[Libav-user] Does the image2 demuxer work with a custom AVIOContext?

[Robert Krüger]

On Wed, Feb 19, 2014 at 5:56 PM, Carl Eugen Hoyos <cehoyos at ag.or.at> wrote:
> Robert Krüger <krueger at ...> writes:
>
>> cat ~/samples/fate/dpx/lighthouse_rgb48.dpx | ./ffmpeg
>> -f image2pipe -vcodec dpx -i - ~/tmp/fromdpx_pipe2.png
>
>> [dpx  <at>  0x7fcb21822600] Overread buffer. Invalid header?
>
> The image is cut in the middle, I don't know if that is
> a problem with the parser or if it is a fundamental
> problem with image2pipe: Did you try very large pngs?

I just tested a png of 11MB and that worked ok except for the message
"pipe:: Input/output error" but I got that message also with dpx files
that worked.

Full CL and output:

ffmpeg version git-2014-01-19-8decf37 Copyright (c) 2000-2014 the
FFmpeg developers
  built on Jan 19 2014 15:49:12 with llvm-gcc 4.2.1 (LLVM build 2336.1.00)
  configuration: --enable-shared --disable-static --disable-doc
--disable-avdevice
--prefix=/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg/native/build/ffmpeg
--extra-cflags=-I/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg/native/build/libmp3lame/include/
--extra-ldflags=-L/Users/admin/repos/de.lesspain/de.lesspain.ffmpeg/native/build/libmp3lame/lib/
--extra-ldflags='-Wl,-rpath, at loader_path/../lib' --enable-libmp3lame
  libavutil      52. 62.100 / 52. 62.100
  libavcodec     55. 48.101 / 55. 48.101
  libavformat    55. 24.100 / 55. 24.100
  libavfilter     4.  1.100 /  4.  1.100
  libswscale      2.  5.101 /  2.  5.101
  libswresample   0. 17.104 /  0. 17.104
[image2pipe @ 0x101808200] Stream #0: not enough frames to estimate
rate; consider increasing probesize
Input #0, image2pipe, from 'pipe:':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: png, rgba64be, 1920x1080 [SAR 9:16 DAR 1:1],
25 tbr, 25 tbn, 25 tbc
Output #0, image2, to '/Users/krueger/tmp/frompng_pipe2.png':
  Metadata:
    encoder         : Lavf55.24.100
    Stream #0:0: Video: png, rgba64be, 1920x1080 [SAR 9:16 DAR 1:1],
q=2-31, 200 kb/s, 90k tbn, 25 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (png -> png)
pipe:: Input/output error
frame=    1 fps=0.9 q=0.0 Lsize=N/A time=00:00:00.04 bitrate=N/A
video:11038kB audio:0kB subtitle:0 global headers:0kB muxing overhead
-100.000195%

The output file looks ok. On a sidenote:  [SAR 9:16 DAR 1:1] does not
seem correct for a 1920:1080 file.