7. MPEG data specifications

Describe constants, data types, access macros, etc. used in the MPEG communication interface.

(1) Format

In the figure, the reserved area is represented by "-". Be sure to specify 0 for the reserved area.

7.1 MPEG data list

Table 7.1 shows a list of data for the MPEG communication interface.

Table 7.1 MPEG data list

data		Data name	number
constant		Constant	20.0
Status and MPEG reports		Status & MPEG Report	21.0
	MPEG operation status	actst	21.1
	Operating interval counter	vcnt	21.2
	Picture information	pict	21.3
	MPEG / Audio status	stat_a	21.4
	MPEG / Video status	stat_v	21.5
MPEG interrupt factor flag		Intreq	22.0
Data type			23.0
	MPEG status information	CdcMpStat	23.1
	Timecode	CdcMpTc	23.2
	MPEG decoder connection destination parameter	CdcMpCon	23.3
	MPEG stream parameters	CdcMpStm	23.4
	Screen special effects parameters	CdcMpVeff	23.5

7.2 MPEG data details

7.2.1 Constant

List

Title Data specifications

Data constant

Data Name Constant

No 20.0

(1) Error code (MPEG part)

Constant name	explanation
CDC_ERR_MP_COMU	The MPCM flag is not set to 1 when the command is issued.

(2) Next stream flag

The following function is used to select the current and next streams.

• CDC_MpSetCon
• CDC_MpGetCon
• CDC_MpSetStm
• CDC_MpGetStm

Constant name	explanation
CDC_MPSTF_CUR	Specifying the current connection destination / stream
CDC_MPSTF_NEXT	Specifying the next connection destination / stream

(3) Maximum window size and coordinates

The following function is used to set the size and coordinates of the window.

• CDC_MpSetWinFpos
• CDC_MpSetWinDpos
• CDC_MpSetWinDsiz
• CDC_MpSetImgPos
• CDC_MpSetImgSiz

Each maximum value is different for NTSC / PAL system and normal / high-definition output.

Constant name	value	explanation
CDC_MPNT_NSX	352	NTSC	Usual	size	X direction
CDC_MPNT_NSY	240				Y direction
CDC_MPNT_NPX	351			Coordinate	X direction
CDC_MPNT_NPY	239				Y direction
CDC_MPNT_HSX	704		High-definition	size	X direction
CDC_MPNT_HSY	480				Y direction
CDC_MPNT_HPX	703			Coordinate	X direction
CDC_MPNT_HPY	479				Y direction
CDC_MPPL_NSX	352	PAL	Usual	size	X direction
CDC_MPPL_NSY	288				Y direction
CDC_MPPL_NPX	351			Coordinate	X direction
CDC_MPPL_NPY	287				Y direction
CDC_MPPL_HSX	704		High-definition	size	X direction
CDC_MPPL_HSY	576				Y direction
CDC_MPPL_HPX	703			Coordinate	X direction
CDC_MPPL_HPY	575				Y direction

7.2.2 Status and MPEG Report (MPEG Status Information)

List

Title Data specifications

Data Status and MPEG reports

Data Name Status & MPEG Report

No 21.0

(1) MPEG status information

The response of the MPEG command does not return a CD report. Usually, it often returns an MPEG Report. Whether to return an MPEG report as a report or other information depends on the command. (Regular response always returns a CD report.)
The status and MPEG report are collectively called MPEG status information.

byte 0 1 2 3 4 5 6 7    
     + -------- + -------- + -------- + -------- + -------- + ---- ---- + -------- + -------- +
     | Status | Report |
     + -------- + -------- + -------- + -------- + -------- + ---- ---- + -------- + -------- +

(2) MPEG Report

MPEG report during REJECT is invalid, and valid during WAIT.

