JP2907761B2 - Video encoding information creation device for real-time fast-forward playback - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a moving picture coded information reproducing system which supports not only normal reproduction but also forward and backward fast forward reproduction (visual search).
A video-on-demand system for interactively reproducing video encoded information between a video server and a terminal through a communication line, which relates to a device for creating video encoded information for fast-forward playback that is stored in a storage device such as a video server in advance. It is used for inputting moving image information to a video server in a (VOD) system and for inputting moving image information to a stand-alone type video disk device.

[0002]

2. Description of the Related Art In a video-on-demand service for providing moving images, a video server storing video coding information and a set-top device for reproducing the coding information are connected by a communication path, and a home VTR device is used. As a method for realizing fast-forward playback (visual search) such as that realized by, video encoding information for normal-speed playback and video encoding information for fast-forward playback (generally, And N (N is a natural number) frames of moving pictures extracted from the moving pictures for normal reproduction, which are encoded every N frames, and a normal reproduction request and a fast-forward reproduction request are issued from the set-top device. A method has been proposed in which the moving picture coding information to be reproduced is switched to the moving picture coding information for normal speed reproduction and the moving picture coding information for fast forward reproduction every time. See Japanese Patent Application Laid-Open No. 6-133262).

In order to realize this method, a moving picture coding method for normal reproduction is encoded by a moving picture coding method using both intra-frame coding and inter-frame coding in consideration of compression efficiency, and fast-forward reproduction is performed. As the moving picture coding method, since it is not known at which point the set-top device requests fast-forward playback, intra-frame coding that allows random access in frame units is used.

Conventionally, a device as shown in FIG. 4 (Japanese Patent Application Laid-Open No. Hei 7 (1995) -19710) has been proposed as a device for creating this moving image encoded information for fast forward reproduction.
No. 69036). The apparatus first encodes an original moving picture frame 40 by a first encoder 41 that uses both intra-frame coding and inter-frame coding to create moving picture coding information 42 for normal speed reproduction. Next, the decoder 43 decodes the moving image frames for every N frames from the created moving image coding information for normal speed reproduction 42, and further outputs the decoded moving image frame information 44 for each N frame in the frame. The encoding is performed again by the second encoder 45 including only the encoding so that the bit rate becomes a predetermined fast-forward playback bit rate, and the fast-forward playback moving image encoded information 46 is generated. At this time, the fast-forward playback bit rate is usually set to be equal to the bit rate during normal playback.

[0005]

In the conventional method, first, after the first encoding is performed, the output is decoded every N frames, and after the decoding, the output is Further, the second encoding is performed. Since these processes require a sequential operation, it was impossible in principle to parallelize the processes.

As a result, the amount of time required for encoding (decoding delay) and the time required for decoding (decoding delay) with respect to the generation of coded information for normal reproduction is a moving image for fast-forward reproduction. The generation of the encoded information will be delayed. If both the encoding delay and the decoding delay for one time are 3 seconds, the generation of the encoding information for fast-forward reproduction is delayed by 6 seconds with respect to the generation of the encoding information for normal reproduction.

SUMMARY OF THE INVENTION An object of the present invention is to provide an apparatus for creating moving picture encoded information for fast-forward reproduction without delay in principle for generating moving picture encoded information for normal speed reproduction.

[0008]

SUMMARY OF THE INVENTION The present invention is directed to an apparatus for creating moving image encoded information for N-times fast forward reproduction of moving image encoded information for normal speed reproduction, wherein each moving image frame constituting a moving image is provided. Is encoded by a moving picture coding method using both intra-frame coding and inter-frame coding so as to satisfy a predetermined normal reproduction bit rate, thereby generating moving picture coding information for normal speed reproduction. From the moving image frames constituting the moving image, and fetches only each moving image frame for every N frames, and encodes them using an intra-frame encoding method so as to satisfy a predetermined fast-forward reproduction bit rate. And a means for synchronizing the start and end of encoding between the two encoders.

The second encoder extracts only N video frames from each of the video frames constituting the video by counting the number of frames inside the second encoder. It shall be the structure for generating a fast-forward reproduction moving image coded information by performing intra-frame coding on them.

[0010] Alternatively, the second encoder extracts only N video frames from N video frames constituting the video using an interval timer inside the second encoder. it configured to generate a fast-forward reproduction moving image coded information by performing intra-frame coding on.

Alternatively, the second encoder once encodes all the moving image frames by intra-frame encoding.
Refers to the header information described for each frame coding information, it configured to generate a moving picture coding information for fast-forward reproduction by taking out only the encoded information for each N frames.

