward), interpolation using both forward and backward prediction (interpolation)
Exists. If prediction is used, the motion vector is encoded. In the case of interpolation,
motion_vector (0) and motion vector moti for backward prediction
Two vectors of on_vector (1) are encoded.

At the time of reverse reproduction, the data conversion unit 108 sets the tempo encoded in the header of all the pictures in accordance with the display order changed with the reverse reproduction.
Convert oral_reference. Further, the data conversion unit 10
No. 8 performs the data conversion for the reverse reproduction in the procedure shown in FIG. 4 because the prediction source picture is affected by the rearrangement for the reverse reproduction with respect to the B picture.

In the first step S401, the data conversion unit 108 performs the B
Since the prediction source picture before and after the picture has been switched,
For f_code representing the search range of the motion vector, the front and rear are switched. That is, forward_horizontal_f_c
ode with backward_horizontal_f_code and forward_vertica
Replace l_f_code with backward_vertical_f_code respectively.

In step S402, the data conversion unit 108 determines the macroblock type (macroblock_type) encoded for each macroblock.
, The type of prediction used in the macroblock is determined. And macro block type (macrob
If the lock_type is forward / backard, the process proceeds to step S403, and if the lock_type is interpolation, the process proceeds to step S404. In the case of intra, since rearrangement for reverse playback does not affect decoding without referring to the prediction source picture, macroblock conversion is not performed.
Proceed to step S405.

In step S403, the type of macroblock prediction is forward prediction (forward) or backward prediction (bac
kward), where the order of the prediction source pictures is reversed by rearrangement for reverse reproduction. The data conversion unit 108 converts a macroblock type (macroblock_type) indicating only forward prediction into only backward prediction, and converts a macroblock type (macroblock_type) indicating only backward prediction into only forward prediction.

In step S404, a macro block (macr
oblock) prediction type is an interpolation using both forward and backward prediction. The data conversion unit 108 calculates a motion vector motion_v for forward prediction.
ector (0) and motion vector motion_vecto for backward prediction
Replace r (1).

In step S 405, the data processing unit 108 sets all macro blocks (macr
After the oblock) has been processed, this series of processing ends.
If there is any remaining, the data processing unit 108 proceeds to the next macroblock (macroblock) in step S406, and repeats from step S402.

As described above, according to the present embodiment, I
Since an encoding method using only a picture and a B picture is adopted, one picture may be decoded within the display time interval of one picture as in normal reproduction. FIG.
By inputting the video data converted by the data conversion shown in (1), the decoding unit can decode the video data for reverse playback by the same processing as during normal playback.

The playback terminal 1 according to the first embodiment
The converted video data 113 converted by the 20 data conversion unit 108 can be provided by a medium. The video data provided by this medium uses only I-pictures and B-pictures, and one picture may be decoded within the display time interval of one picture in the same manner as in normal reproduction. .

Next, as a second embodiment, a reproduction terminal to which the present invention is applied will be described. As shown in FIG. 5, the reproduction terminal 120 includes a special reproduction control unit 102, an encoding unit 10
5, a storage medium 107, a reading unit 109, and a decoding unit 110. The encoding unit 105 includes, as in the first embodiment described above, an I picture to be encoded only from intra-frame data and a B picture to be encoded using forward prediction and backward prediction from previous and subsequent frames. It is characterized in that encoding is performed only by using the following. Further, the reading unit 109 rearranges the order of the pictures so that the display order of the pictures decoded during the reverse playback becomes reverse playback, similarly to the reading unit 109 in the playback terminal 120 of the first embodiment. read out. The video data read by the reading unit 109 is input to the decoding unit 110 without being converted. The decoding unit 110 is different from the first embodiment in that the special reproduction control unit 102 controls
According to 03, the B picture is decoded for reverse reproduction. That is, the decoding unit 110 performs a conversion equivalent to the conversion processing performed by the data conversion unit 108 in the first embodiment at the same time as the decoding processing. Therefore, in the present embodiment,
There is no need to actually convert the data in the picture before decoding.

