[FFmpeg-trac] #4709(avcodec:new): Support mjpeg 4:2:2 encoding in rows of one block instead of two blocks

[FFmpeg]

#4709: Support mjpeg 4:2:2 encoding in rows of one block instead of two blocks
---------------------------------------+-----------------------------------
               Reporter:  cehoyos      |                  Owner:
                   Type:  enhancement  |                 Status:  new
               Priority:  wish         |              Component:  avcodec
                Version:  git-master   |               Keywords:  mjpeg rtp
             Blocked By:               |               Blocking:
Reproduced by developer:  0            |  Analyzed by developer:  0
---------------------------------------+-----------------------------------
 Sending FFmpeg-encoded 4:2:2 mjpeg is currently impossible because
 vsample[] is 2,2,2. RFC 2435 requires 4:2:2 mjpeg over rtp to be encoded
 with vsample[] 1,1,1.
 {{{
 $ ffmpeg -i fate-suite/lena.pnm -vcodec mjpeg -pix_fmt yuvj422p -f rtp
 rtp://127.0.0.1:5004
 ffmpeg version N-73450-ge83ffb4 Copyright (c) 2000-2015 the FFmpeg
 developers
   built with gcc 4.7 (SUSE Linux)
   configuration: --enable-gpl
   libavutil      54. 28.100 / 54. 28.100
   libavcodec     56. 46.101 / 56. 46.101
   libavformat    56. 40.100 / 56. 40.100
   libavdevice    56.  4.100 / 56.  4.100
   libavfilter     5. 20.100 /  5. 20.100
   libswscale      3.  1.101 /  3.  1.101
   libswresample   1.  2.100 /  1.  2.100
   libpostproc    53.  3.100 / 53.  3.100
 Input #0, image2, from 'fate-suite/lena.pnm':
   Duration: 00:00:00.04, start: 0.000000, bitrate: 39333 kb/s
     Stream #0:0: Video: ppm, rgb24, 256x256, 25 tbr, 25 tbn, 25 tbc
 [swscaler @ 0x2636220] deprecated pixel format used, make sure you did set
 range correctly
 Output #0, rtp, to 'rtp://127.0.0.1:5004':
   Metadata:
     encoder         : Lavf56.40.100
     Stream #0:0: Video: mjpeg, yuvj422p(pc), 256x256, q=2-31, 200 kb/s, 25
 fps, 90k tbn, 25 tbc
     Metadata:
       encoder         : Lavc56.46.101 mjpeg
 Stream mapping:
   Stream #0:0 -> #0:0 (ppm (native) -> mjpeg (native))
 SDP:
 v=0
 o=- 0 0 IN IP4 127.0.0.1
 s=No Name
 c=IN IP4 127.0.0.1
 t=0 0
 a=tool:libavformat 56.40.100
 m=video 5004 RTP/AVP 26
 b=AS:200

 Press [q] to stop, [?] for help
 [rtp @ 0x2641ce0] Only 1x1 chroma blocks are supported. Aborted!
 frame=    1 fps=0.0 q=4.1 Lsize=       0kB time=00:00:00.04 bitrate=
 5.6kbits/s
 video:14kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: unknown
 }}}

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Ticket URL: <https://trac.ffmpeg.org/ticket/4709>
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