JP3102541B2 - Skip search method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a request-type video / audio information providing system center or the like, which stores an MP
The present invention relates to a video / audio information storage / read method for storing and reading digitally-compressed video / audio data by an EG encoding method or the like, and particularly to a fast-forward reproduction method capable of outputting audio.

[0002]

2. Description of the Related Art Conventionally, in a request type video / audio information providing system, a center is connected to a large number of terminals, and video / audio information requested by the terminal is read from a storage device of the center and transmitted to the terminal. Was. Conventionally, video coding has been performed on a frame basis. However, inter-frame prediction coding for improving the compression rate cannot realize functions such as fast forward and reverse retransmission, so that an intra-frame coded screen is inserted. However, a plurality of frames are collected to form a group of pictures (hereinafter, referred to as a GOP). In order to realize fast-forward, there are (1) a skip search method for skipping and playing back a video GOP at regular intervals, and (2) a fast-forward method for selecting and playing back only a frame that has been subjected to intra-frame coded compression.

[0003]

In the above-described conventional skip search method, in the method of (1), in which a GOP is skipped at a constant interval and reproduced, a video reproduction portion to be normally reproduced becomes longer, so that a sense of high speed is lost. Conversely, when the number of consecutive GOPs is small, the portion that is substantially used for normal reproduction becomes short, and the meaning of the sound becomes unclear. In the method of (2), in which only the intra-frame coded screen is selected for fast-forward playback, since the frames are played back intermittently, a short sound corresponding to the playback frame is output stepwise, and the meaning of the sound becomes unclear. There were defects.

[0004] It is an object of the present invention to provide a video skip search method with audio that enables a video having a sense of high speed and a meaningful audio to be reproduced together.

[0005]

According to the skip search method of the present invention, when reproducing a video and audio file divided into predetermined units in synchronization with a continuous video at an average speed of n times, the skip search method according to the present invention is applied. k = m / n for each group with m times as one group
In the skip search method of selecting video of unit length and selecting and combining and playing back audio of unit length k or less for each group, the number of unit lengths selected in the group for the audio file is k. The processing of reproducing the sound is performed by combining the unit length of kp silent or noise and the p unit length of the audio file, which is p, which is a smaller numerical value.

Further, a process of selecting video files in each group so that the interval between selected unit lengths does not become constant, and a process of selecting video files in each group between unit lengths selected for video files. The present invention also includes a process of selecting the interval to gradually decrease after the interval gradually increases, and a process of alternately combining sections of the unit length of the silent or noise image and the unit length of the audio file.

[0007] Also, a unit length of p consecutive audios smaller than k is selected from m unit lengths for each group, and a unit length of the k video and a unit length of the p audios are selected. A process of combining and reproducing kp silent unit lengths and reproducing them is also a preferred embodiment of the present invention.

[0008] The predetermined unit length may be a group of picture unit.

[0009]

[Action] Digital video and audio files can be transferred to multiple GOs.
The GOP is divided into P, and the GOP is further composed of a plurality of h frames (an integer satisfying h ≧ 2), and video and audio are stored in synchronization with each frame, and m GOPs are divided into 1 frames. A group is selected, and k video reproduction GOPs are selected for each group, and the audio blocks of GPOs in which the identifiers of the selected k GOPs are odd are replaced with no-sound data or noise, or m Since p consecutive GOPs are selected from among the GOPs for audio reproduction, and the audio blocks are combined with the video blocks and reproduced, the video reproduction including the audio output that makes sense is possible.

[0010]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing a configuration relationship between a GOP and a frame of a continuous image according to the present invention, and FIG.
FIG. 2B shows the OP reading selection order, and FIG.
FIG. 3 is a diagram showing a combination of video and audio of a GOP selected in (a), and FIG. 3 is a flowchart of a first embodiment of a skip search method according to the present invention.