The decoding unit 110 decodes the B picture by exchanging the prediction source picture before and after and referring to it. For example, when decoding a B picture B ₅ in reverse reproduction in the example of reverse reproduction illustrated in C and D in FIG. 2, using the I ₃ instead I ₆ as a prediction source picture for forward prediction, backward using the I ₆ instead I ₃ as the prediction source picture for prediction. That is, in the present embodiment, video data rearranged for special reproduction is decoded only by exchanging a reference to a prediction source picture used for prediction, without any other special processing. It becomes possible to do.

Next, as a third embodiment, a data distribution system to which the present invention is applied is shown in FIG. The present embodiment relates to a video data encoding method and a conversion method for enabling distribution of data for reverse playback in a data distribution system in which a server distributes stored video data to a decoding terminal via a transmission medium. , Provide a delivery method.

As in the first and second embodiments, the coding unit 105 uses an I picture to be coded only from intra-frame data, and uses forward prediction and backward prediction from preceding and succeeding frames. And encoding using only the B picture to be encoded.

As in the first and second embodiments, the reading section 109 arranges the order of the pictures so that the display order of the pictures to be decoded is reversed during reverse playback. Reading is performed instead. As in the first embodiment, the data conversion unit 108 converts the B picture data so that the correct prediction source picture can be referred to in the video data rearranged by reversing the order of the prediction source picture for reverse playback. Convert. Decryption terminal 1
Since the converted video data 113 output from the data conversion unit 108 is distributed to the receiving unit 118 and the decoding unit 119, the same processing as in normal reproduction may be performed during reverse reproduction. Further, according to the data distribution method of the present embodiment, the rate of video data does not increase due to reverse reproduction, so that transmission medium 115 only needs to be able to distribute video data for normal reproduction. . In the server 100, data conversion for reverse reproduction is performed without re-encoding, so that there is no deterioration in image quality. Therefore, the processing is simpler than in the case of re-encoding, and no extra frame memory is required.

Next, as a fourth embodiment, an encoding system to which the present invention is applied will be described with reference to FIG. This embodiment uses a P picture instead of the video data encoding method in the first embodiment, the second embodiment and the third embodiment, and performs decoding and data decoding for reproduction. An encoding method that enables distribution after conversion is used.

Such an encoding method will be described with reference to FIG.
explain. FIG. 7A shows the display order in normal playback.
Video data is shown. P picture P_ThreeEncode
When the macroblock 701 using forward prediction is
Prediction source picture I during normal playback ₀Inside, motion vector 70
The decoding is performed based on the predicted position 700 indicated by 3. I
However, the video in the display order in the reverse playback shown in FIG.
Video data in the order in which they were rearranged for reverse playback.
When decoding data, the prediction source picture is I₆Change to
P_ThreeCannot be decoded correctly.
In the encoding method according to the present embodiment, the P picture P_ThreeInside
When encoding the black block 701, the motion of forward prediction
Prediction source picture I referenced by vector 703₀Medium prediction
Position 700 and the prediction source pixel at the same position during reverse playback
Cha I₆Compared with the inside predicted position 702,
If there is no predictive coding method using forward prediction
And encoding. Change to images at predicted positions 700 and 702
If there is fragmentation, macroblock 701 uses prediction.
Encode with an intra coding scheme that is not used. Sign above
Prediction by reordering for reverse playback
P picture is decoded correctly even if the original picture changes.
Is guaranteed. Especially when there is little change in the image
Is a method to encode using only I picture and B picture
It is possible to keep the bit rate low compared to the
Become.

Note that video data encoded by the encoding method of the present embodiment can be provided by a medium. The video data provided by this medium uses P pictures and enables decoding for reverse playback and delivery after data conversion.

