[FFmpeg-trac] #5874(avcodec:open): tiff LZW compression does not compress enough

[FFmpeg]

#5874: tiff LZW compression does not compress enough
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             Reporter:  jsteinkamp  |                    Owner:
                 Type:  defect      |                   Status:  open
             Priority:  normal      |                Component:  avcodec
              Version:  git-master  |               Resolution:
             Keywords:  tif         |               Blocked By:
             Blocking:              |  Reproduced by developer:  1
Analyzed by developer:  0           |
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Comment (by jsteinkamp):

 jsteinkamp Replying to [ticket:5874 jsteinkamp]:
 HI, I tested this bug again.
 The LZW compression for TIFF is still larger than photoshop.
 photoshop file 716 KB, ffmpeg file 884KB
 The file was 32 bit 1024x768 included an alpha channel

 ffmpeg version: N-91024-g293a6e8332

 built with gcc 7.3.0 (GCC)
   configuration: --enable-gpl --enable-version3 --enable-sdl2 --enable-
 bzlib --e
 nable-fontconfig --enable-gnutls --enable-iconv --enable-libass --enable-
 libblur
 ay --enable-libfreetype --enable-libmp3lame --enable-libopencore-amrnb
 --enable-
 libopencore-amrwb --enable-libopenjpeg --enable-libopus --enable-libshine
 --enab
 le-libsnappy --enable-libsoxr --enable-libtheora --enable-libtwolame
 --enable-li
 bvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-
 libx265 --en
 able-libxml2 --enable-libzimg --enable-lzma --enable-zlib --enable-gmp
 --enable-
 libvidstab --enable-libvorbis --enable-libvo-amrwbenc --enable-libmysofa
 --enabl
 e-libspeex --enable-libxvid --enable-libaom --enable-libmfx --enable-amf
 --enabl
 e-ffnvcodec --enable-cuvid --enable-d3d11va --enable-nvenc --enable-nvdec
 --enab
 le-dxva2 --enable-avisynth
   libavutil      56. 18.100 / 56. 18.100
   libavcodec     58. 19.101 / 58. 19.101
   libavformat    58. 13.102 / 58. 13.102
   libavdevice    58.  4.100 / 58.  4.100
   libavfilter     7. 21.100 /  7. 21.100
   libswscale      5.  2.100 /  5.  2.100
   libswresample   3.  2.100 /  3.  2.100
   libpostproc    55.  2.100 / 55.  2.100
 Input #0, tiff_pipe, from 'hibiscus1.0001.tif':
   Duration: N/A, bitrate: N/A
     Stream #0:0: Video: tiff, rgba, 1024x768 [SAR 1:1 DAR 4:3], 25 tbr, 25
 tbn,
 25 tbc
 Stream mapping:
   Stream #0:0 -> #0:0 (tiff (native) -> tiff (native))
 Press [q] to stop, [?] for help
 Output #0, image2, to 'hibiscus1.0001.tif':
   Metadata:
     encoder         : Lavf58.13.102
     Stream #0:0: Video: tiff, rgba, 1024x768 [SAR 1:1 DAR 4:3], q=2-31,
 200 kb/s
 , 25 fps, 25 tbn, 25 tbc
     Metadata:
       encoder         : Lavc58.19.101 tiff
 frame=    1 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
 speed=0.526x

 video:883kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB
 muxing o
 verhead: unknown

 > Summary of the bug:tiff LZW compression might not compress enough
 > How to reproduce:
 > ffmpeg -y -i b.tif -pix_fmt rgb24 -vcodec tiff -compression_algo lzw
 test_24.tif
 > The file made in ffmepg is 59.2 MB, if I resave the file in photoshop it
 is 39.8 MB
 > ffmpeg version
 > N-78598-g98a0053
 > Patches should be submitted to the ffmpeg-devel mailing list and not
 this bug tracker.

--
Ticket URL: <https://trac.ffmpeg.org/ticket/5874#comment:5>
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