MPEG Report
byte 1 2 3 4 5 6    
     + -------- + -------- + -------- + -------- + -------- + ---- ---- +
     actst | vcnt | pict | stat_a | stat_v |
     + -------- + -------- + -------- + -------- + -------- + ---- ---- +
     actst: MPEG operation status vcnt: Operation interval (VSYNC) counter pict: Picture information stat_a: MPEG / Audio status stat_v: MPEG / Video status 

List

Title Data specifications

Data MPEG operation status

Data Name actst

No 21.1

(1) MPEG operation status

    bit 7 6 5 4 3 2 1 0
       ┌─┬─┬─┬─┬─┬─┬─┬─┐
  actst │ − │ │ │ │ Initial value: 19H
       └─┴─┴─┴─┴─┴─┴─┴─┘
       │ │ │
       │ │ └──── MPEG / Video operating status │ │
       │ └──────── MPEG decoding status │ CDC_MPASTD_STOP 1: Stop 0: Decoding │
       └──────────── MPEG / Audio operating status

(2) Operating state of MPEG decoder

For the state transition, refer to " 5.1.2 State transition of transfer block ".

MPEG / Video operating status		MPEG / Audio operating status		explanation
Constant name	value	Constant name	value
CDC_MPSTV_STOP	01H	CDC_MPSTA STOP	10H	Stop
CDC_MPSTV_PREP1	02H	CDC_MPSTA PREP1	20H	Preparation 1
CDC_MPSTV_PREP2	03H	CDC_MPSTA PREP2	30H	Preparation 2
CDC_MPSTV_TRNS	04H	CDC_MPSTA TRNS	40H	Transfer (playback)
CDC_MPSTV_CHNG	05H	CDC_MPSTA CHNG	50H	switching
CDC_MPSTV_RCV	06H	CDC_MPSTA RCV	60H	Resurrection processing

(3) MPEG decoding state

1 represents a stopped state, and 0 represents a decoding state. The state transition diagram is shown below.

Picture start code input ┌─────┐──────────── → ┌─────┐
Initial state │ Stopped │ │ Decoding │
└─────┘ ← ────────────└─────┘
Sequence end input 

List

Title Data specifications

Data Operating interval counter

Data Name vcnt

No 21.2

A counter that increases by 1 for each VSYNC. When the initialization function of the MPEG decoder (CDC_MpInit) is executed, it is cleared to 0.
When decoding by host synchronization, executing the CDC_MpOutDsync function increases this value by 2.

List

Title Data specifications

Data Picture information

Data Name pict

No 21.3

(1) Picture information

    bit 7 6 5 4 3 2 1 0
       ┌─┬─┬─┬─┬─┬─┬─┬─┐
   pict │ − │ − │ − │ − │ − │ │ Initial value: 00H
       └─┴─┴─┴─┴─┴─┴─┴─┘
└── Picture type being decoded

(2) Picture type

The picture type when the decoder detects the picture start code.
If the decoder is stopped, you will get the type of picture that is waiting to be decoded.

Constant name	explanation
CDC_MPPICT_I	I picture
CDC_MPPICT_P	P picture
CDC_MPPICT_B	B picture
CDC_MPPICT_D	D picture

List

Title Data specifications

Data MPEG / Audio status

Data Name stat_a

No 21.4

(1) MPEG / Audio status

    bit 7 6 5 4 3 2 1 0
       ┌─┬─┬─┬─┬─┬─┬─┬─┐
 stat_a │ │ │ │ │ │ │ − │ − │ │
       └┬┴┬┴┬┴┬┴┬┴─┴─┴┬┘
       │ │ │ │ │ └─CDC_MPSTA_DEC 1: Decoding operation │ │ │ │ └─────── CDC_MPSTA_ILG 1: Audio illegal │ │ │ └───────── │ │ └─────────── CDC_MPSTA_ERR 1: Audio error occurred │ └───────────── CDC_MPSTA_OUTL 1: Left channel output └─────── ──────── CDC_MPSTA_OUTR 1: Right channel output

(2) Meaning of each flag

bit	flag	explanation
0	Audio decoding operation	Indicates that the audio decoder is operating. (0: Stopped)
3	Audio illegal	Indicates that there is an abnormality in the MPEG / Audio layer, sampling frequency, and bit rate.
4	Audio buffer partition empty	Indicates that the audio buffer partition is empty and there is no stream data for audio playback.
5	Audio error	Indicates an audio-related error. The error cause can be obtained by the CDC_MpGetInt function.
6	Left channel output	Indicates that the left channel is being output. (0: Mute)
7	Right channel output	Indicates that the right channel is being output. (0: Mute)

The value of each flag is updated on a VSYNC basis.