The operation of the present invention is as follows. Each moving image frame constituting the moving image is encoded by a first encoder by a moving image encoding method using both intra-frame encoding and inter-frame encoding so as to satisfy a predetermined normal reproduction bit rate. Generates moving picture coding information for normal speed reproduction, extracts only each moving picture frame for every N frames from each moving picture frame constituting the same moving picture, and uses the second encoder to perform intra-frame coding. The encoding is performed so as to satisfy a predetermined fast-forward reproduction bit rate by using the encoding method, thereby generating moving image encoded information for fast-forward reproduction.
These two encoders are connected by means for synchronizing, and the start and end of encoding are synchronized.

Therefore, it is possible to temporally associate the generated normal-speed reproduction moving picture coding information with the fast-forward reproduction moving picture coding information, and to perform the normal-speed reproduction moving picture coding information. It is possible to create moving image encoding information for N-times fast-forward reproduction.

At this time, by counting the number of frames inside the second encoder or using an interval timer inside the second encoder, even if each moving image frame for every N frames is taken out, Good. Further, once all the moving image frames are encoded by intra-frame encoding, the second encoder refers to the header information described for each frame encoding information, so that only the encoding information for every N frames is obtained. It is also possible to take out.

In any case, the operation in the first encoder and the processing in the second encoder are independent, and the object of the present invention is to convert the moving image encoding information for normal speed reproduction. It is possible to provide an apparatus that creates moving image encoding information for fast-forward reproduction without a theoretical delay for generation.

[0016]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a block diagram of an apparatus according to an embodiment of the present invention. In the figure, reference numeral 1 denotes a moving image frame constituting a moving image, and 2 denotes a first encoder for performing encoding by a moving image encoding method using inter-frame encoding so as to satisfy a predetermined normal reproduction bit rate. ,
Reference numeral 3 denotes moving image encoded information for normal speed reproduction generated by the first encoder 2, and numeral 4 extracts only each N moving image frame from each moving image frame constituting the moving image frame 1, and The second encoder 5 performs encoding so as to satisfy a predetermined fast-forward reproduction bit rate by using the inner encoding method, and fast-forward reproduction moving image encoding information generated by the second encoder 4 Reference numeral 6 denotes a signal line for transmitting a synchronization signal for starting and ending encoding to the first encoder 2 and the second encoder 4, and 7 denotes a first encoder and a second encoder. And a synchronization control unit that controls the synchronization of the start and end of encoding with the encoder 4.

Further, reference numeral 10 denotes a frame extracting means by a counter for extracting a moving image frame every N frames from the moving image frame 1 by counting the number of frames in the second encoder 4, and 11 denotes encoding by an intra-frame encoding method. Means 12, frame extracting means by an interval timer for extracting moving image frames from the moving image frame 1 every N frames in the second encoder 4 by an interval timer; 13, encoding means by intra-frame encoding; Encoding means 15 for encoding the entire moving image frame 1 by intra-frame encoding, and encoding information extracting means 15 for extracting only the encoding information for every N frames by referring to the header information described for each frame encoding information Represent.

The second encoder 4 shown in FIG. 1A uses, for example, a frame extracting means 10 and an encoding means 11 using a counter shown in FIG. 1B, or an interval timer shown in FIG. It comprises a frame extracting means 12 and an encoding means 13 or an encoding means 14 and an encoding information extracting means 15 shown in FIG. 1 (D), and fast-forward playback moving image encoding information 5 which is encoding information for every N frames. Is generated by the first encoder 2 using the moving image encoded information 3 for normal speed reproduction.
Is performed at the same time as the generation of

FIG. 2 is a timing chart showing the operation of this block configuration. Reference numeral 20 denotes a frame presence signal in a moving image frame 1 constituting a moving image;
1 is a signal during execution of encoding in the first encoder 2, 22
Represents a signal during execution of encoding in the second encoder 4, 23 represents an encoding start signal instructing the start of encoding, and 24 represents an encoding end signal instructing the end of encoding.

The frame presence signal 20 is represented by f1, f2,
f3,..., f100 are signals that go high each time a frame exists. On the other hand, the encoding-in-progress signals 21 and 22 are high-level signals when the frame is being encoded. For example, the encoding-in-progress signals 21 and 22 both attain a high level at the time of f3. This means that both the first encoder 2 and the second encoder 4 have executed the encoding of the third moving image frame f3.

Here, it is assumed that the synchronization control unit 7 has transmitted an encoding start signal 23 to the signal line 6 at the start of the moving image frame at f3 in response to an instruction to start encoding from outside. The first encoder 2 starts encoding immediately from the third moving image frame f3, and performs encoding in order of f3, f4, f5. At the same time, the second encoder 4 that has received the encoding start signal 23 via the signal line 6 immediately starts encoding from the third moving image frame f3. However, after encoding one frame, the second encoder 4 does not execute encoding for a time interval 25 of N-1 frames. Therefore, one frame is encoded every N frames.