Next, as a fifth embodiment, an encoding method to which the present invention is applied will be described with reference to FIG. In the present embodiment, instead of the video data encoding method in the first, second, and third embodiments, encoding is performed using a P picture using a skip macroblock. This is an encoding method that enables decoding for reverse playback and distribution after data conversion. Here, the skip macroblock is a macroblock that means that image data at the same position of the prediction source picture is used as decoded data as it is. As shown in FIG. 8B,
In the encoding method of the present embodiment, P pictures P ₃ and P ₆
Is encoded, the video source signals located at the same macroblock position in the I-pictures immediately before and after the current picture and all the P-pictures sandwiched between the I-pictures are compared.
When there is no change in the image, that is, when there is no change in the positions 800, 801, 802, and 803 in the input image in FIG.
The position of the same macroblock in all the P pictures sandwiched between the I pictures is encoded by a skip macroblock. If it is determined that there is a change in the picture and it cannot be coded as the same data, the position of the same macroblock in all the P pictures sandwiched between the I pictures is determined by an intra coding method that does not refer to the predicted picture. Is encoded by With the above encoding method, in the standard video data in the reverse reproduction shown in FIG. 8B, it is guaranteed that the P picture is correctly decoded even if the prediction source picture changes due to the rearrangement for the reverse reproduction. You.
In particular, when there is little change in the image, the bit rate can be suppressed to be lower than a method of encoding using only the I picture and the B picture.

Further, when the same macroblock positions 801 and 802 in all the P pictures P ₃ and P ₆ sandwiched between the consecutive I pictures I ₀ and I ₉ are coded by the skip macro block, The macroblock 803 at the same position in the I picture I _{9 of the
0} , the encoding is performed using the same quantization scale as the macroblock 800 at the same position in the P picture even if the reordering is performed for reverse reproduction and the prediction source picture is changed. Can be kept small. Further, the macroblock 803 at the same position in the immediately following I picture I _{9 is} the same as the immediately preceding I picture I _0.
By encoding the same encoded data as the macroblock 800 at the same position in the middle, even if rearrangement is performed for reverse reproduction and the prediction source picture is changed, the decoding result of the P picture is normally reproduced. Can be guaranteed to be equal to

The video data encoded by the encoding method according to the present embodiment can be provided by a medium. The video data provided by this medium is encoded using P pictures using skipped macroblocks, and enables decoding for reverse playback and delivery after data conversion. This video data is obtained by encoding the same macroblock in the immediately preceding I picture using the same quantization scale, and encoding the decoded image so that the decoded images become equal.

The present invention is not limited to the above-described embodiment, and the encoding device of the present invention may not be provided in a reproduction terminal or a server for data distribution.
The present invention is similarly effective by storing the video data encoded by the encoding method of the present invention in a storage medium of a playback terminal or a server.

The present invention is effective not only in the coding system defined in ISO / IEC13818-2, but also in all coding systems using prediction between pictures.

[0055]

According to the encoding method using inter-frame prediction in a reproduction terminal for decoding video data,
When performing reverse playback, there is a problem that a plurality of pictures must be decoded in advance in order to decode one picture, and the reading unit and the decoding unit of the playback terminal require a time interval for displaying one picture. , A large number of pictures had to be read ahead and decoded. In the present invention, by an encoding method using an intra-coding method that is not affected even if the prediction source pictures are rearranged for reverse playback, and a prediction method that enables decoding only by inverting the prediction direction, Reverse playback is enabled by the same decoding process as normal playback. Therefore, there is an effect that an unnecessary frame memory for storing a plurality of prediction source pictures is unnecessary, and a special high-speed decoding process is not required for reverse reproduction.

Further, the data conversion device of the present invention also replaces the motion vector for prediction with the prediction source picture replaced by the rearrangement for reverse playback, thereby completely adding to the decoding device for performing the normal playback process. Video data for reverse playback can be decoded without a function. There is an effect that reverse reproduction can be performed using a general video decoding device for normal reproduction.

Further, by performing a decoding method in which a prediction source picture to be referred to at the time of decoding is replaced and decoded in accordance with a prediction source picture to be replaced by rearrangement when performing reverse playback, reverse playback can be performed without data conversion. The decoding device can decode the video data rearranged for special reproduction only by exchanging the reference to the prediction source picture and without any other special processing.