List

Title Data specifications

Data MPEG / Video status

Data Name stat_v

No 21.5

(1) MPEG / Video status

    bit 7 6 5 4 3 2 1 0
       ┌─┬─┬─┬─┬─┬─┬─┬─┐
 stat_v │ │ │ │ │ │ │ │ │ │ │
       └┬┴┬┴┬┴┬┴┬┴┬┴┬┴┬┘
       │ │ │ │ │ | │ └─────── CDC_MPSTV_FREEZE 1: Freezing │ │ │ │ └───────── CDC_MPSTV_LSTPIC 1: Final picture display │ │ └─────────── CDC_MPSTV_FIELD 1 : Odd field │ └───────────── CDC_MPSTV_UPDPIC 1: Picture updated └─────────────── CDC_MPSTV_ERR 1: Video error occurred bit 15 14 13 12 11 10 9 8
       ┌─┬─┬─┬─┬─┬─┬─┬─┐
 stat_v │ │ − │ − │ │ │ − │ − │ │
       └┬┴─┴─┴┬┴┬┴─┴─┴┬┘
       │ │ │ └─ CDC_MPSTV_RDY 1: Ready for output │ │ └─────── CDC_MPSTV_1STPIC 1: Displaying the first picture ──────────── Indefinite

(2) Meaning of each flag

bit	flag	explanation
0	Video decoding operation	Indicates that the video decoder is operating. (0: Stopped) When this flag is 1, if there is a free frame bank, the decoder decodes in that bank.
1	Picture display	Indicates that the decoded picture is being displayed.
2	Pause	Indicates that the video decoder is paused.
3	Freeze	Indicates that the video decoder is freezing.
4	Final picture display	Indicates that the currently displayed picture is the last picture in the stream.
5	Odd field (frame sync signal)	Indicates that the odd field is being displayed. (1: Even field) When outputting to VDP2, the frame starts from an odd number field and becomes one frame with two fields.
6	Picture update	Indicates that the picture has been updated. 2 Changes in operation section units (VSYNC x 2 or CDC_MpOutDsync). It becomes 1 when the display is updated and when the picture is discarded in the frozen state.
7	Video error	Indicates that a video-related error has occurred. The error cause can be obtained by the CDC_MpGetInt function.
8	Ready for output	Indicates that the image can be output. When the number of decoded frame banks is two (I, P), it becomes 1. When decoding is started in the paused state, the output ready flag is set to 1 without being displayed. As soon as frame advance is performed in this state, the first image is output.
11	First picture display	Indicates that the currently displayed picture is the first picture in the stream. The head is the order on the media or the decoding, not the display order.
12	Video buffer partition empty	Indicates that the video buffer partition is empty and there is no stream data for video playback.

The value of each flag is updated on a VSYNC basis.

7.2.3 MPEG interrupt factor flag

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List

Title Data specifications

Data MPEG interrupt factor flag

Data Name Intreq

No 22.0

The cause of the MPEG interrupt is notified by the CDC_MpGetInt function in the following format (4 bytes).
The same bit arrangement is used when masking interrupts with the CDC_MpSetIntMsk function.

MPEG interrupt factor flag byte 0 1 2 3
    ┌─────┬─────┬─────┬─────┐
    │ − │ Audio │ Video │
    │ │ Interrupt │ Interrupt │
    └─────┴─────┴─────┴─────┘

In the following explanatory diagram, V / A shall represent video / audio, respectively.

