[FFmpeg-devel] [PATCH] libavformat/mxfdec.c: Recognize and Ignore MXF fill boxes

[martin schitter]

On 12.09.24 13:14, Nicolas Gaullier wrote:
> The message "Recognize and Ignore" does not make it clear what issue or grave defect is solved here.
> I see in the code that fill items are currently recognized as dark metadata and ignored likewise, but I don't see any issue here.
> Maybe could you comment a little bit about your intent ?

While developing this DNxUncompressed code I always got lots of this 
"Dark key ..." log messages in the debug output. This kind of output 
wouldn't be a surprise, if the key belongs to some rare and utterly 
irrelevant data box. but in this particular case the key stands for 
empty "fill" blocks, which are frequently used in various places in MXF 
files. They are an elementary building block of this container format.

On the muxer side of ffmpegs MXF code 'fill' is known and used in many 
places, but the demuxer doesn't recognize this element and just always 
prints these warnings about something "unknown". That's highly 
irritating and also inefficient, because 'fill' is used quite frequently 
e.g. as place holder to align frame data on 256byte boundaries etc.

It's really trivial to fix and I don't see, why we should debate any 
longer about this obvious flaw instead of just quickly solving the issue.

But if you want, you can rewrite the wording to "Recognize 'fill' in MXF 
data and suppress output" or whatever you like...

martin