In a data distribution system in which a server distributes stored video data to a decoding terminal via a transmission medium, a prediction source picture replaced by rearrangement for reverse reproduction by the encoding method and data conversion method of the present invention. Since the motion data for prediction has already been converted into video data in accordance with the above, a special data distribution method enables unnecessary reverse reproduction. There is an effect that the transmission medium, the receiving device, and the decoding device do not need to support a special data format for reverse reproduction. Since data conversion for reverse reproduction in the server can be performed without re-encoding, there is no deterioration in image quality, processing is simple, and no extra frame memory is required.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a playback terminal according to a first embodiment.

FIG. 2 is a diagram showing an example of rearrangement for reverse reproduction.

FIG. 3 is a diagram illustrating an encoded data structure of a B picture specified in ISO / IEC13818-2.

FIG. 4 is a flowchart showing B picture data conversion for reverse playback.

FIG. 5 is a block diagram illustrating a configuration of a playback terminal according to a second embodiment.

FIG. 6 is a block diagram illustrating a configuration of a data distribution system according to a third embodiment.

FIG. 7 is a diagram illustrating macroblock coding in a P picture according to the fourth embodiment.

FIG. 8 is a diagram illustrating encoding of a macroblock in a P picture according to the fifth embodiment.

FIG. 9 is a diagram showing reverse playback in a conventional playback terminal.

FIG. 10 is a diagram showing a configuration of a conventional data distribution system.

[Explanation of symbols]

100 server, 101 special reproduction designation input, 102
Special playback control unit, 103 control, 104 video source signal, 105 encoding unit, 106 video data, 107 storage medium, 108 data conversion unit, 109
Reading unit, 110 decoding device, 111 decoded video data, 112 re-encoding unit, 113 converted video data, 114 transmitting unit, 115 transmission medium, 116 distribution data, 117 decoding terminal, 118 receiving unit, 119
Decoding unit, 120 playback terminal

Continued on the front page (72) Inventor Yoichi Yagasaki 6-7-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Inside Sony Corporation (72) Inventor Takefumi Nagumo 6-35-35 Kita-Shinagawa, Shinagawa-ku, Tokyo Sony F term in reference (reference) 5C052 AA03 AC04 DD04 5C053 FA23 GB08 GB29 GB33 GB38 HA25 5C059 KK00 LA00 LC00 MA04 MA05 MA14 MC11 NN03 NN21 NN23 PP05 PP06 PP07 SS06 SS13 UA02 UA05 5J064 AA02 BA01 BC01 BD01

Claims (29)

