2. Basic matters

2.1 Terms and symbols

(1) Configuration of MPEG device

MPEG Device ─┬─ MPEG Decoder ───── ┬─ MPEG / Video Decoder │ └─ MPEG / Audio Decoder ├─ MPEG Frame Buffer ─── Set of Frame Banks └─ MPEG Sector Buffer ──── Set of MPEG Sectors

(2) Definition of terms

Table 2.1 shows the definitions of the terms used.

MPEG

Abbreviation for Moving Picture Experts Group, which refers to the ISO / IEC JTC1 / SC29 / WG11 committee. As a standard, it is an international standard for high-efficiency coding for moving images.

MPEG buffer

MPEG / Video Memory area managed by LSI.

MPEG frame buffer

Area where the decoded image data is stored.
It is composed of multiple frame banks (number of faces).

Output mode	resolution	Number of faces
NTSC normal resolution	352 x 240	4
PAL normal resolution	352 x 288	3
NTSC high-definition still image	704 x 480	1
PAL high-definition still image	704 x 576	1

Frame bank

Area where the image data for one picture of the MPEG video stream is expanded.

Framebuffer window

A rectangular area set for the MPEG framebuffer.
This area is the output target.

Display window

A rectangular area on the display (TV monitor) where MPEG video is output.
The data of the frame buffer window is output.

Image data

24-bit full-color data per pixel obtained by decoding an MPEG video stream.
It is transferred to the host area as 15-bit color data.

Image data window

A rectangular area for accessing image data defined in the MPEG frame buffer.

Bright spot

The smallest display unit (one point) on the display.

Pixel

Display unit of image data. It is composed of multiple bright spots.
Normal resolution: 2x2 bright spots, high-definition resolution: 1x1 bright spots

System layer

An MPEG stream in which video and audio are synchronized and multiplexed.
(Multiplex stream)

Video layer

An MPEG stream consisting only of video data.

Audio layer

An MPEG stream consisting only of audio data.

Picture

One screen data.

I picture

Intra-coded image. It is encoded only by the information in the frame.

P picture

Forward prediction coded image. It is coded by predictions from past I, P pictures.

B picture

Bidirectional predictive coded image. Encoded by predictions from past or future I, P pictures.

D picture

DC-coded image. It has only a DC component and is used for searching.

GOP

A set of multiple pictures, including at least one I picture at the beginning.
Random access is possible for each GOP.
It usually consists of pictures of about 0.5 seconds (15 pictures).

field

1 Display screen of vertical scanning section. (NTSC: 60Hz, PAL: 50Hz)

flame

One display screen. A normal TV consists of two fields.

Interlace

Jump scan method. One display screen is composed of two fields, an even field and an odd field.

Non-interlaced

Sequential scanning method. One display screen is composed of one field.

PSC (framebuffer start code)

Picture layer start code. (00000100H)

SHC (Sequence Header Code)

The start code for the video sequence layer. (000001B3H)

SEC (system end code) │ │

Code that means the end of the system layer stream. (000001B9H)
It is specified as iso_11172_end_code.
* SEC may be used as an abbreviation for sequence end code (000001B7H), but in this manual, it is used as an abbreviation for system end code.

Timecode (TC)

Information that indicates the time from the beginning of the sequence.

Timestamp (PTS)

Time management information for playback output of each frame.
For PTS, the time stamp for decoding time management is called DTS.

Temporary reference (TR)

Information indicating the display order in the GOP. A 1024 remainder value that is reset at the beginning of the GOP.

VBV buffer

Area used to decode an MPEG video stream.
Reserved in the MPEG buffer.

STD buffer size

The buffer size specified by the system target decoder. Before starting playback, it is necessary to secure data for this buffer size.

WBC

A block that manages the decode bank and display bank.
Indicates the contents of the MPEG frame buffer waiting to be displayed (decoded).

Pause

Please stop decoding. As a result, the screen output also stops.

Freeze

Please stop the screen output. The decoding operation continues.

Decode sync signal (DSYNC)

Decoding instruction given from the host to the decoder during host synchronous playback.
Send instead of VSYNC as the decoding timing.

MPEG sector

MPEG sector A unit of data for accessing an MPEG buffer in buffer mode. (2048 bytes)
The MPEG sector buffer is configured as a set of MPEG sectors.

MPEG sector position

MPEG sector The location of the MPEG sector in the buffer.
It takes a value of 0 to (total number of MPEG sectors-1).
The MPEG sector is accessed using the MPEG sector position as a key.

(3) List of symbols and abbreviations

2.2 MPEG-1 standard

For the MPEG-1 standard, refer to the following standard.

Table 2.3 List of MPEG-1 standards

Item	Standard	Standard name
MPEG-1 standard	ISO / IEC 11172	1993 Information technology --Coding of moving pictures and associated audio for digital storage media up to about 1.5 Mbit / s
MPEG / System layer	ISO / IEC 11172-1	Same as above --Part1: Systems
MPEG / Video layer	ISO / IEC 11172-2	Same as above-Part2: Video
MPEG / Audio layer	ISO / IEC 11172-3	Same as above-Part3: Audio