[MEncoder-users] Color Space Problem with a Sequence of RGB JPEG Images

[Irv Elshoff]

Greeting,

I'm fairly new to Mencoder and would like to create movies from a 
sequence of existing JPEG files.  The final output is intended to be 
viewed by mainstream movie players such as MPlayer, QuickTime and 
Windows Media Player.  I'm not targeting any specific "hard" output 
media (e.g., DVD).

My problem is that the perceived colors in my input files - which look 
OK using every image viewer I know - are changed on output to something 
that does not look OK.  For instance, pure white (0xFFFFFF) becomes pink 
(0xFF7DFF) and pure black becomes olive green (0x008700) in the output.  
I'm looking for command-line options to maintain the perceived colors.

The JPEG images were produced by my own  C++ program using the 
ubiquitous libjpeg "6b" library.  In my output routine I set the color 
space to JCS_RGB because we need to retain as much information as 
possible (the source and most destinations are RGB-based).  If I change 
this to JCS_YCbCr  ("YUV") in a test program, Mencoder makes proper 
looking output, but this is not an option...

My second problem is that I have more than 2 TB of existing RGB JPEG 
files that I want to be able to process.  I can use something like 
ImageMagick to convert each frame to something else (e.g., uncompressed 
TIFF) and then make a movie from those files, but this isn't practical.

ImageMagick seems to know how to deal with RGB JPEGs.  I'm hoping that 
Mencoder can too, with the right command-line options.  I've tried a 
bunch based on what I read from Google hits, but nothing is working for me.

I'd really appreciate any help you can give.

If needed, I can supply a simple (single source file, GNU) C++ program 
to generate the synthetic test images, the test images themselves, 
single-frame mencoded movies (that demonstrate the problem), and 
whatever else is relevant.

For the record, the mencoder command line I'm using is:

    /opt/mplayer/bin/mencoder \
        mf://input.jpg \
        -mf fps=5  \
        -ovc lavc \
        -lavcopts vcodec=mpeg4:mbd=2:trell \
        -of lavf \
        -lavfopts format=mov \
        -o output.mov

      

I work on Linux and Mac.  I've got Windows XP if needed.

Cheers,
    Irv.