[Claims] 1. An encoding apparatus for encoding image information, comprising: an intra-encoding scheme for encoding an image in an image; and a predictive encoding of the image with reference to another image, the display order comprising: And a coding means for coding image information into image compression information using a predictive coding method of reversing the prediction direction when the data is reversed and referring to the corresponding prediction original image. Image information encoding device. 2. The image compression information is coded by referring to an intra-coded image coded in the image by the intra-coding method and a front and a rear in a display order by the prediction coding method. 2. The image information encoding apparatus according to claim 1, wherein the image information encoding apparatus includes a bidirectional predictive encoded image. 3. The encoding unit encodes the image for each predetermined encoding unit, and encodes an encoding unit to be decoded with reference to a prediction original image when the display order is reversed in the display order. The coding is performed using a forward prediction coding method for coding with reference to an image of the image, and the coding is performed using an intra coding method for coding other coding units in the image. 2. The image information encoding device according to 1. 4. The encoding unit encodes the image for each predetermined encoding unit, and encodes the intra-coded image encoded by an intra-encoding scheme closest to the front and rear in display order; In all of the forward encoded images encoded with reference to the front in the display order between the intra-encoded images, the encoding unit encoded into the same encoded data is the same as the intra-encoded image. 2. The image information encoding apparatus according to claim 1, wherein encoding is performed. 5. The image information encoding apparatus according to claim 4, wherein said encoding means encodes the encoding units which may be encoded as the same data using an equal quantization scale. apparatus. 6. The image information encoding apparatus according to claim 4, wherein said encoding means encodes encoding units which may be encoded as the same data so that decoded images are equal. apparatus. 7. An image information conversion apparatus for converting image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image, wherein the encoded image constituting the image compression information is provided. Is arranged in the reverse order to the display order of the image compression information, and the prediction direction is also changed according to the change of the prediction source image referred to by the coded image. Image information conversion device. 8. The image compression information may be ISO / IEC11172-2 or
The image information is coded by a coding method defined in ISO / IEC13818-2, wherein the conversion unit converts the coded image display order of all coded images into the reverse order, In the display order, the forward and backward motion vector search ranges of the bidirectionally coded image coded with reference to the front and rear are interchanged, and the coding unit constituting the image compression information is set to the forward prediction. If the prediction coding unit type is changed to backward prediction, the prediction coding unit type is changed to change to forward prediction if the prediction coding unit type is backward prediction. 8. The image information conversion apparatus according to claim 7, wherein when is interpolation, the motion vectors of forward prediction and backward prediction are exchanged. 9. An image information decoding apparatus for decoding image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image, comprising the steps of: The decoding means for inputting the image compression information rearranged in the reverse order to the display order of the image compression information and for decoding by changing the prediction direction in accordance with the replacement of the prediction source image referred to by the encoded image. An image information decoding device, comprising: 10. An image information distribution apparatus for distributing image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image, comprising the steps of: A conversion means for rearranging the image compression information in a reverse order to the display order of the image compression information, and converting the prediction direction in accordance with the replacement of the prediction source image referred to by the encoded image. And a distribution unit for distributing the compressed image information. 11. The image compression information is obtained by encoding image information according to an encoding method defined in ISO / IEC11172-2 or ISO / IEC13818-2, and the conversion means includes: The display order of the coded images is converted to the reverse order, and the forward and backward motion vector search ranges of the bidirectional coded image coded with reference to the front and the rear in the display order are exchanged. For coding units that constitute information, convert the prediction coding unit type to change to backward prediction when the coding unit is forward prediction, and change to forward prediction when the prediction coding unit type is backward prediction. 11. The image information distribution apparatus according to claim 10, wherein the prediction coding unit type is converted so that the motion vector of the forward prediction and the motion vector of the backward prediction are exchanged when the prediction coding unit type is interpolation. 12. A medium for providing image information, wherein an intra-encoding method for encoding an image within an image and a method for predictively encoding an image with reference to another image, wherein the display order is reversed. A medium for providing image compression information obtained by compressing image information using a prediction encoding method of decoding by referring to a corresponding prediction original image when a prediction direction is reversed. 13. The image compression information is encoded by referring to an intra-encoded image encoded in an image by the intra-encoding method and a front and a rear in a display order by the prediction encoding method. 13. The medium according to claim 12, comprising a bidirectional predictive encoded image. 14. The image is coded for each predetermined coding unit, and a coding unit to be decoded by referring to a prediction original image when the display order is reversed is referred to by referring to another image ahead in the display order. Encoding using a forward prediction encoding scheme to encode,