The digital moving image information (video and audio information) file of the continuous video in this embodiment has GOPm files (m in this embodiment) of 15 video frame configurations shown in FIG.
= 20) as a group and store an arbitrary number of groups in a physically continuous area of the storage device. In the figure, a GOP is a GOP identifier G and a serial number G assigned to the GOP, such as G001.
OP number (3 digits), and the frame is also f00
A frame identifier f and a 3-digit serial number such as 1, f002 are displayed. Further, in the present embodiment, the number of selections k for reproducing and displaying a group of GOPs is k = 4, and the group configuration is such that m = 20 GOPs of consecutive GOP numbers are divided. Also, the audio portion of the odd-numbered GOP in the selection order is replaced with non-audio data or noise so that audio and non-audio data are alternately arranged or audio and noise are alternately arranged. Hereinafter, on average, 5 times speed (n =
The variable-speed video skip search method (m / k = 5) will be described.

The first embodiment is a mode in which the skip width gradually increases.

The moving picture information file of the present embodiment is a bit string in which the moving picture information is encoded at a bit rate of 6 bits / second and has moving picture information of 30 frames / second. One GOP stores 15 frames, and GOP4
Assuming that reading is performed in units of one unit, the display time of one frame is 1/30 second, so that for 4 GOPs, that is, 60 frames, 60/30 seconds = 2 seconds. Therefore, 4G
The OP reading time (Tr) must be shorter than the display time (2 seconds). Assuming that the storage device is a magnetic disk device having an access time of 50 ms and a reading speed of 20 Mbit / s, the time required to read and process four GOPs (corresponding to 2 seconds) is Tr = 50 ms + (6 Mbit / s). 20 Mbit / s) ×
2 = 0.65 seconds, which sufficiently satisfies the condition of 2 seconds or less. With the 6-Mbit / sec moving image information (including audio information) of this embodiment, it is possible to read / reproduce and display up to three multiplexes (2 ≒ 0.65 ≒ 3).

A specific example of this embodiment will be described below.

This is an embodiment of a mode in which the skip width a _j gradually increases as a skip mode in one group. Skip G
Assuming that the increment (d _{j + 1} ) of the number of OPs is constant and c, _{aj + 1} = _aj + _{dj + 1} = _aj + c (11)

[0017]

(Equation 1) a _j ≧ 1 (13) From Expressions 11 and 12

[0018]

(Equation 2) ∴m = (1 + a ₁ + c × (k−1) ÷ 2) × k (14) Here, at an average 5 × speed where m = 20 and k = 4, Expression (14) is as follows: 20 = 4 + 4a ₁ + 6c 2a ₁ + 3c = 8 (15) FIG. 2A shows that a ₁ = 1, c = 2, m = 20,
FIG. 9 is a GOP reading diagram in the case of an average 5 × speed mode when k = 4. FIG. 2B is a video / audio combination diagram in the average 5 × speed mode. In FIG. 2A, the number V of the video data storage GOP to be read i-th
Assuming that [] is a Gaussian symbol, the value of (i) is V (i) = (mk) [(i−1) ｉk] + i + (i−
1 − [(i−1) {k] × k) ² = 16 [(i−1)}
4] + i + (i−1 − [(i−1) ÷ 4] × 4) ^{2 Further} , assuming that a combined block of audio and video reproduced and output at the time of a skip search is S (i), S (i) becomes When i is an even number, the audio block A (i) is used, and when i is an odd number, silent data (stored in the dedicated area B of the storage device in advance) is used. Therefore, S (i) = V (i) + B (i is an odd number) S (i) = V (i) + A (i) (i is an even number)

FIG. 3 is a flowchart for reading and reproducing a GOP according to the first embodiment of the present invention. In the figure, Sn indicates a step number.

1) First, a GOP pointer i and a fast-forward GOP number counter j in a file are initialized to 1 (i
= J = 1) (step 1).

2) It is determined whether the instruction of the reproduction type is fast forward reproduction or normal reproduction (step 2). 3) At the time of normal reproduction, the GOP of the pointer i is read (step 3).

4) GOP of the read GOP pointer
Is reproduced (step 4).

5) Next, the GOP pointer is incremented (i = i + 1) (step 5).

6) It is checked whether or not the reproduction process has reached the GOP pointer designated in advance. If the reproduction process has not reached the GOP pointer, the process goes to step 3, and if the end is confirmed, the process stops (step 6).

