iff: support transparency

[ami_stuff]

C:\>ffmpeg -i DpaintTitle.brush
ffmpeg version N-35295-gb55dd10, Copyright (c) 2000-2011 the FFmpeg developers
  built on Nov 30 2011 00:52:52 with gcc 4.6.2
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-ru
ntime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libope
ncore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --en
able-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger -
-enable-libspeex --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwben
c --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-
libxvid --enable-zlib
  libavutil    51. 29. 1 / 51. 29. 1
  libavcodec   53. 39. 1 / 53. 39. 1
  libavformat  53. 22. 0 / 53. 22. 0
  libavdevice  53.  4. 0 / 53.  4. 0
  libavfilter   2. 50. 0 /  2. 50. 0
  libswscale    2.  1. 0 /  2.  1. 0
  libpostproc  51.  2. 0 / 51.  2. 0
[iff_byterun1 @ 020B90E0] Transparency not supported
    Last message repeated 1 times
[IFF @ 020B2320] Estimating duration from bitrate, this may be inaccurate
Input #0, IFF, from 'DpaintTitle.brush':
  Metadata:
    title           : DPaint 5 Title
    artist          : Geoffrey Rantala
    copyright       : 1994, Electronic Arts
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: iff_byterun1 (ILBM / 0x4D424C49), pal8, 275x84, SAR 44:5
2 DAR 3025:1092, 90k tbr, 90k tbn, 90k tbc
At least one output file must be specified

C:\>ffmpeg -i 1.lbm
ffmpeg version N-35295-gb55dd10, Copyright (c) 2000-2011 the FFmpeg developers
  built on Nov 30 2011 00:52:52 with gcc 4.6.2
  configuration: --enable-gpl --enable-version3 --disable-w32threads --enable-ru
ntime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libope
ncore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enable-libgsm --en
able-libmp3lame --enable-libopenjpeg --enable-librtmp --enable-libschroedinger -
-enable-libspeex --enable-libtheora --enable-libvo-aacenc --enable-libvo-amrwben
c --enable-libvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-
libxvid --enable-zlib
  libavutil    51. 29. 1 / 51. 29. 1
  libavcodec   53. 39. 1 / 53. 39. 1
  libavformat  53. 22. 0 / 53. 22. 0
  libavdevice  53.  4. 0 / 53.  4. 0
  libavfilter   2. 50. 0 /  2. 50. 0
  libswscale    2.  1. 0 /  2.  1. 0
  libpostproc  51.  2. 0 / 51.  2. 0
[iff_ilbm @ 020B90E0] Transparency not supported
    Last message repeated 1 times
[IFF @ 020B2320] Estimating duration from bitrate, this may be inaccurate
Input #0, IFF, from '1.lbm':
  Duration: N/A, bitrate: N/A
    Stream #0:0: Video: iff_ilbm (PBM  / 0x204D4250), pal8, 21x21, SAR 5:6 DAR 5
:6, 90k tbr, 90k tbn, 90k tbc
At least one output file must be specified

[Carl Eugen Hoyos]

Patch attached.

[ami_stuff]

The attached patch seems to work correctly with "DpaintTitle.brush" file, hoever it fails with iff ilbm files which I created with different background colors selected as transparent.

maybe this info will be useful:

​http://home.comcast.net/~erniew/lwsdk/docs/filefmts/ilbm.html

[Carl Eugen Hoyos]

Works fine here with my patch:
ffmpeg -i brown.brush -pix_fmt rgb32 out.png
(out.png has transparent background)

[ami_stuff]

Right, it works with -pix_fmt rgb32. I tested without it and only "dpainttitle.brush" converted with transparency.

ffmpeg -i *.brush out.png

[Carl Eugen Hoyos]

I fixed ffmpeg -i brown.brush out.png earlier today (unrelated to iff).

Please try to always add a failing command line (ffmpeg -i brown.brush out.png) and complete, uncut output, it makes understanding a problem much easier.

[ami_stuff]

if (s->masking & !MASK_HAS_TRANSPARENT_COLOR != MASK_NONE) { 
av_log(avctx, AV_LOG_ERROR, "Masking not supported\n"); 
return AVERROR_PATCHWELCOME; 
} 

This check seems to fail (allow decoding) file from ticket #705, so maybe something like this:

if (s->masking && s->masking != MASK_HAS_TRANSPARENT_COLOR) {
av_log(avctx, AV_LOG_ERROR, "Masking not supported\n");
return AVERROR_PATCHWELCOME;
}

Also I have created HAM8 file with transparency (and this seems to set automaticly masking as well), but maybe it would be ok to apply this patch and experiment with HAM8 sample when masking will be supported?

[Carl Eugen Hoyos]

Thank you for testing and suggesting a fix, new patch attached!

[ami_stuff]

the new check is ok

[ami_stuff]

please apply this patch