[FFmpeg-trac] #1702(swscale:new): Transparency information gets lost when converting from gray8a to rgba

[FFmpeg]

#1702: Transparency information gets lost when converting from gray8a to rgba
-------------------------------------+-------------------------------------
               Reporter:  cehoyos    |                  Owner:
                   Type:  defect     |                 Status:  new
               Priority:  normal     |              Component:  swscale
                Version:  git-       |               Keywords:  gray8a
  master                             |  alpha
             Blocked By:             |               Blocking:
Reproduced by developer:  0          |  Analyzed by developer:  0
-------------------------------------+-------------------------------------
 (Second part of ticket #769)
 When converting from gray8a to rgba, the resulting picture is opaque.
 {{{
 $ ffmpeg -s 32x32 -pix_fmt gray8a -i gray8a.yuv -pix_fmt rgba out.png
 ffmpeg version N-44015-g5e363bb Copyright (c) 2000-2012 the FFmpeg
 developers
   built on Aug 30 2012 10:41:45 with gcc 4.5.3 (GCC)
   configuration: --cc=/usr/local/gcc-4.5.3/bin/gcc
   libavutil      51. 70.100 / 51. 70.100
   libavcodec     54. 54.100 / 54. 54.100
   libavformat    54. 25.104 / 54. 25.104
   libavdevice    54.  2.100 / 54.  2.100
   libavfilter     3. 14.100 /  3. 14.100
   libswscale      2.  1.101 /  2.  1.101
   libswresample   0. 15.100 /  0. 15.100
 [rawvideo @ 0x1480400] Estimating duration from bitrate, this may be
 inaccurate
 Input #0, rawvideo, from 'gray8a.yuv':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: rawvideo (Y2[0][8] / 0x8003259), gray8a, 32x32, 25
 tbr, 25 tbn, 25 tbc
 Output #0, image2, to 'out.png':
   Metadata:
     encoder         : Lavf54.25.104
     Stream #0:0: Video: png, rgba, 32x32, q=2-31, 200 kb/s, 90k tbn, 25
 tbc
 Stream mapping:
   Stream #0:0 -> #0:0 (rawvideo -> png)
 Press [q] to stop, [?] for help
 Truncating packet of size 2048 to 1
 frame=    1 fps=0.0 q=0.0 Lsize=       0kB time=00:00:00.04 bitrate=
 0.0kbits/s
 video:0kB audio:0kB subtitle:0 global headers:0kB muxing overhead
 -100.000000%
 }}}

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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/1702>
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