[FFmpeg-trac] #1728(undetermined:new): Alpha gets destroyed when transcoding Prores4444 to Prores4444

FFmpeg trac at avcodec.org
Wed Sep 12 14:18:47 CEST 2012


#1728: Alpha gets destroyed when transcoding Prores4444 to Prores4444
-------------------------------------+-------------------------------------
             Reporter:  rmk          |                     Type:  defect
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 I made a transparent PNG using Gimp, imported that into a Final Cut Pro 7
 project and put it on a sequence configured to use Prores4444 as codec and
 exported the file which resulted in a one-frame Prores4444 file. I then
 verified that the resulting file still had the transparency by using it as
 an overlay in Final Cut.

 I then transcoded the file to Prores4444 again, this time using ffmpeg.
 Importing that video into Final Cut Pro and used that as an overlay which
 did not work (i.e. transparency was gone).

 Command line used (current ffmpeg with a patch Carl sent me on the ML
 today):


 ffmpeg -i ~/testdata/video/finalcut-
 output/prores4444_with_transparency.mov -vcodec prores_kostya -pix_fmt
 yuv444p10le -acodec copy
 ~/tmp/prores4444_with_transparency_ffmpeg_patched.mov
 ffmpeg version N-44391-gf9dd2e5 Copyright (c) 2000-2012 the FFmpeg
 developers
   built on Sep 12 2012 12:09:31 with gcc 4.2.1 (GCC) (Apple Inc. build
 5664)
   configuration:
   libavutil      51. 72.100 / 51. 72.100
   libavcodec     54. 55.100 / 54. 55.100
   libavformat    54. 26.101 / 54. 26.101
   libavdevice    54.  2.100 / 54.  2.100
   libavfilter     3. 16.103 /  3. 16.103
   libswscale      2.  1.101 /  2.  1.101
   libswresample   0. 15.100 /  0. 15.100
 Guessed Channel Layout for  Input Stream #0.1 : stereo
 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from '/Users/krueger/testdata/video
 /finalcut-output/prores4444_with_transparency.mov':
   Metadata:
     major_brand     : qt
     minor_version   : 537199360
     compatible_brands: qt
     creation_time   : 2012-09-12 08:48:56
   Duration: 00:00:00.04, start: 0.000000, bitrate: 43461 kb/s
     Stream #0:0(eng): Video: prores (ap4h / 0x68347061), yuv444p10le,
 1920x1080, 40697 kb/s, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 25 tbn, 25 tbc
     Metadata:
       creation_time   : 2012-09-12 08:48:56
       handler_name    : Apple Alias Data Handler
       timecode        : 01:00:00:00
     Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz,
 stereo, s16, 1536 kb/s
     Metadata:
       creation_time   : 2012-09-12 08:48:56
       handler_name    : Apple Alias Data Handler
     Stream #0:2(eng): Data: none (tmcd / 0x64636D74)
     Metadata:
       creation_time   : 2012-09-12 08:48:57
       handler_name    : Apple Alias Data Handler
       timecode        : 01:00:00:00
 Output #0, mov, to
 '/Users/krueger/tmp/prores4444_with_transparency_ffmpeg_patched.mov':
   Metadata:
     major_brand     : qt
     minor_version   : 537199360
     compatible_brands: qt
     encoder         : Lavf54.26.101
     Stream #0:0(eng): Video: prores (ap4h / 0x68347061), yuv444p10le,
 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 200 kb/s, 25 tbn, 25 tbc
     Metadata:
       creation_time   : 2012-09-12 08:48:56
       handler_name    : Apple Alias Data Handler
       timecode        : 01:00:00:00
     Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz,
 stereo, 1536 kb/s
     Metadata:
       creation_time   : 2012-09-12 08:48:56
       handler_name    : Apple Alias Data Handler
 Stream mapping:
   Stream #0:0 -> #0:0 (prores -> prores_kostya)
   Stream #0:1 -> #0:1 (copy)
 Press [q] to stop, [?] for help
 frame=    1 fps=0.0 q=0.0 Lsize=     141kB time=00:00:00.04
 bitrate=28897.2kbits/s
 video:132kB audio:8kB subtitle:0 global headers:0kB muxing overhead
 1.286356%

 I'll attach the Prores4444 file generated Final Cut Pro and the PNG used
 to create the video. If it would be more convenient for debugging this to
 have a video with a specific setup (e.g. smaller frame size, a specific
 pattern or color distribution), don't hesitate to tell me and I will
 produce it.

-- 
Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1728>
FFmpeg <http://ffmpeg.org>
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