Opened 6 years ago

Closed 6 years ago

#5668 closed enhancement (wontfix)

webp : implement fancy filtering

Reported by: mvignali Owned by:
Priority: normal Component: swscale
Version: git-master Keywords:
Cc: Blocked By:
Blocking: Reproduced by developer: no
Analyzed by developer: no


Summary of the bug:
How to reproduce:

./ffmpeg -i ./rgb_webp_q80.webp res3.png
ffmpeg version N-80681-g4cc896e Copyright (c) 2000-2016 the FFmpeg developers
  built with Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
  configuration: --prefix=../build --disable-yasm --disable-ffplay --disable-ffprobe --disable-ffserver
  libavutil      55. 26.100 / 55. 26.100
  libavcodec     57. 46.100 / 57. 46.100
  libavformat    57. 40.101 / 57. 40.101
  libavdevice    57.  0.101 / 57.  0.101
  libavfilter     6. 46.102 /  6. 46.102
  libswscale      4.  1.100 /  4.  1.100
  libswresample   2.  1.100 /  2.  1.100
Input #0, webp_pipe, from './rgb_webp_q80.webp':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: webp, yuv420p(tv, bt470bg/unknown/unknown), 12x8, 25 tbr, 25 tbn, 25 tbc
[image2 @ 0x7f8ef1013800] Using AVStream.codec to pass codec parameters to muxers is deprecated, use AVStream.codecpar instead.
Output #0, image2, to 'res3.png':
    encoder         : Lavf57.40.101
    Stream #0:0: Video: png, rgb24, 12x8, q=2-31, 200 kb/s, 25 fps, 25 tbn, 25 tbc
      encoder         : Lavc57.46.100 png
Stream mapping:
  Stream #0:0 -> #0:0 (webp (native) -> png (native))
Press [q] to stop, [?] for help
frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A speed=  24x    
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown

Patches should be submitted to the ffmpeg-devel mailing list and not this bug tracker.

Attachments (2)

rgb_webp_q80.webp (100 bytes ) - added by mvignali 6 years ago.
rgb_webp_q80_reconvert.png (277 bytes ) - added by mvignali 6 years ago.
png output with dwebp

Download all attachments as: .zip

Change History (4)

by mvignali, 6 years ago

Attachment: rgb_webp_q80.webp added

by mvignali, 6 years ago

Attachment: rgb_webp_q80_reconvert.png added

png output with dwebp

comment:1 by mvignali, 6 years ago

Keywords: fancy added
Summary: webp : lossy decoding have lower quality than official decoderwebp : implement fancy filtering
Type: defectenhancement

After more tests :
if we output yuv frame from webp sample using ffmpeg or dwebp, the files are binary exact.

When converting webp file to png with ffmpeg, the result is very close to the output of dwebp using the nofancy option.
./dwebp rgb_webp_q80.webp -nofancy -o res.png

comment:2 by Carl Eugen Hoyos, 6 years ago

Component: avcodecswscale
Keywords: webm lossy fancy removed
Resolution: wontfix
Status: newclosed

Our software scaler does not try to copy WebP's behaviour.

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