Difference between revisions of "MVD Services"

Revision as of 21:04, 16 November 2014

This is for using the MVD hardware video decoder(unknown whether MVD can do more than decoding) + hardware color-format converter. The New_3DS Internet Browser uses mvd:STD for video decoding + YUV2RGB for decoded MJPEG frames.

See here for the supported hardware decoder video codecs.

A maximum of 4 sessions can be opened at a time, for all of these services combined.

MVD Service "mvd:STD"

Command Header	Available since system version	Description
0x00010082		Initialize
0x00020000		Shutdown
0x00030300		CalculateWorkBufSize
0x00050100		(u8 unk0, u8 unk1, u8 unk2, u8 unk3) SKATER uses value 0 for all of these params.
0x00070000
0x00080142		DecodeFrame
0x00090042		(u8 unkval, val0, kprocess handle) This writes some state beginning at cmdreply[2]. unkval is normally 0, when preparing to shutdown MVD unkval is 1.
0x000A0000
0x00180000
0x00190000
0x001A0000		Used when doing color-format conversion.
0x001B0040		(u8 unknown) SKATER uses value 1 for this.
0x001C0000
0x001D0042		GetConfig
0x001E0044		SetConfig

This one uses the I/O mapped @ 0x10207000.

This service is used by the New_3DS Internet Browser.

By default MVD does(?) various post-processing with the output image, this is controlled by the configuration. This post-processing isn't done at all in certain cases. By default MVD will align the output frame width to 512, by writing zero-value pixels.

Initialization procedures:

MJPEG: Use command MVDSTD:Initialize with bufsize=1, then command 0x00180000.
H.264: If needed, use MVDSTD:CalculateWorkBufSize. Then use MVDSTD:Initialize. Then use commands 0x00050100, 0x00180000, and 0x001B0040. Then use MVDSTD:DecodeFrame 3 times with unknown input data. Use command 0x000A0000, then use MVDSTD:DecodeFrame with unknown data.

Shutdown procedures:

MJPEG: just use command 0x00190000, then MVDSTD:Shutdown.
H.264: Use command 0x00090042 in a loop, waiting for it to return a retval that isn't 0x00017002. Then use commands 0x001C0000, 0x00190000, and 0x00070000. Then use MVDSTD:Shutdown.

MVD Service "l2b:u"

This one uses the I/O mapped @ 0x10130000.

MVD Service "l2b2:u"

This uses the same command-handler as "l2b:u".

MVD Service "y2r2:u"

This one uses the I/O mapped @ 0x10102000.

MVD Result-codes

Result-code	Internal MVD status-code	Description
0xD961710F		Invalid configuration, mainly when setting the config.

@@ Line 54: / Line 54: @@
 | 0x001A0000
 |
-| Used when doing MJPEG decoding?
+| Used when doing color-format conversion.
 |-
 | 0x001B0040
@@ Line 76: / Line 76: @@
 This service is used by the [[New_3DS]] [[Internet Browser]].
-Note that the hardware doesn't actually handle MJPEG, for that the hardware only does color format conversion. The input color format for that(with SKATER at least) is yuyv422, and the output color format is RGB565(this is probably determined by the [[MVDSTD:GetConfig|configuration]]).
 By default MVD does(?) various post-processing with the output image, this is controlled by the [[MVDSTD:GetConfig|configuration]]. This post-processing isn't done at all in certain cases. By default MVD will align the output frame width to 512, by writing zero-value pixels.