[FFmpeg-user] Combine 2 small GIF images to small animated GIF, fails with "Decoder (codec none) not found for input stream #0:0"

[Jim DeLaHunt]

Hello, FFMPEG folks:

I have two simple GIF images, and I want to combine them into a 2-frame 
animated GIF. This is to give me a reduced input file to diagnose 
another FFMpeg issue.

However, when I do the obvious command, I get an error, "Decoder (codec 
none) not found for input stream #0:0".

How can I make a simple 2-frame animate GIF out of my two still GIF 
images blue_1.gif and blue_2.gif?

% ls -lF blue_[0-9].gif
-rw-r--r--  1 myuser  staff  1303  6 Jan 21:04 blue_1.gif
-rw-r--r--  1 myuser  staff  1379  6 Jan 21:05 blue_2.gif

% ffmpeg -f image2 -i blue_%d.gif  -y animated_blue_12.gif
ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
   built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
   configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-avresample
--enable-libmp3lame --enable-libvorbis --enable-libopus --enable-librsvg --enable-libtheora
--enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libsoxr --enable-libspeex
--enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype
--enable-libfribidi --disable-indev=jack --enable-opencl --disable-outdev=xv --enable-audiotoolbox
--enable-videotoolbox --enable-sdl2 --mandir=/opt/local/share/man --enable-shared --enable-pthreads
--cc=/usr/bin/clang --arch=x86_64 --enable-x86asm --enable-libx265 --enable-gpl --enable-postproc
--enable-libx264 --enable-libxvid
   libavutil      55. 78.100 / 55. 78.100
   libavcodec     57.107.100 / 57.107.100
   libavformat    57. 83.100 / 57. 83.100
   libavdevice    57. 10.100 / 57. 10.100
   libavfilter     6.107.100 /  6.107.100
   libavresample   3.  7.  0 /  3.  7.  0
   libswscale      4.  8.100 /  4.  8.100
   libswresample   2.  9.100 /  2.  9.100
   libpostproc    54.  7.100 / 54.  7.100
[image2 @ 0x7ff99080ba00] Could not find codec parameters for stream 0 (Video: none, none): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, image2, from 'blue_%d.gif':
   Duration: 00:00:00.08, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: none, none, 25 tbr, 25 tbn, 25 tbc
Stream mapping:
   Stream #0:0 -> #0:0 (? (?) -> gif (native))
Decoder (codec none) not found for input stream #0:0

How can I get past this problem?  Maybe specify the image format, but how?

The documentation for the image2 format demuxer[1] does not appear to 
say how the image2 demuxer identifies the image file formats that it 
reads. Still, the extension is .gif, which I expect would be enough of a 
hint.

The error message mentions the 'analyzeduration' options (default value 
5,000,000 microseconds) and 'probesize' options (default value 5000000 
bytes). Both these values are quite large for single-frame 1300-byte 
GIFs.  But setting them to small values doesn't change anything:

% ffmpeg -f image2 -analyzeduration 0 -probesize 1000 -i blue_%d.gif  -y animated_blue_12.gif
ffmpeg version 3.4.1 Copyright (c) 2000-2017 the FFmpeg developers
   built with Apple LLVM version 8.0.0 (clang-800.0.42.1)
   configuration: --prefix=/opt/local --enable-swscale --enable-avfilter --enable-avresample --enable-libmp3lame --enable-libvorbis --enable-libopus --enable-librsvg --enable-libtheora --enable-libopenjpeg --enable-libmodplug --enable-libvpx --enable-libsoxr --enable-libspeex --enable-libass --enable-libbluray --enable-lzma --enable-gnutls --enable-fontconfig --enable-libfreetype --enable-libfribidi --disable-indev=jack --enable-opencl --disable-outdev=xv --enable-audiotoolbox --enable-videotoolbox --enable-sdl2 --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --arch=x86_64 --enable-x86asm --enable-libx265 --enable-gpl --enable-postproc --enable-libx264 --enable-libxvid
   libavutil      55. 78.100 / 55. 78.100
   libavcodec     57.107.100 / 57.107.100
   libavformat    57. 83.100 / 57. 83.100
   libavdevice    57. 10.100 / 57. 10.100
   libavfilter     6.107.100 /  6.107.100
   libavresample   3.  7.  0 /  3.  7.  0
   libswscale      4.  8.100 /  4.  8.100
   libswresample   2.  9.100 /  2.  9.100
   libpostproc    54.  7.100 / 54.  7.100
[image2 @ 0x7f9c5580a600] Could not find codec parameters for stream 0 (Video: none, none): unknown codec
Consider increasing the value for the 'analyzeduration' and 'probesize' options
Input #0, image2, from 'blue_%d.gif':
   Duration: 00:00:00.08, start: 0.000000, bitrate: N/A
     Stream #0:0: Video: none, none, 25 tbr, 25 tbn, 25 tbc
Stream mapping:
   Stream #0:0 -> #0:0 (? (?) -> gif (native))
Decoder (codec none) not found for input stream #0:0

Again, how can I make a simple 2-frame animated GIF out of my two still 
GIF images blue_1.gif and blue_2.gif?

[1] http://ffmpeg.org/ffmpeg-all.html#image2-1

Thanks in advance for your help. Best regards,
     —Jim DeLaHunt

-- 
     --Jim DeLaHunt, jdlh at jdlh.com     http://blog.jdlh.com/ (http://jdlh.com/)
       multilingual websites consultant

       355-1027 Davie St, Vancouver BC V6E 4L2, Canada
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