[FFmpeg-trac] #9077(swscale:open): yuv420 -> rgb32 broken on altivec (was: image not rendered correctly, vertical bars missing)

FFmpeg trac at avcodec.org
Sat Jan 23 15:41:27 EET 2021


#9077: yuv420 -> rgb32 broken on altivec
------------------------------------+-----------------------------------
             Reporter:  pocock      |                    Owner:
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  swscale
              Version:  git-master  |               Resolution:
             Keywords:  ppc         |               Blocked By:
             Blocking:              |  Reproduced by developer:  1
Analyzed by developer:  0           |
------------------------------------+-----------------------------------
Changes (by cehoyos):

 * status:  new => open
 * reproduced:  0 => 1
 * component:  undetermined => swscale
 * priority:  important => normal
 * keywords:  cat => ppc


Comment:

 For future tickets:
 Please test current FFmpeg git head, the only version supported on this
 bug tracker and please always provide all information here on the bug
 tracker, do not use external resources except for large input files.

 Workaround is to convert to rgb24.

 {{{
 $ ffmpeg -f lavfi -i testsrc2 -vframes 1 -pix_fmt rgba out.png
 ffmpeg version N-100746-gd8a585d Copyright (c) 2000-2021 the FFmpeg
 developers
   built with gcc 8.3.1 (GCC) 20190304 (Advance-Toolchain-at12.0) [revision
 269374]
   configuration: --enable-gpl --cc=/opt/at12.0/bin/gcc
   libavutil      56. 63.101 / 56. 63.101
   libavcodec     58.117.101 / 58.117.101
   libavformat    58. 65.101 / 58. 65.101
   libavdevice    58. 11.103 / 58. 11.103
   libavfilter     7. 96.100 /  7. 96.100
   libswscale      5.  8.100 /  5.  8.100
   libswresample   3.  8.100 /  3.  8.100
   libpostproc    55.  8.100 / 55.  8.100
 Input #0, lavfi, from 'testsrc2':
   Duration: N/A, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: rawvideo (I420 / 0x30323449), yuv420p, 320x240
 [SAR 1:1 DAR 4:3], 25 tbr, 25 tbn, 25 tbc
 Stream mapping:
   Stream #0:0 -> #0:0 (rawvideo (native) -> png (native))
 Press [q] to stop, [?] for help
 [swscaler @ 0x2c840490] ALTIVEC: Color Space RGBA
 Output #0, image2, to 'out.png':
   Metadata:
     encoder         : Lavf58.65.101
     Stream #0:0: Video: png, rgba(pc, progressive), 320x240 [SAR 1:1 DAR
 4:3], q=2-31, 200 kb/s, 25 fps, 25 tbn
     Metadata:
       encoder         : Lavc58.117.101 png
 frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
 speed=0.626x
 video:10kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing overhead: unknown
 }}}
 Output is visually broken.
 On Power6, Power7 etc. this is a regression since
 8dcbfb73d58c06fa012db5ffea97647fed95a280

--
Ticket URL: <https://trac.ffmpeg.org/ticket/9077#comment:2>
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