FIG. 2 shows an example in which N is set to 3, and the second encoder 4 does not perform encoding for two frames of f4 and f5, but at a rate of one frame for every three frames. Encoding has been performed. At this time, as a method of setting the timing of the time interval 25 at which the encoding is not performed,
For example, using the configuration shown in FIG.
The method can be realized by a method of counting the number of frames of the moving image frame 1 input inside the. Further, since the intervals between the frames are constant, there is also a method of using an interval timer for measuring a fixed time interval inside the second encoder 4 as shown in FIG. 1C.

Finally, f99 of the moving image frame is externally input.
It is assumed that the end of encoding is instructed at the end of. The first encoder 2 ends the encoding at the 99th video frame f99 in response to the encoding end signal 24 from the synchronization control unit 7 via the signal line 6. At the same time, the encoding end signal 24 is transmitted to the second encoder 4 via the signal line 6, and the 99th moving image is also sent to the second encoder 4 which has received the encoding end signal 24. The encoding ends at frame f99.

FIG. 3 shows an embodiment of the present invention, in which the moving image encoded information 30 for normal speed reproduction generated by the first encoder 2 and the moving image for fast forward reproduction generated by the second encoder 4. 5 shows image encoding information 31.

I3, I6, I9,... Included in the moving picture coded information 30 for normal speed reproduction are the original frames f3, f
6, f9,... Are frame coding information generated by intra-frame coding of P4, P5, P7,.
Are frame coding information generated by performing inter-frame coding on the original frames f4, f5, f7,. On the other hand, I3 ′, I6 ′, I9 ′,... Included in the video coding information 31 for fast-forward playback are the original frames f3,
.. are frame encoding information generated by intra-frame encoding of f6, f9,.

FIG. 3 shows an example in which the normal reproduction bit rate and the fast-forward reproduction bit rate are made equal to each other.
The amount of frame encoded information for the frame matches the amount of frame encoded information for three frames I3 ', I6', and I9 'of the moving image encoded information 31 for fast-forward playback.

The moving picture coded information 30 for normal speed reproduction includes
Since intra-frame coding and inter-frame coding are used together, random access can be performed only in units of frames in which intra-frame coding is performed, such as I3, I6, and I9. There is a feature that the image quality is better than that of the coded information obtained by performing the intra-frame coding.

On the other hand, the video coding information 31 for fast-forward playback
Since all of them use intra-frame encoding, the overall image quality is inferior, but there is a feature that random access using an arbitrary frame as a reproduction start frame is possible. Also, since the reproduction bit rates of the moving image encoded information 30 for normal speed reproduction and the moving image encoded information 31 for fast-forward reproduction are the same, even if the encoding information to be reproduced is switched on the way, the communication path is not changed. It is characterized in that the load applied to an external device such as a computer or a set-top device does not change. In addition, in the two pieces of moving picture coding information 30 and 31, a header section is provided in the coding information, and the management information described in the header section is included in FIG.
It is possible to store the association information of the frame encoding information as shown in FIG.

Utilizing these properties, each time a normal reproduction request or a fast-forward reproduction request is issued from an external device such as a set-top device, the moving image coding information to be reproduced is respectively set to the moving image coding for normal speed reproduction. By switching to the information 30 and the fast-forward playback moving picture encoded information 31, it becomes possible to switch between normal playback and fast-forward playback.

For example, when the fast-forward command is issued from an external device while the frame coded information I3 of the normal-speed playback coded video information 30 is being played back, the correspondence of the fast-forward playback coded video information 31 is provided. The reproduction point is moved to the frame encoding information I3 'to be processed, and then I3', I6 ', I9',.
By reproducing the moving picture encoded information 31 for fast-forward playback in this order, it is possible to show fast-forward playback to an external device. Further, when an external device instructs normal reproduction during reproduction of the frame coded information I6 'of the video coded information 31 for fast-forward reproduction, the corresponding frame of the video coded information 30 for normal speed reproduction is output. Encoding information I
Move the playback point to 6, then I6, P7, P8, ...
By reproducing the moving image encoded information 30 for normal speed reproduction in this order, normal reproduction can be shown to an external device.

As described above, by using the two pieces of encoded information of the moving picture encoded information 30 for normal speed reproduction and the moving picture encoded information 31 for fast-forward reproduction created by the present invention, the reproduction bit can be transmitted to an external device. Fast forward playback without changing the rate /
It is possible to provide a mode switching function for normal reproduction.

