[Ffmpeg-devel] [FWD] [PATCH] immediate decoding of dvd stills

[Nico Sabbi]

Michael Niedermayer wrote:

> 
> ok, see below, i hope it makes sense as iam tired if not ill retry tomorow
> 
> (S=still image, E=seq end, please correct me if some assumtion is wrong)
> 
> as stored:               I0 P3 B1 B2 P6 B4 B5 P7 S8 E9 IA PD BB BC
> decoding with your code:    I0 B1 B2 P3 B4 B5 P6 S8    S8?IA BB BC
> what should be output:      I0 B1 B2 P3 B4 B5 P6 P7 S8    IA BB BC
> 
> your code looses the last frame before the still image (iam assuming that
> this shouldnt happen, but i dunno, maybe iam wrong in what spec is the
> still picture stuff?)
> 
> [...]

I didn't find a formal definition of still image in the 
specs (there's only written that sequence_end_code 
terminates a sequence), but they are generally coded as:

sequence header+all sequence_extension headers
I frame with temp_ref=0
sequence_end

so in your example S8 would be S0


00000000: sequence hdr: 720x576, a/f:23, bitrate=22500
0000004c: sequence extension hdr, frame rate extension: 1/1
00000056: sequence display extension hdr
00000062: GOP: 0:00:00.00, closed
0000006a: picture hdr, frametype=I, temporal=0
00000072: picture coding extension hdr, top trf=2
0000cc29: sequence end code
0000cc2d: sequence hdr: 720x576, a/f:23, bitrate=22500
0000cc79: sequence extension hdr, frame rate extension: 1/1
0000cc83: sequence display extension hdr
0000cc8f: GOP: 0:00:00.00, closed
0000cc97: picture hdr, frametype=I, temporal=0
0000cc9f: picture coding extension hdr, top trf=2
00017d82: sequence end code
00017d86: sequence hdr: 720x576, a/f:23, bitrate=22500
00017dd2: sequence extension hdr, frame rate extension: 1/1
00017ddc: sequence display extension hdr
00017de8: GOP: 0:00:00.00, closed
00017df0: picture hdr, frametype=I, temporal=0
00017df8: picture coding extension hdr, top trf=2
000242d1: sequence end code