7) On the other hand, if fast-forward playback (high-speed playback) is determined in step 2, the value of the GOP pointer i (i = j = I0) at which fast-forward playback is started is extracted (step 7).

8) The address of the read GOP for fast-forward playback is calculated (step 8). Specifically, V (j)
= V (j) + I0.

9) The GOP of V (j) is read (step 9). 10) Determine whether j is odd or even (step 1)
0). 11) If j is an odd number, the video block of the GOP of V (j) and the audio block of the GOP of A (j) are combined on the buffer (step 11). That is, S (j) = V (j) + A (j) = V (j) + B where B is a storage block of silence data. 12) If j is an even number in step 10, the video block and the audio block are combined on the buffer (step 12). That is, S (j) = V (j) + A (j) = V (j) 13) S (j) is reproduced and displayed as fast-forward reproduction data (step 13). 14) The output pointer j for fast-forward playback is incremented (j = j + 1) (step 14). 15) It is determined whether or not the reproduction process is to be continued based on whether or not the fast-forward reproduction has reached a preset group. If the reproduction process is to be continued, the process proceeds to step 9 (step 15). 3 to return to normal reproduction (step 16).

FIG. 4 is a diagram showing an average 5 × speed video / audio output when normal reproduction is performed up to the GOP of G100 and the fast forward reproduction shown in FIG. 3 is performed from G101, and FIG. .

Next, a second embodiment will be described.

In the second embodiment, the skip width gradually increases and then gradually decreases. Here, the increment (d _{j + 1} ) of the number of skip GOPs is d (constant) when increasing, and −d (constant) when reaching the peak and gradually decreasing, and a _{j + 1} = a _j + _{dj + 1} (21)

[0031]

(Equation 3) a _j ≧ 1 (23) From the above equations 21 and 22

[0032]

(Equation 4) Ｍm = (1 + a ₁ + d × (k−1) ÷ 2) × k (24) Here, in the example of the case of an average 5 × speed where m = 20 and k = 4, the equation 24 becomes: 20 = 4 + 4a ₁ + 6d∴2a ₁ + 3d = 8 (25) FIG. 6A shows a ₁ = 1, d = 2, m = 20, k
FIG. 6B is a GOP reading diagram in the average 5 × speed mode in the case of = 4, and FIG. In FIG. 6A, if the number of the GOP having the i-th video block to be read is V (i), || is an absolute value symbol, and [] is a Gaussian symbol, V (i) = e ² + (| 5-2e | -3) / 2 where e = i−4 × [(i−1) ÷ 4].

S (i) is a combined block of audio and video at the time of fast-forward playback. For S (i), audio data A (i) is used when i is an even number, and when i is an odd number, The silent data stored in the dedicated area B of the storage device is used. Thus, if U is a symbol of a theoretical sum, S (i) = V (i) ∪A (i) (i is an even number) S (i) = V (i) ∪B (i is an odd number) FIG. 7 is an output diagram of an average 5 × speed video and audio when performing normal playback up to the GOP of G100 and performing fast forward playback in a mode in which the skip width gradually increases and then decreases from G101, and FIG. It is a speed change figure.

Next, a third embodiment will be described.

In this embodiment, if the number of continuous GOPs is m = 20, the number of reproduced display GOPs per group is k = 4, and the number of continuous audio GOPs per group is p = 3, the i-th The number V (i) of the GOP having the video block to be read is as follows. Here, assuming that # is the symbol indicating the following, V (i) = # (m−k) [(i−1) ÷ k] + i +
[(I−1) ÷ k] × k) ² FIG. 9A is a GOP reading diagram in the average 5 × speed mode when a ₁ = 1, m = 20, k = 4, and p = 3.
By substituting this numerical value, V (i) = # 16 [(i-1)
{4] +1 (i−1) ÷ 4] × 4) ² Also,
If the GOP number having the i-th audio block to be read is A (i), when i is a multiple of 4, A (i)
= Silent data stored at the position of #B (where i = 4n). When i is not a multiple of 4, A (i) = # m × [(i−1) ÷ k] + i = 20 ×
It is stored at the position of [(i−1) ÷ 4] + i (where i ≠ 4n). V (1),
And A (i) are as follows: V (1) = # 01, A (1) = # 01 V (2) = # 03, A (2) = # 02 V (3) = # 07, A (3) = # 03 V (4) = # 13, A (4) = # B

Here, V (1) = A (1) = # 01, V
Since (2) = A (3) = # 03 overlaps, V
(1) The GOP of the GOP number corresponding to the numerical values of A (2), V (3), V (4), and A (4) is read.