In this embodiment, the case where the number of the second encoder 4 for generating the coded information for fast-forward reproduction is one is shown, but the second coder 4 having a different frame interval N for performing the encoding is used. By preparing a plurality of moving picture coding information, a plurality of moving picture coding information for fast-forward reproduction having different double speed values can be simultaneously prepared. Further, in the present embodiment, the method of setting the timing of the time interval 25 in which the encoding is not performed in the second encoder 4 has been described.
Once all the moving image frames are coded by intra-frame coding, such as I3 ', I4', I5 ', ..., the header information in the coded information in which the number of each frame coded information is described is referred to. By doing, I3 ', I6', I
A method of extracting only the frame coding information for every three frames, such as 9 ',..., Can be similarly realized.

[0033]

As described above, according to the present invention, the operation in the first encoder and the processing in the second encoder are independent, and the normal speed reproduction which is the object of the present invention is performed. It is possible to provide an apparatus for generating fast-forward playback moving image encoded information without delay in principle for generation of moving image encoded information.

[Brief description of the drawings]

FIG. 1 is a diagram showing a block configuration of an apparatus according to an embodiment of the present invention.

FIG. 2 shows a timing chart of an operation in the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of moving image encoded information for normal speed reproduction and moving image encoded information for fast forward reproduction generated in the embodiment of the present invention.

FIG. 4 is a diagram showing a block configuration of a conventional fast-forward playback moving picture encoded information creating apparatus.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 moving image frame 2 first encoder 3 moving image encoded information for normal speed reproduction 4 second encoder 5 moving image encoded information for fast forward reproduction 6 signal line 7 synchronization control unit 10 frame extraction means by counter DESCRIPTION OF SYMBOLS 11 Encoding means 12 Frame extraction means by an interval timer 13 Encoding means 14 Encoding means 15 Encoding information extraction means 20 Presence signal of frame 21 Encoding execution signal in first encoder 22 Second encoder During encoding 23 Encoding start signal 24 Encoding end signal 25 Time interval during which no encoding is performed 30 Moving image encoded information for normal speed reproduction 31 Moving image encoded information for fast forward reproduction

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Akira Uemori Nippon Telegraph and Telephone Corporation, 1-6-1, Uchisaiwaicho, Chiyoda-ku, Tokyo (56) References JP-A-6-339113 (JP, A) Hei 6-133262 (JP, A) JP-A-8-265691 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) H04N 5/91-5/956 H04N 7/24-7 / 68

Claims (3)

(57) [Claims] 1. An apparatus for creating moving image encoded information for N-times (N is a natural number) fast forward reproduction of moving image encoded information for normal speed reproduction, comprising: A first encoder that performs encoding to satisfy a predetermined normal reproduction bit rate by a moving image encoding method that combines inner encoding and inter-frame encoding to generate normal-speed reproduction moving image encoding information; From each moving image frame constituting the moving image ,
By counting the number of frames,
Have means to take out only image frames
A second encoder that encodes each video frame for each frame using an intra-frame encoding method so as to satisfy a predetermined fast-forward playback bit rate, and generates video encoding information for fast-forward playback; Means for synchronizing the start and end of encoding between two encoders. 2. A method for encoding moving picture encoded information for normal speed reproduction.
N (N is a natural number) video encoding information for fast forward playback
An apparatus for creating a report, wherein each moving image frame constituting a moving image is encoded in a frame.
Video encoding method using both encoding and inter-frame encoding.
Encoding to satisfy the fixed normal playback bit rate
The first code that generates video coding information for normal speed playback
From a moving image frame and each moving image frame constituting the moving image.
Moving image frame every N frames by interval timer
Means for taking out only the video frames
Frame using a predetermined fast-forward playback
Video for fast forward playback
The second encoder for generating image encoding information and the synchronization of encoding start and end between the two encoders
Features and to Brighter Altai <br/> arm forward reproduction moving image coding information creating apparatus that includes a means for taking. Against the wherein the video encoding information for normal-speed playback
N (N is a natural number) video encoding information for fast forward playback
An apparatus for creating a report, wherein each moving image frame constituting a moving image is encoded in a frame.
Video encoding method using both encoding and inter-frame encoding.
Encoding to satisfy the fixed normal playback bit rate
The first code that generates video coding information for normal speed playback
And each of the moving image frames constituting the moving image
All video frames are coded by intra-frame coding
After that, the header information describing each frame coding information
Information and extract only coded information for every N frames
Encoding information extracted every N frames
Second encoder which uses video encoding information for fast-forward playback
And the synchronization of the coding start and end between the two encoders
Features and to Brighter Altai <br/> arm forward reproduction moving image coding information creating apparatus that includes a means for taking.