Motion video signal processing for recording or reproducing – Local trick play processing – With randomly accessible medium
Reexamination Certificate
1999-03-18
2003-01-28
Chevalier, Robert (Department: 2712)
Motion video signal processing for recording or reproducing
Local trick play processing
With randomly accessible medium
C386S349000
Reexamination Certificate
active
06512881
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 from a recording medium containing a video signal prediction-coded in the time axis direction and in particular, to a video signal reproduction apparatus and method preferably used for performing a forward direction slow reproduction and forward direction stepped reproduction of a video signal recorded on a recording medium.
2. Description of Prior Art
A so-called digital video disc (hereinafter, referred to as DVD) is known as a recording medium of an optical disc containing a digital video signal and a digital audio signal recorded.
This DVD is formatted in cells as basic units for reproducing information contents. Each of the cells consists of a reproduction unit of 0.4 to 1.2 seconds called a video object unit (VOBU). At the head of VOBU, a navigation pack NV_PCK is allocated as a control information pack. This 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 a VOBU as the aforementioned reproduction minimum unit
Here,
FIG. 3
shows a data configuration of the aforementioned DVD format. as shown in this
FIG. 3
, a unit of a video object set (VOB) is used for management of a main video data, sub video data, and an audio data. This VOBS, for example, includes a whole one work. The VOBS consists of a plurality of video objects (VOB's). The VOB consists of a group of data items recorded on a disc. Each VOBS consists of a plurality of cells. Each cell represents a single scene or one cut in a movie. One cell lasts 10 seconds or so. Moreover, the DVD has a function of a multi-story format for showing one movie in a plurality of stories, or a function of a so-called parental lock for skipping an educationally unacceptable scene such as violence. These functions are created by combination of these cells.
One cell consists of a plurality of video object units (VOBU's). Each VOBU is a unit of 0.4 to 1.2 seconds of a moving picture. This VOBU contains, for example, one GOP (Group of Pictures) in a so-called MPEG format. It should be noted that the MPEG is a hybrid data compression standard suggested by ISO-IEC/JTC1/SC2/WG11 and uses a motion compensation predictive coding in combination with discrete cosine transform (DCT). The GOP (group of pictures) of MPEG standard contained in the VOBU consists of intra-frame predictive coding pictures (I picture), inter-frame forward predictive coding pictures (P pictures), and inter-frame bidirectional predictive coding pictures (B pictures). For example, if one GOP consists of 15 frames, the GOP contains one frame of I picture, four frames of P picture, and 10 frames of B picture.
FIG. 6A
shows a configuration example of inter-frame prediction in the MPEG method when one GOP consists of 15 frames, for example.
In this
FIG. 6A
, the I picture is an intra-frame predictive coding picture which is predictive-coded within a frame; the P picture is an inter-frame forward predictive coding picture which performs prediction referencing a temporally preceding coded picture (I picture or P picture); and the B picture is a bidirectional predictive coding picture which performs prediction referencing two frames, i.e., temporally preceding and following pictures.
That is, as shown by arrows, I picture I
2
is intra-frame prediction coded within the frame; P picture P
5
is inter-frame prediction coded by referencing the I picture I
2
; and a P picture P
8
is inter-frame 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 picture I
2
and P picture P
5
; and B pictures B
6
and B
7
are inter-frame prediction coded by referencing two pictures, P picture P
5
and P picture P
8
. In the same way, the other pictures are prediction coded. It should be noted that the subscription number of each picture represents a temporary reference (hereinafter, referred to as TR). This TR indicates the frame sequence within GOP. In a normal video reproduction, the frames are reproduced in this TR sequence.
When decoding the pictures thus coded, the decoding is performed as follows. In the case of I picture which has been prediction coded within a frame, the I picture alone can be decoded. However, in the P picture which has been prediction coded by referencing a temporally preceding I picture or P picture, a temporally preceding I picture or P picture is required for decoding. In the case of B picture which has been prediction coded by referencing two pictures temporally preceding and following, its decoding requires an I picture or P picture temporally preceding and following.
For this, pictures are arranged as shown in
FIG. 6B
so that pictures required for decoding are decoded beforehand. That is, decoding of B pictures B
0
and B
1
requires an I picture or P picture in a preceding GOP and the I picture I
2
in the current GOP. Accordingly, the I picture I
2
is arranged prior to the B pictures B
0
and B
1
. Decoding of B pictures B
3
and B
4
requires the I picture I
2
and P picture P
5
. Accordingly, the P picture P
5
is arranged prior to the B pictures B
3
and B
4
. Decoding of B pictures B
6
and B
7
requires the P picture P
5
and the P picture P
8
. Accordingly, the P picture P
8
is arrange prior to the B pictures B
6
and B
7
. Decoding of B pictures B
9
and B
10
requires P pictures P
8
and P
11
. Accordingly, the P picture P
11
is arranged prior to the B pictures B
9
and B
10
. Decoding of B pictures B
12
and B
13
requires P pictures P
11
and P
14
. Accordingly, the P picture P
14
is arranged prior to the B pictures B
12
and B
13
. Thus, in the MPEG method, the decoding order is different from the presentation order of the frames.
Referring back to
FIG. 3
, each VOBU contains a navigation pack NV_PCK which is a control information having a VOBU management information, a video pack V_PCK which is a pack having a main video data, an audio pack A_PCK having an audio data, and a sub picture pack SP_PCK which is a pack having a sub video data. The V_PCK, A_PCK, and SP_PCK are compressed in the MPEG2 format or the like and recorded on an optical disc as a recording medium.
FIG. 8
shows a configuration of a navigation pack NV_PCK which is control information pack arrange at the head of a VOBU. As shown in
FIG. 8
, the NV_PCK contains a Pack header and a System header followed by a Presentation control information (PCI) and a Data search information (DSI). The PCI packet contains a PCI data, and the DSI packet contains a DSI data.
Furthermore, the DSCI data contains a DSI general information DSI_GI (not depicted). This DSI_GI contains end addresses of the reference pictures (I picture and P picture) in the MPEG pictures, i.e., VOBU
—
1STREF_EA which is the end address of the first reference picture in the VOBU, VOBU
—
2NDREF_EA which is the end address of the second reference picture in the VOBU, and VOBU
—
3RSREF_EA which is the end address of the second reference picture in the VOBU.
On the other hand, as shown in
FIG. 9
, a video signal consists of a top field and a bottom field that constitute a frame as a unit. In a normal Play mode, reproduction of the top field is performed before the bottom field.
This video signal using as a unit the pair of two pictures, i.e., top field and bottom field, is applied to, for example, to a skip scan, a so-called interlace method. It should be noted that there is also a progressive method which scans the scan lines one after another without skipping a scan line.
In a conventional video signal reproduction apparatus, the forward slow reproduction (SlowF) or forward stepped reproduction (StepF), as shown in
FIG. 9
, only the top fields are reproduced one after another. That is, a top field of one frame is followed by the top field of the next frame, skipping the bottom field of the current frame.
Kinebuchi Naoyuki
Okazaki Toru
Chevalier Robert
Frommer William S.
Frommer & Lawrence & Haug LLP
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