Can't use image2pipe with PNG images

[eugeneware]

When I run the following command

$ cat file1.png file2.png | ffmpeg -y -f image2pipe -r 1 -vcodec png -i - out.mp4

I get the following error.

ffmpeg version 0.7.11, Copyright (c) 2000-2011 the FFmpeg developers

built on Apr 25 2012 19:55:19 with clang 3.0 (tags/Apple/clang-211.10.1)
configuration: --prefix=/opt/local --enable-gpl --enable-postproc --enable-swscale --enable-avfilter --enable-libmp3lame --enable-libvorbis --enable-libtheora --enable-libdirac --enable-libschroedinger --enable-libopenjpeg --enable-libxvid --enable-libx264 --enable-libvpx --enable-libspeex --mandir=/opt/local/share/man --enable-shared --enable-pthreads --cc=/usr/bin/clang --arch=x86_64 --enable-yasm --enable-nonfree --enable-libfaac
libavutil 50. 43. 0 / 50. 43. 0
libavcodec 52.123. 0 / 52.123. 0
libavformat 52.111. 0 / 52.111. 0
libavdevice 52. 5. 0 / 52. 5. 0
libavfilter 1. 80. 0 / 1. 80. 0
libswscale 0. 14. 1 / 0. 14. 1
libpostproc 51. 2. 0 / 51. 2. 0

[image2pipe @ 0x7f9dd104ac00] max_analyze_duration 5000000 reached at 5000000
[image2pipe @ 0x7f9dd104ac00] Estimating duration from bitrate, this may be inaccurate
Input #0, image2pipe, from 'pipe:':

Duration: N/A, bitrate: N/A

Stream #0.0: Video: png, 1 fps, 1 tbr, 1 tbn, 1 tbc

[buffer @ 0x7f9dd0c32780] Invalid pixel format string '-1'
Error opening filters!

This is a long standing issue. I found an old patch and updated it to work with the latest version of ffmpeg in the git repository.

Here's the fix:

 http://pastebin.com/5mTfGsdg

You can use the following as example png files to replicate the issue:

 http://dl.dropbox.com/u/4763380/ffmpeg/file1.png
 http://dl.dropbox.com/u/4763380/ffmpeg/file2.png

This problem has been hanging around for a long time. It would be great to finally get it patched into the main trunk.

[cehoyos]

Please consider sending patches to ffmpeg-devel, they get more attention there.

[cehoyos]

The patch was applied, thank you!