[FFmpeg-devel] [PATCH 1/3] avformat/dvdvideodec: add CLUT utilities and subtitle palette support

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Thu Mar 7 12:36:59 EET 2024


Anton Khirnov:
> Quoting Marth64 (2024-03-06 16:36:32)
>> Good morning,
>>
>> DVD subtitle palettes, which are natively YUV, are currently carried as
>> a hex string in their respective subtitle streams and have
>> no concept of colorspace tagging (even predating dvd demuxer). The
>> convention is to convert
>> them to RGB prior to storage. Common players will only render
>> the palettes properly if they are stored as RGB. Even ffmpeg itself
>> expects this, and already does -in libavformat- the YUV-RGB conversions,
>> specifically in mov.c and movenc.c.
>>
>> The point of this patch is to provide a consolidation of the code
>> that deals with creating the extradata as well as the RGB conversion.
>> That can then (1) enable usable palette support for DVD demuxer if it is
>> merged
>> and (2) start the process of consolidating the related conversions in
>> MOV muxer/demuxer and eventually find a way to properly tag
>> the colorspace.
> 
> Is there any reason ever to export YUV palette? Should this even be an
> option?
> 

Is the conversion lossless?

- Andreas



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