[FFmpeg-user] png, pipe, image2pipe

A BC miaou.pbl at gmail.com
Thu Mar 22 15:04:28 CET 2012


I searched on the list and found helpful information about what I want to
do but I can't make it work.
I try to pipe into ffmpeg a quantity of png files. I am working on making
it work with a simple example.

So, what I would do with a single file "Anim0001.png" is :
 ffmpeg -y -f image2 -i Anim0001.png -vcodec libx264 -filter pad=1080:814
wich works fine and make a single frame video.

To do it with a pipe :
 cat Anim0001.png | ffmpeg -y -f image2pipe -i - -vcodec libx264 -filter
pad=1080:814 Anim1.mkv
wich does not work (classic "Could not find codec parameter (Video: none)

So I put a "-vcodec png" before "-i -":
 cat Anim0001.png | ffmpeg -y -f image2pipe -vcodec png -i - -vcodec
libx264 -filter pad=1080:814 Anim1.mkv
wich fails (output below).

So I thought, maybe "-vcodec png" does not work correctly, and I tried to
do the first one again, with -vcodec png:
 ffmpeg -y -f image2 -vcodec png -i Anim0001.png -vcodec libx264 -filter
pad=1080:814 Anim1.mkv
which works fine too !

(I use the padding because my image is 1080x813 so I round for x264)

Here's what does not work :
cat Anim0001.png | ffmpeg -y -f image2pipe -vcodec png -i - -vcodec libx264
-filter pad="1080:814" Anim1.slow.mkv

And the stderr :
ffmpeg version git-2012-03-22-eb98412 Copyright (c) 2000-2012 the FFmpeg
  built on Mar 22 2012 12:45:00 with gcc 4.4.3
  configuration: --enable-gpl --enable-libfaac --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libtheora --enable-libvorbis
--enable-libx264 --enable-nonfree --enable-version3 --enable-x11grab
  libavutil      51. 44.100 / 51. 44.100
  libavcodec     54. 12.100 / 54. 12.100
  libavformat    54.  2.100 / 54.  2.100
  libavdevice    53.  4.100 / 53.  4.100
  libavfilter     2. 65.102 /  2. 65.102
  libswscale      2.  1.100 /  2.  1.100
  libswresample   0.  7.100 /  0.  7.100
  libpostproc    52.  0.100 / 52.  0.100
[png @ 0xa1792a0] chunk too big
[png @ 0xa1792a0] Missing png signature
    Last message repeated 13 times
[image2pipe @ 0xa16ab60] decoding for stream 0 failed
[image2pipe @ 0xa16ab60] Could not find codec parameters (Video: png)
[image2pipe @ 0xa16ab60] Estimating duration from bitrate, this may be
pipe:: could not find codec parameters

For information, I used this page to compile ffmpeg (I work on Ubuntu 10.04)

Do you know how I can make it work ?

Thanks for your help !

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