(1) Video interrupt

bit 7 6 5 4 3 2 1 0
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ │ │ │ │ │ │ │ │ Initial value: 00H
   └┬┴┬┴┬┴┬┴┬┴┬┴┬┴┬┘
   │ │ │ │ │ │ │ │ └─ CDC_MPINT_VSRDY 1: V stream ready
   │ │ │ │ │ │ └─── CDC_MPINT_VSCHG 1: V stream switching completed
   │ │ │ │ │ └───── CDC_MPINT_VORDY 1: Ready for video output
   │ │ │ │ └─────── CDC_MPINT_VOSTRT 1: Start video output
   │ │ │ └───────── CDC_MPINT_VDERR 1: Video decoding error
   │ │ └─────────── CDC_MPINT_VSERR 1: V stream data error
   │ └───────────── CDC_MPINT_VBERR 1: V buffer partition connection error
   └─────────────── CDC_MPINT_VNERR 1: Next V stream data error


bit 15 14 13 12 11 10 10 9 
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ │ │ │ │ │ │ │ │ Initial value: 00H
   └┬┴┬┴┬┴┬┴┬┴┬┴┬┴┬┘
   │ │ │ │ │ │ │ │ └─ CDC_MPINT_PSTRT 1: Picture start detection
   │ │ │ │ │ │ └─── CDC_MPINT_GSTRT 1: GOP start detection
   │ │ │ │ │ └───── CDC_MPINT_SQEND 1: Sequence end detection
   │ │ │ │ └─────── CDC_MPINT_SQSTRT 1: Sequence start detection
   │ │ │ └───────── CDC_MPINT_VTRG 1: V sector trigger bit detection
   │ │ └─────────── CDC_MPINT_VEOR 1: EOR bit detection of V sector
   │ └───────────── CDC_MPINT_ATRG 1: A sector trigger bit detection
   └─────────────── CDC_MPINT_AEOR 1: EOR bit detection of A sector

(2) Audio interrupt

bit 23 22 21 20 21 20 19 18
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ │ │ │ │ │ │ │ │ Initial value: 00H
   └┬┴┬┴┬┴┬┴┬┴┬┴┬┴┬┘
   │ │ │ │ │ │ │ │ └─ CDC_MPINT_ASRDY 1: A stream ready
   │ │ │ │ │ │ └─── CDC_MPINT_ASCHG 1: A stream switching completed
   │ │ │ │ │ └───── CDC_MPINT_AORDY 1: Ready for audio output
   │ │ │ │ └─────── CDC_MPINT_AOSTRT 1: Start audio output
   │ │ │ └───────── CDC_MPINT_ADERR 1: Audio decoding error
   │ │ └─────────── CDC_MPINT_ASERR 1: A stream data error
   │ └───────────── CDC_MPINT_ABERR 1: A buffer partition connection error
   └─────────────── CDC_MPINT_ANERR 1: Next A stream data error

(3) Video interrupt factor

bit flag

0 Video stream ready

Indicates that data of (STD buffer size + 16KB) or more is stored in the video buffer partition. (For automatic forwarding)

1 Video stream switching completed

Indicates that the next stream has started to be transferred to the VBV buffer.

2 Ready for video output

It shows that two pictures are decoded in the frame buffer and can be output in the next operation section. Check with field interrupt and interrupt the host. (Valid only once before switching streams)

3 Start video output

Indicates that the first picture of the video stream has been output. (Valid even after switching streams)

4 Video decoding error

Indicates that a decoding error has occurred in the video LSI.

5 Video stream data error

Indicates that an error has occurred in the stream being played. (Data other than video exists in the buffer partition)

6 Video buffer partition connection error

Indicates that the buffer partition and the decoder were disconnected while transferring data from the buffer partition.

7th video stream data error

Indicates that an error has occurred in the next stream. (Data other than video exists in the next buffer partition)

8 Picture start detection

Indicates that a picture start code (PSC) has been detected.

9 GOP start detection

Indicates that the GOP start code has been detected.

10 Sequence end detection

Indicates that a sequence end code has been detected.

11 Sequence start detection

Indicates that a sequence start code has been detected.

>

12 Video sector trigger bit detection

Indicates that a trigger bit in the video sector subheader was detected before the backward aperture.

13 Video sector EOR bit detection

Indicates that the EOR bit in the video sector subheader was detected before the backward aperture.

