Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1999-03-18
2004-04-27
Tran, Thai (Department: 2615)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06728469
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a video signal reproduction apparatus and method for reproducing a video signal which has been prediction-recorded in the time axis direction on a recording medium and in particular, to a video signal reproduction apparatus and method that can preferably be used for high-speed (fast) reproduction of a video signal recorded on a recording medium.
2. Description of the Prior Art
A so-called digital video disc (hereinafter, referred to as DVD) has been known as a recording medium such as an optical disc having a digital video signal and a digital audio signal recorded thereon.
The DVD format uses a cell as a basic unit for reproducing contents of information. The cell consists of smaller reproduction units of 0.4 to 1.2 seconds, which unit is called Video Object Unit (VOBU). This smallest reproduction unit VOBU has at its head a control information pack called a navigation pack, NV_PCK. The NV_PCK contains a presentation control information (PCI) and a data search information (DSI). These information items are used as a VOBU address information for scanning before and after the smallest reproduction unit, VOBU.
FIG. 1
shows a data configuration of the DVD format. As shown in this
FIG. 1
, a main video data, a sub video data, and an audio data are managed in the video object set (VOBS). The VOBS is, for example, a unit of one movie work. A VOBS consists of a plurality of vide object (VOB). The VOB is a group of data recorded on a disc. Moreover, the VOBS consists of a plurality of Cell. The Cell, for example, corresponds to one scene or one cut of a movie. One Cell lasts several minutes to several tens of minutes. Moreover, the DVD can use a multi-story function which enables to represent one movie in a plurality of stories, or a parental lock function which skips a violence scene or other undesirable scene for education. These functions are created by combination of the Cells.
As has been described above, one Cell consists of a plurality of video object unit (VOBU). This VOBU contains, for example, one GOP (group of pictures) in the MPEG format. It should be noted that the MPEG has been discussed in the ISO-IEC/JTC1/SC2/WG11 and suggested as a standard specification. The MPEG is a hybrid data compression specification using the motion prediction coding and the discrete cosine transform (DCT) coding in combination. The GOP (group of pictures) of the MPEG specification contained in the aforementioned VOBU contains an intra-frame prediction coding picture (I picture), an inter-frame forward direction prediction coding pictures (P picture), and an inter-frame bidirectional prediction coding pictures (B picture). For example, a GOP consisting of 15 frames contains one frame of I picture, four frames of P picture, and ten frames of B picture.
FIG. 2A
shows a configuration example of the inter-frame prediction in the MPEG method when a GOP consists of 15 frames.
In
FIG. 2A
, the I picture is an intra-frame prediction coding picture which has been prediction coded within one frame; the P picture is an inter-frame forward prediction coding picture which performs prediction by referencing a temporally preceding frame (I picture or P picture); and the B picture is a bidirectional prediction coding picture which performs prediction by referencing temporally preceding and following frames.
That is, as indicated by arrows, the I picture I
2
is prediction coded within that frame; the P picture P
5
is prediction coded by referencing the I picture I
2
; the Picture P
8
is prediction coded by referencing the P picture P
5
. Furthermore; B pictures B
3
and B
4
are inter-frame prediction coded by referencing two pictures, i.e., the I picture I
2
and the P picture P
5
; the B picture B
6
and B
7
are inter-frame coded by referencing two P pictures P
5
and P
8
. Similarly, the other pictures are prediction coded and created. It should be noted that each subscribed numeric represents a temporary reference (hereinafter, referred to as TR). This TR picture sequence in the GOP and in a normal video reproduction, the frames are reproduced in this TR sequence.
The pictures thus prediction coded are decoded as follows. An I picture which has been prediction coded within a frame can be decoded with the I picture alone. Decoding of a P picture which has been prediction coded by referencing a temporally preceding I picture or P picture requires the temporally preceding I picture or P picture. Decoding of a B picture which has been prediction coded by referencing temporally preceding and following I pictures or P pictures requires the temporally preceding and following I pictures or P pictures.
To scope with this, the pictures are rearranged as shown in
FIG. 2B
, so that the pictures required for decoding can be decoded in advance. That is, decoding of B pictures B
0
, B
1
requires an I picture or P picture in the preceding GOP and an I picture I
2
in the current GOP. Accordingly, the I picture I
2
is arranged before the B pictures B
0
, B
1
. Decoding of B pctures B
3
, B
4
requires the I picture I
2
and the P picture P
5
. Accordingly, the P picture P
5
is arranged before the B pictures B
3
, B
4
. Decoding of the B pictures B
6
, B
7
requires P pictures P
5
and P
8
. Accordingly, the P picture P
8
is arranged before the B pictures B
6
, B
7
. Decoding of B pictures B
9
, B
10
requires P pictures P
8
, and P
11
. Accordingly, the P picture P
11
is arranged to precede the B pictures B
9
, B
10
. Decoding of B pictures B
12
, B
13
requires P pictures P
11
and P
14
. Accordingly, P picture P
14
is arranged to precede the B pictures B
12
, B
13
. Thus, in the MPEG method, the decoding order is different from the presentation order.
For decoding, the aforementioned prediction coding and Huffman coding are used. Moreover, recording is performed with a variable bit rate (variable transfer rate). For example, a scene with a rapid motion or complicated image requires a large data amount, whereas a simple image or an almost still image requires a small data amount. When this fact is taken into consideration, making use of a variable bit rate variable up to a transfer rate of 9.8 Mbps for example, an average bit rate of 3.5 Mbps is sufficient to realize a picture quality which requires the twice higher rate if a fixed rate is used.
Referring back to
FIG. 1
, one VOBU is constituted by a navigation pack NV_PCK containing a control information containing a VOBU management information; a video pack V_PCK containing a main video; an audio pack A_PCK containing an audio data; and sub picture pack SP_PCK containing a sub video data. The V_PCK, A_PCK, and SP_PCK are respectively compressed by a format such as MEPG2 and recorded on an optical disc as a recording medium.
FIG. 3
shows a configuration of the navigation pack NV_PCK which is a control information pack contained at the head of a VOBU. As shown in this
FIG. 3
, the NV_PCK contains a pack header and system header which are followed by a PCI (presentation control information) packet and DSI (data search information) packet. The PCI packet and the DSI packet contain a PCI data and a DSI data, respectively.
Furthermore, although not depicted, the DSI data contains DSI_GI which is a DSI general information. This DSI_GI contains end addresses of the reference pictures (I picture and P picture) for each of the pictures of the aforementioned MPEG. More specifically, the DSI_GI contains VOBU_
1
STREF_EA which is the end address of the first reference picture within the VOBU, VOBU_
2
NDREF_EA which is the end address of the second reference picture within the VOBU, and VOBU_
3
RDREF_EA which is the end address of the third reference picture within the VOBU.
When performing a fast reproduction, for example, twice faster than the standard reproduction speed, the aforementioned NV_PCK address information can be used to reproduce parts of reference pictures (I picture and P picture) within one GOP of the MPEG specification consisting of a plurality of video packs (V_
Ogawa Kenji
Okazaki Toru
Chieu Po-lin
Frommer William S.
Frommer & Lawrence & Haug LLP
Mahr Hans R.
Sony Corporation
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