1bpp interlaced png (without filter) decodes incorrectly

[ami_stuff]

the file is png 1bpp interlaced without any filter, decodes incorrectly

C:\>ffmpeg -i "1bpp_interlaced_none.png"
ffmpeg version git-N-29961-g9763420, Copyright (c) 2000-2011 the FFmpeg develope
rs
  built on May 16 2011 18:13:11 with gcc 4.5.3
  configuration: --enable-gpl --enable-version3 --enable-memalign-hack --enable-
runtime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libo
pencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --
enable-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger
 --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libvpx --enabl
e-libx264 --enable-libxavs --enable-libxvid --enable-zlib --pkg-config=pkg-confi
g
  libavutil    51.  2. 1 / 51.  2. 1
  libavcodec   53.  5. 0 / 53.  5. 0
  libavformat  53.  1. 0 / 53.  1. 0
  libavdevice  53.  0. 0 / 53.  0. 0
  libavfilter   2.  5. 0 /  2.  5. 0
  libswscale    0. 14. 0 /  0. 14. 0
  libpostproc  51.  2. 0 / 51.  2. 0
Input #0, image2, from '1bpp_interlaced_none.png':
  Duration: 00:00:00.04, start: 0.000000, bitrate: N/A
    Stream #0.0: Video: png, monob, 1023x767, 25 tbr, 25 tbn, 25 tbc
At least one output file must be specified

[ami_stuff]

1bpp interlaced with paeth and sub filters also decodes incorrectly, but maybe fix of this ticket will fix them as well

[saste]

Hi,

that's really a libsdl ancient bug, libsdl is not able to cope with files with odd width.

I wonder how should we deal with it, if rescaling or failing. Best solution would be to report the bug upstream and get it hopefully fixed.

[ami_stuff]

There are two problems:

ffmpeg converts the file incorrectly

and

ffplay displays the file incorrectly (add black line) because of libsdl bug,

but the real problem here is that ffmpeg can't convert correctly png interlaced files.

[saste]

Replying to ami_stuff:

There are two problems:

ffmpeg converts the file incorrectly

and

ffplay displays the file incorrectly (add black line) because of libsdl bug,

but the real problem here is that ffmpeg can't convert correctly png interlaced files.

Indeed, I was misled by the libsdl bug, I confirm the bug.

A complete review of the png decoder would be nice, also for adding support of the missing features but I don't think I'll have time for this in the next future.

[michael]

Fixed locally will push soon