14 Audio sector trigger bit detection

Indicates that a trigger bit in the audio sector subheader was detected before the backward aperture.

15 Audio sector EOR bit detection

Indicates that the EOR bit in the audio sector subheader was detected before the backward aperture.

16 Audio stream ready

Indicates that data of one sector or more is stored in the audio buffer partition.

17 Audio stream switching completed

Indicates that the next stream has started to be transferred to the audio decoder.

18 Ready for audio output

Indicates that the stream data has started to be transferred to the audio decoder. (Valid only once before switching streams)

19 Start audio output

Indicates that the stream data has started to be transferred to the audio decoder. (Valid even after switching streams)

20 Audio decoding error

Indicates that a decoding error has occurred in the audio LSI.

21 Audio stream data error

Indicates that an error has occurred in the stream being played. (Data other than audio exists in the buffer partition)

22 Audio buffer partition connection error

Indicates that the buffer partition and the decoder were disconnected while transferring data from the buffer partition.

23 Next audio stream data error

Indicates that an error has occurred in the next stream. (Data other than audio exists in the next buffer partition)

7.2.4 Data type

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List

Title Data specifications

Data MPEG status information

Data Name CdcMpStat

No 23.1

The CD block status and the MPEG report are collectively called MPEG status information.

(1) MPEG status information …… CDC_MpGetCurStat, CDC_MpGetLastStat functions

CdcMpStat * mpstat

Access macro	Mold	explanation
CDC_MPSTAT_STS (mpstat)	Uint8	Status (see CD part)
CDC_MPSTAT_AST (mpstat)	Uint8	MPEG operation status
CDC_MPSTAT_VCNT (mpstat)	Uint16	Operating interval (VSYNC) counter
CDC_MPSTAT_PICT (mpstat)	Uint8	Picture information
CDC_MPSTAT_STA (mpstat)	Uint8	MPEG / Audio status
CDC_MPSTAT_STV (mpstat)	Uint16	MPEG / Video status

(2) Related macros

Access macro	explanation
CDC_MPGET_STC (mpstat)	Get status code from MPEG status information
CDC_MPGET_ASTV (mpstat)	Get MPEG / Video operating status from MPEG status information
CDC_MPGET_ASTA (mpstat)	Get MPEG / Audio operating status from MPEG status information

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List

Title Data specifications

Data Timecode

Data Name CdcMpTc

No 23.2

(1) Time code …… CDC_MpGetTc function

CdcMpTc * mptc

Access macro	Mold	explanation
CDC_MPTC_HOUR (mptc)	Uint8	Time (0-23)
CDC_MPTC_MIN (mptc)	Uint8	Minutes (0-59)
CDC_MPTC_SEC (mptc)	Uint8	Seconds (0-59)
CDC_MPTC_PIC (mptc)	Uint8	Picture (0-63)

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List

Title Data specifications

Data MPEG decoder connection destination parameter

Data Name CdcMpCon

No 23.3

(1) MPEG decoder connection destination parameter …… CDC_MpSetCon, CDC_MpGetCon function

CdcMpCon * mpcon

Access macro	Mold	explanation
CDC_MPCON_CMOD (mpcon)	Uint8	Connection mode
CDC_MPCON_LAY (mpcon)	Uint8	Layer specification and picture search specification
CDC_MPCON_BN (mpcon)	Uint8	Buffer partition number

(2) MPEG / Audio connection mode

bit 7 6 5 4 3 2 1 0
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ − │ − │ − │ − │ │ │ │ Initial value: 00H Unchanged: CDC_PARA_NOCHG
   └┬┴─┴─┴─┴─┴┬┴┬┴┬┘
   │ │ │ └─ CDC_MPCMOD_EOR 1: Switch by EOR detection │ │ └─── CDC_MPCMOD_SEC 1: Switch by SEC detection │ └───── CDC_MPCMOD_DEL 1: Erase sectors in partition ────── 1: Do not change the setting 0: Change

