[FFmpeg-devel] [PATCH v4 2/5] avformat: add av_program_copy()

[Anton Khirnov]

Quoting Gyan Doshi (2023-02-18 05:49:46)
> diff --git a/libavformat/avformat.h b/libavformat/avformat.h
> index 33ab0bc8ba..46b4d177c3 100644
> --- a/libavformat/avformat.h
> +++ b/libavformat/avformat.h
> @@ -1886,6 +1886,28 @@ uint8_t *av_stream_get_side_data(const AVStream *stream,
>  
>  AVProgram *av_new_program(AVFormatContext *s, int id);
>  
> +/**
> + * Copy an AVProgram from one AVFormatContext to another.
> + *
> + * Streams in the destination context whose IDs match the IDs of the streams in the
> + * source AVProgram index are added to the stream index of the copied AVProgram.
> + *
> + * If a new program has to be added, the function expects and requires any existing buffer
> + * holding the array of pointers to AVPrograms in the destination context to have its size
> + * be a power-of-two value. This should be the case if all earlier programs were created
> + * using av_new_program or this function. 
> + *
> + * @param dst           pointer to the target muxer context
> + * @param src           pointer to the source muxer context
> + * @param progid        ID of the program to be copied
> + * @param overwrite     whether to overwrite if target muxer already
> + *                      contains a program with the same ID
> + *
> + * @return  >= 0 in case of success, a negative AVERROR code in case of
> + *          failure
> + */
> +int av_program_copy(AVFormatContext *dst, const AVFormatContext *src, int progid, int overwrite);

Why identify source programs by id rather than the structure itself?

Also, overwrite should really be a more generic flags field for future
extension.

Overall I remain uneasy about this being public - the semantics are
rather tricky and fragile unless the streams between src and dst match
exactly.

-- 
Anton Khirnov