[FFmpeg-user] Decoder flag "gray" seem to not work

[Andrey Utkin]

2014-02-18 16:19 GMT+02:00 Carl Eugen Hoyos <cehoyos at ag.or.at>:
> Andrey Utkin <andrey.krieger.utkin <at> gmail.com> writes:
>
>>
>> I think this has problems with decoding:
>>
>>  $ ffmpeg -flags gray  -i ~/test.ts
>
> Please test -flags +gray
>
>> -filter:v format=pix_fmts=gray
>> -vcodec libx264  /tmp/gray.ts
>
> Is -vcodec libx264 needed to reproduce the crash?
> Does it also crash for the following?
> $ ffmpeg -flags +gray -i test.ts -f null -
>
> Note that your configure options look broken to me,
> please always test without --extra-cflags before
> reporting problems.
>
> If it still fails, please provide the input sample.

It looks to work the way you proposed. It plays non-colored picture on
green background. Sometimes the green background is not green, i think
it's due to color-coding planes being not initialized, which is
intentional.
Both h264 and mpeg4 video decoders work this way.
Thank you.

 $ ./ffmpeg -flags +gray -i
http://ftp.nluug.nl/pub/graphics/blender/demo/movies/Sintel.2010.720p.mkv
-an -f mpegts - | ffplay -
ffmpeg version N-60377-g7ea8ca2 Copyright (c) 2000-2014 the FFmpeg developers
  built on Feb 18 2014 17:01:54 with gcc 4.6.3 (Gentoo 4.6.3 p1.13, pie-0.5.2)
  configuration: --disable-stripping --enable-debug --enable-gray
  libavutil      52. 63.100 / 52. 63.100
  libavcodec     55. 49.101 / 55. 49.101
  libavformat    55. 30.100 / 55. 30.100
  libavdevice    55.  7.100 / 55.  7.100
  libavfilter     4.  1.102 /  4.  1.102
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
ffplay version N-60377-g7ea8ca2 Copyright (c) 2003-2014 the FFmpeg developers
  built on Feb 11 2014 18:21:19 with gcc 4.6.3 (Gentoo 4.6.3 p1.13, pie-0.5.2)
  configuration: --enable-gpl --enable-libx264
--enable-encoder=libx264 --disable-stripping --enable-debug
--extra-cflags='-O0 -g -ggdb' --enable-libopus --enable-libvpx
--enable-x11grab --enable-libfreetype --enable-filter=drawtext
  libavutil      52. 63.100 / 52. 63.100
  libavcodec     55. 49.101 / 55. 49.101
  libavformat    55. 30.100 / 55. 30.100
  libavdevice    55.  7.100 / 55.  7.100
  libavfilter     4.  1.102 /  4.  1.102
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
  libpostproc    52.  3.100 / 52.  3.100
Input #0, matroska,webm, from
'http://ftp.nluug.nl/pub/graphics/blender/demo/movies/Sintel.2010.720p.mkv':
  Metadata:
    encoder         : libebml v1.0.0 + libmatroska v1.0.0
    creation_time   : 2011-04-24 17:20:33
  Duration: 00:14:48.03, start: 0.000000, bitrate: 6071 kb/s
    Chapter #0.0: start 0.000000, end 103.125000
    Metadata:
      title           : Chapter 01
    Chapter #0.1: start 103.125000, end 148.667000
    Metadata:
      title           : Chapter 02
    Chapter #0.2: start 148.667000, end 349.792000
    Metadata:
      title           : Chapter 03
    Chapter #0.3: start 349.792000, end 437.208000
    Metadata:
      title           : Chapter 04
    Chapter #0.4: start 437.208000, end 472.075000
    Metadata:
      title           : Chapter 05
    Chapter #0.5: start 472.075000, end 678.833000
    Metadata:
      title           : Chapter 06
    Chapter #0.6: start 678.833000, end 744.083000
    Metadata:
      title           : Chapter 07
    Chapter #0.7: start 744.083000, end 888.032000
    Metadata:
      title           : Chapter 08
    Stream #0:0(eng): Video: h264 (High), yuv420p(tv, bt709),
1280x544, SAR 1:1 DAR 40:17, 24 fps, 24 tbr, 1k tbn, 48 tbc
    Stream #0:1(eng): Audio: ac3, 48000 Hz, 5.1(side), fltp, 640 kb/s
    Metadata:
      title           : AC3 5.1 @ 640 Kbps
    Stream #0:2(ger): Subtitle: subrip
    Stream #0:3(eng): Subtitle: subrip
    Stream #0:4(spa): Subtitle: subrip
    Stream #0:5(fre): Subtitle: subrip
    Stream #0:6(ita): Subtitle: subrip
    Stream #0:7(dut): Subtitle: subrip
    Stream #0:8(pol): Subtitle: subrip
    Stream #0:9(por): Subtitle: subrip
    Stream #0:10(rus): Subtitle: subrip
    Stream #0:11(vie): Subtitle: subrip
Output #0, mpegts, to 'pipe:':
  Metadata:
    encoder         : Lavf55.30.100
    Chapter #0.0: start 0.000000, end 103.125000
    Metadata:
      title           : Chapter 01
    Chapter #0.1: start 103.125000, end 148.667000
    Metadata:
      title           : Chapter 02
    Chapter #0.2: start 148.667000, end 349.792000
    Metadata:
      title           : Chapter 03
    Chapter #0.3: start 349.792000, end 437.208000
    Metadata:
      title           : Chapter 04
    Chapter #0.4: start 437.208000, end 472.075000
    Metadata:
      title           : Chapter 05
    Chapter #0.5: start 472.075000, end 678.833000
    Metadata:
      title           : Chapter 06
    Chapter #0.6: start 678.833000, end 744.083000
    Metadata:
      title           : Chapter 07
    Chapter #0.7: start 744.083000, end 888.032000
    Metadata:
      title           : Chapter 08
    Stream #0:0(eng): Video: mpeg2video, yuv420p, 1280x544 [SAR 1:1
DAR 40:17], q=2-31, 200 kb/s, 90k tbn, 24 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (h264 -> mpeg2video)
Press [q] to stop, [?] for help
Input #0, mpegts, from 'pipe:':    0KB vq=    0KB sq=    0B f=0/0
  Duration: N/A, start: 1.441667, bitrate: N/A
  Program 1
    Metadata:
      service_name    : Service01
      service_provider: FFmpeg
    Stream #0:0[0x100]: Video: mpeg2video (Main) ([2][0][0][0] /
0x0002), yuv420p(tv), 1280x544 [SAR 1:1 DAR 40:17], max. 104857 kb/s,
24 fps, 24 tbr, 90k tbn, 48 tbc

-- 
Andrey Utkin