(3) MPEG / Video connection mode

bit 7 6 5 4 3 2 1 0
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ │ │ │ │ │ │ │ Initial value: 00H Unchanged: CDC_PARA_NOCHG
   └┬┴┬┴─┴─┴┬┴┬┴┬┴┬┘
   │ │ │ │ │ │ └─CDC_MPCMOD_EOR 1: Switch by EOR detection │ │ │ │ │ └─── CDC_MPCMOD_SEC 1: Switch by SEC detection │ │ │ │ └───── │ │ └─────── CDC_MPCMOD_IGPTS 1: Do not identify PTS │ │ └────────── Video decode buffer clear method │ │ 0 (00B): Do not clear │ │ 1 (01B) ): Clear VBV (CDC_MPCMOD_VCLR)
   │ │ 2 (10B): Clear VBV + WBC (CDC_MPCMOD_VWCLR)
   │ └───────────── CDC_MPCMOD_BEF (Always specify 0 for GAME-CD)
   └─────────────── 1: Do not change the setting 0: Change

Constant name	explanation
CDC_MPCMOD_EOR CDC_MPCMOD_SEC	Specify the conditions for natural switching. Each bit of EOR bit / SEC (system end code) detection can be combined according to the OR condition. If the next stream is not registered, this condition becomes the end condition.
CDC_MPCMOD_DEL	When decoding, the sectors in the buffer partition are erased. (0: Hold)
CDC_MPCMOD_IGPTS	Transfer sectors to the decoder without identifying the PTS. Sectors without PTS can also be transferred. However, inconsistency occurs in audio / video synchronization.
CDC_MPCMOD_VCLR CDC_MPCMOD_VWCLR	Specify the clear method of the video decode buffer when connecting to the starting stream. It is not a clear method when switching. It is valid only when setting the current connection destination.
CDC_MPCMOD_BEF	The end condition is judged in front of the rear throttle. Be sure to specify 0 for normal GAME-CD. 0 is always returned when the value is acquired. (For Video CD only)

(4) MPEG / Audio layer designation

Access macro	Mold	explanation
CDC_MPLAY_SYS	00H	System layer …… Initial value
CDC_MPLAY_AUDIO	01H	Video layer

(5) MPEG / Video layer designation and picture search designation

Picture search is a search for SHC (sequence header code) in a video stream.

bit 7 6 5 4 3 2 1 0
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ − │ − │ − │ − │ − │ │ Initial value: 00H
   └─┴─┴─┴─┴─┴─┴─┴┬┘
   │ └─ Layer designation └────────────── Picture search designation

(a) Layer designation

Constant name	value	explanation
CDC_MPLAY_SYS	00H	System layer …… Initial value
CDC_MPLAY_VIDEO	01H	Video layer

(b) Picture search specification

Specify the picture search when connecting to the starting stream.
It is not a picture search at the time of switching. It is valid only when setting the current connection destination.

Constant name	value	explanation
CDC_MPSRCH_OFF	00H	Do not perform picture search …… Initial value
CDC_MPSRCH_VIDEO	80H	Do a picture search
CDC_MPSRCH_AV	C0H	Discard audio data according to picture search

(6) Buffer partition number

Specifies the buffer partition number to which the audio or video decoder is connected.
You can undo the setting by specifying CDC_NUL_SEL for the buffer partition. However, the setting cannot be canceled depending on the operating state of the MPEG decoder. (It becomes WAIT.)

stream	Cancelable state	Irreversible state
Starting stream	Stop, prepare 1, prepare 2	Transfer (play), switch, revive
Next stream	Stop, prepare 1, prepare 2, transfer	switching

Use the CDC_MpChgCon function to disconnect (kill) the starting stream in the transfer (playback) state.

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List

Title Data specifications

Data MPEG stream parameters

Data Name CdcMpStm

No 23.4

Used when setting / acquiring the stream number and channel number of the stream to be decoded.

