[FFmpeg-devel] [PATCH v2] movenc: Use first H264/HEVC frame as extradata, if it is missing

[Michael Niedermayer]

On Wed, May 20, 2020 at 09:10:21AM +0300, Martin Storsjö wrote:
> Sticking a full frame in the extradata works, as the code for writing
> the avcC/hvcC extracts the relevant parameter set NAL units - provided
> that they actually exist in the frame.
> 
> Some encoders don't provide split out extradata directly on init (or
> at all). In particular, the MediaFoundation encoder wrapper doesn't
> always (depending on the actual encoder device) - this is the case for
> Qualcomm's HEVC encoder on SD835, and also on some QSV H264 encoders).
> 
> This only works for cases where the moov hasn't already been written
> (e.g. when not writing fragmented mp4 with empty_moov, unless using
> the delay_moov option).
> 
> Signed-off-by: Martin Storsjö <martin at martin.st>
> ---
>  libavformat/movenc.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index 27d7621e27..6a85440a3f 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -5584,7 +5584,9 @@ int ff_mov_write_packet(AVFormatContext *s, AVPacket *pkt)
>  
>      if ((par->codec_id == AV_CODEC_ID_DNXHD ||
>           par->codec_id == AV_CODEC_ID_TRUEHD ||
> -         par->codec_id == AV_CODEC_ID_AC3) && !trk->vos_len) {
> +         par->codec_id == AV_CODEC_ID_AC3 ||
> +         par->codec_id == AV_CODEC_ID_H264 ||
> +         par->codec_id == AV_CODEC_ID_HEVC) && !trk->vos_len) {
>          /* copy frame to create needed atoms */
>          trk->vos_len  = size;
>          trk->vos_data = av_malloc(size + AV_INPUT_BUFFER_PADDING_SIZE);

This changes avcintra output

example testcase:
./ffmpeg  -i ~/videos/mm-short.mpg -avcintra-class 100 -tune psnr -flags +ildct-global_header -t 0.5 -pix_fmt yuv422p10 -vf scale=1920:1080 -an file.mov


thx

[...]

-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

Avoid a single point of failure, be that a person or equipment.
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