[FFmpeg-devel] [PATCH] avformat/movenc: disallow buggy flags combination

[Martin Storsjö]

On Mon, 26 May 2025, Gyan Doshi wrote:

> Usage of hybrid_fragmented and faststart together can result in files with
> loss of sync and bitstream parsing errors upon playback.
> ---
> libavformat/movenc.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index 4bc8bd1b2a..9392ba5370 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -7731,6 +7731,12 @@ static int mov_init(AVFormatContext *s)
>                       FF_MOV_FLAG_FRAG_EVERY_FRAME))
>         mov->flags |= FF_MOV_FLAG_FRAGMENT;
>
> +    if (mov->flags & FF_MOV_FLAG_HYBRID_FRAGMENTED &&
> +        mov->flags & FF_MOV_FLAG_FASTSTART) {
> +        av_log(s, AV_LOG_ERROR, "Setting both hybrid_fragmented and faststart is not supported.\n");
> +        return AVERROR(EINVAL);
> +    }
> +

Ok

// Martin