(1) MPEG stream parameters: CDC_MpSetStm, CDC_MpGetStm functions

CdcMpStm * mpstm

Constant name	value	explanation
CDC_MPSTM_SMOD (mpstm)	Uint8	Stream mode
CDC_MPSTM_ID (mpstm)	Uint8	Stream number (stream ID)
CDC_MPSTM_CN (mpstm)	Uint8	Channel number

(2) Stream mode

bit 7 6 5 4 3 2 1 0
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ − │ │ │ − │ − │ │ │ Initial value: 00H Unchanged: CDC_PARA_NOCHG
   └┬┴─┴┬┴┬┴─┴─┴┬┴┬┘
   │ │ │ │ └─CDC_MPSMOD_SNSET 1: Set the stream number │ │ │ └─── CDC_MPSMOD_SNIDF 1: Identify the stream number │ │ └────────── Do │ └─────────── CDC_MPSMOD_CNIDF 1: Identify the channel number └─────────────── 1: Do not change the setting 0: Change 

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List

Title Data specifications

Data Screen special effects parameters

Data Name CdcMpVeff

No 23.5

(1) Screen special effect parameter …… CDC_MpSetVeff function

CdcMpVef * mpvef

Constant name	value	explanation
CDC_MPVEF_ITP (mpvef)	Uint8	Interpolation mode
CDC_MPVEF_TRP (mpvef)	Uint8	Transparent bit mode
CDC_MPVEF_MOZH (mpvef)	Uint8	Horizontal mosaic mode
CDC_MPVEF_MOZV (mpvef)	Uint8	Vertical mosaic mode
CDC_MPVEF_SOFTH (mpvef)	Uint8	Horizontal blur mode
CDC_MPVEF_SOFTV (mpvef)	Uint8	Vertical blur mode

(2) Interpolation mode

Specifies whether to interpolate in the horizontal and vertical directions for the luminance (Y) and color difference (C).

bit 7 6 5 4 3 2 1 0
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ − │ − │ − │ │ │ │ │ Initial value: 00H Unchanged: CDC_PARA_NOCHG
   └┬┴─┴─┴─┴┬┴┬┴┬┴┬┘
   │ │ │ │ └─CDC_MPITP_YH 1: Horizontal interpolation of Y │ │ │ └─── CDC_MPITP_CH 1: Horizontal interpolation of C │ │ └───── CDC_MPITP_YV 1: Vertical interpolation of Y ─────── CDC_MPITP_CV 1: Perform vertical interpolation of C └─────────────── 1: Do not change the setting 0: Change

(3) Transparent bit mode

When the brightness of each pixel is less than or equal to the specified brightness level, the transparency bit of the MPEG register is set to 1.
The transparent area is also called a priority area.

bit 7 6 5 4 3 2 1 0
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ − │ − │ − │ − │ │ │ Initial value: 00H Unchanged: CDC_PARA_NOCHG
   └┬┴─┴─┴─┴─┴┬┴─┴─┘
   │ │ │
   │ │ └── Brightness level │ └───── CDC_MPTRP_MAG 1: Enlarge the transparent area └─────────────── 1: Do not change the setting 0: Change

(a) Luminance level

Constant name	value	explanation
CDC_MPTRP_DFL	00H	Normal (no transparent bit processing)
CDC_MPTRP_64	01H	Brightness 64
CDC_MPTRP_96	02H	Brightness 96
CDC_MPTRP_128	03H	Brightness 128

(4) Mosaic mode (horizontal / vertical direction)

value	explanation
00H	Normal (no mosaic) …… Initial value
01H ~ 0AH (n) 00H	2 to the nth root (2,4,8,16,32,64,128,256,512,1024 times)
FFH	Do not change the setting (CDC_PARA_NOCHG)

(5) Blur mode (horizontal / vertical direction)

bit 7 6 5 4 3 2 1 0
   ┌─┬─┬─┬─┬─┬─┬─┬─┐
   │ │ − │ − │ − │ − │ − │ − │ │ Initial value: 00H Unchanged: CDC_PARA_NOCHG
   └┬┴─┴─┴─┴─┴─┴─┴┬┘
   │ └─CDC_MPSOFT_ON 1: Blur └─────────────── 1: Do not change the setting 0: Change

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★ PROGRAMMER'S GUIDE ★ CD communication I / F (MPEG part)

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Copyright SEGA ENTERPRISES, LTD., 1997