[FFmpeg-user] Questions about readout important metadata from DPX files ("logarthmic/linear") and recreate DPX with same metadata

Christoph Gerstbauer christophgerstbauer at gmail.com
Mon Mar 9 14:45:05 CET 2015

> (This is not the first time that I am slightly
> surprised people use FFmpeg to prove that an
> encoder of FFmpeg is lossless.)
Do you have any ideas for proving the losslessness with other tools than 
>> The Original has LOGARITHMIC 10bit (RGB 10bit log)
> FFmpeg does not support logarithmic dpx
> afaict.
> If this is really a feature that would
> help you, it would be possible to force
> the "logarithmic" flag on encoding (but
> I am not convinced this is really useful).

It could be usefull because I save the metadata (which is not supported 
in AVI) seperatelly from the ffv1 avi and encode it back into the DPX 
when recreating it.
For this usecase I can use mediainfo to readout the "logarithmic" 
information and set a flag at ffmpeg when encoding new DPX files.

> (It is of course trivial to read the
> information from the file but I wonder
> how it would be useful given that FFmpeg
> doesn't know what to do with the
> information.)
> Consider to upload a sample (or post a
> gm command line).

Sample link:

Best Regards

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