Let S (i) be the combined block of video and audio for skip search, and let 論理 be the symbol of the logical sum: p ≧ j ≧ 1 S (i) = V (i) ∪ A (i) k ≧ j ≧ p + 1 S (i) = V (i) ∪B Taking the first cycle as an example, S (1) = V (1) ∪A (1) = # 01∪ # 01 = # 01 S (2) = V (2) ∪A (2) = # 03∪ # 02 S (3) = V (3) ∪A (3) = # 07∪ # 03 S (4) = V (4) ∪A (4) = # 13∪ # B FIG. 9 (b) is a video / audio combination diagram at an average 5 × speed.
Is shown.

[0038]

As described above, according to the present invention, k
GOPs for video fast-forward playback are selected, and G
Since the audio block of the GOP in which the identifier of the OP is an odd number is silence or noise, or one of the selected GOPs is combined with the audio blocks of the p consecutive GOPs and played back with the video block, the following is performed. effective.

1. The skip search of the video to which the continuous sound is added makes it easy to understand the meaning of the video scene.

2. Since the skip width or the double speed of the GOP is dynamically changed with respect to the search in GOP units, a sense of fast-forward speed can be obtained.

3. Since silence data or noise is inserted in the connection between the voices in GOP units,
Sound sounds smooth.

The above effects are effective for a picture search of a video program having a GOP structure by an inter-frame coding system such as the MPEG system.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a GOP used in the present invention.

FIG. 2A is a diagram showing GOP reading in a first embodiment of a skip search method according to the present invention, and FIG. 2B is a combined video / audio diagram of the read GOP.

FIG. 3 is a flowchart of a skip search method according to a first embodiment of the present invention;

FIG. 4 is a video / audio output diagram at an average 5 × speed of the first embodiment.

FIG. 5 is a diagram illustrating a GOP reading state according to a double speed change of an average of five times of an image in the first embodiment.

FIG. 6 (a) shows a GO at an average 5 × speed of the third embodiment.
FIG. 3B is a P-read diagram, and FIG.

FIG. 7 is a diagram showing video and audio output at an average 5 × speed in the third embodiment.

FIG. 8 is a diagram illustrating a GOP read state for an average 5 × speed according to the third embodiment.

FIG. 9 (a) is a graph showing G for the average 5 × speed of the third embodiment.
The OP reading diagram, (b) is the video / audio combination diagram.

Claims (6)

(57) [Claims] 1. When reproducing video and audio files divided by a predetermined unit length in synchronization with a continuous video at an average speed of n times, k times a group of m times the unit length.
= M / n unit length videos are selected, and k or less unit length audios are selected and combined and played back for each group. Number is k
A skip search method characterized in that a sound is reproduced by combining k-p unit lengths of silence or noise and p unit lengths of an audio file, where p is a smaller number. 2. The skip search method according to claim 1, wherein the video files in each group are selected such that the intervals between the selected unit lengths do not become constant. 3. The skip search method according to claim 1, wherein the interval between unit lengths selected for the video file in each group is selected so as to gradually increase and then gradually decrease. 4. The skip search method according to claim 1, wherein a unit length of the unit length of the silent or noise video and a unit length of the audio file are alternately combined. 5. The unit length of p continuous audios smaller than k is selected from the m unit lengths for each group, and the unit length of k video and the unit of the p audios are selected. 2. A combination of a length and kp silent or noise unit lengths for reproduction.
Skip search method described. 6. The skip search method according to claim 1, wherein the predetermined unit length is a group of picture unit.