[FFmpeg-devel] [PATCHv2] avcodec/utils: do not reallocate packet buffer for AV_CODEC_ID_WRAPPED_AVFRAME

[wm4]

On Sun, 19 Feb 2017 14:35:42 +0100
Marton Balint <cus at passwd.hu> wrote:

> Reallocating a wrapped avframe invalidates internal pointers, such as extended
> data.
> 
> FFmpeg has another way of passing AVFrames to muxers, but it seems the API
> (av_write_uncoded_frame) is not implemented in the ffmpeg CLI yet.
> 
> Signed-off-by: Marton Balint <cus at passwd.hu>
> ---
>  libavcodec/utils.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> index f4085bf..184821a 100644
> --- a/libavcodec/utils.c
> +++ b/libavcodec/utils.c
> @@ -1820,7 +1820,7 @@ int attribute_align_arg avcodec_encode_audio2(AVCodecContext *avctx,
>      AVFrame *padded_frame = NULL;
>      int ret;
>      AVPacket user_pkt = *avpkt;
> -    int needs_realloc = !user_pkt.data;
> +    int needs_realloc = !user_pkt.data && avctx->codec_id != AV_CODEC_ID_WRAPPED_AVFRAME;
>  
>      *got_packet_ptr = 0;
>  
> @@ -1964,7 +1964,7 @@ int attribute_align_arg avcodec_encode_video2(AVCodecContext *avctx,
>  {
>      int ret;
>      AVPacket user_pkt = *avpkt;
> -    int needs_realloc = !user_pkt.data;
> +    int needs_realloc = !user_pkt.data && avctx->codec_id != AV_CODEC_ID_WRAPPED_AVFRAME;
>  
>      *got_packet_ptr = 0;
>  

I don't understand this logic in the first place. If nothing was
encoded (!ret), and avpkt->data is set (why is it set?), then the
AVPacket.buf is realllocated (why?) to the packet size (why???) - how
does it make sense?