2. The coding method according to claim 1, wherein the coding is performed using an intra coding method for coding other coding units in the image.
3. The medium according to 3. 15. An intra-encoded image encoded by the above-described image in a predetermined encoding unit, and encoded by an intra-encoding method that is closest to the front and the rear in the display order, and between these intra-encoded images. In all the forward coded images coded with reference to the front in the display order, the coding unit coded to the same coded data is coded as being the same as the intra-coded image. 14. The medium according to claim 13, wherein 16. The medium according to claim 15, wherein the coding units that may be coded as the same data are coded using an equal quantization scale. 17. The medium according to claim 15, wherein coding units that may be coded as the same data are coded so that decoded images are equal. 18. An encoding method for encoding image information, comprising: an intra-encoding scheme for encoding an image in an image; and a predictive encoding of the image with reference to another image, wherein the display order is The image information is encoded into image compression information using a prediction encoding method that reverses the prediction direction when the image is reversed and refers to the corresponding prediction original image and decodes the image information. Method. 19. The image compression information is encoded by referring to an intra-encoded image encoded in the image by the intra-encoding scheme and a front and a rear in display order by the prediction encoding scheme. 19. The image information encoding method according to claim 18, comprising a bidirectional predictive encoded image. 20. Encoding the image for each predetermined encoding unit, and the encoding unit that can be decoded even when the prediction source image to be referred to when the display order is reversed is replaced by another image ahead in the display order. 19. The image information according to claim 18, wherein the image information is encoded using a forward prediction encoding method for encoding the image information, and the other encoding units use an intra encoding method encoded in the image. Encoding method. 21. An intra-coded image obtained by encoding the image for each predetermined coding unit, and encoding the intra-coded image closest to the front and the rear in the display order, and between these intra-coded images In all the forward coded images coded with reference to the front in the display order, the coding unit that may be coded to the same coded data is coded as being the same as the intra coded image. 19. The image information conversion method according to claim 18, wherein: 22. The image information coding method according to claim 21, wherein the coding units that may be coded as the same data are coded using the same quantization scale. 23. The image information encoding method according to claim 21, wherein the encoding units which may be encoded as the same data are encoded so that decoded images are equal. 24. An image information conversion method for converting image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image, comprising the steps of: Is arranged in the reverse order to the display order of the image compression information, and the prediction direction is also changed according to the change of the prediction source image referred to by the coded image. Method. 25. The image compression information is obtained by encoding image information according to an encoding method specified in ISO / IEC11172-2 or ISO / IEC13818-2, and displays encoded images of all encoded images. The order is converted to the reverse order, and the front and rear motion vector search ranges of the bidirectionally encoded image encoded with reference to the front and rear in the display order are interchanged.
For the coding unit constituting the image compression information, the prediction coding unit type is converted so that the prediction unit is changed to backward prediction when the coding unit is forward prediction, and forward when the prediction coding unit type is backward prediction. 25. The image information conversion method according to claim 24, wherein the prediction coding unit type is converted so as to change to prediction, and when the prediction coding unit type is interpolation, the motion vectors of forward prediction and backward prediction are exchanged. . 26. An image information decoding method for decoding image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image, comprising the steps of: The image compression information in which the image compression information is rearranged in the reverse order to the display order of the image compression information is input, and the decoding is performed by changing the prediction direction in accordance with the replacement of the prediction source image referred to by the encoded image. Image information decoding method. 27. The image information decoding method according to claim 26, wherein, in accordance with said rearrangement, decoding is performed by exchanging a prediction source image referred to by said encoded image. 28. An image information distribution method for distributing image compression information obtained by encoding image information using a predictive encoding method for predictive encoding with reference to another image, comprising the steps of: Are converted in the reverse order to the display order of the image compression information, and the prediction direction is also changed according to the change of the prediction source image referred to by the coded image, and the image converted by the conversion unit is converted. A method for distributing image information, comprising distributing compressed information. 29. The image compression information is obtained by encoding image information according to an encoding method defined in ISO / IEC11172-2 or ISO / IEC13818-2, and displays encoded images of all the encoded images. The order is converted to the reverse order, and the front and rear motion vector search ranges of the bidirectionally encoded image encoded with reference to the front and rear in the display order are interchanged.
For the coding unit constituting the image compression information, the prediction coding unit type is converted so that the prediction unit is changed to backward prediction when the coding unit is forward prediction, and forward when the prediction coding unit type is backward prediction. 29. The image information distribution method according to claim 28, wherein the prediction coding unit type is converted so as to change to prediction, and when the prediction coding unit type is interpolation, the motion vectors of forward prediction and backward prediction are exchanged. .