[FFmpeg-devel] [PATCH] avformat/movenc: Fix editlist with hybrid_fragmented

[Martin Storsjö]

On Fri, 13 Jun 2025, Zhao Zhili wrote:

> From: Zhao Zhili <zhilizhao at tencent.com>
>
> The segment_duration must not be set to zero when writing the moov
> atom for the second time. This is related to edit lists in standard
> MP4 files.
> ---
> libavformat/movenc.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index cd5b45f6fe..a651d6d618 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -4036,8 +4036,13 @@ static int mov_write_edts_tag(AVIOContext *pb, MOVMuxContext *mov,
>     /* For fragmented files, we don't know the full length yet. Setting
>      * duration to 0 allows us to only specify the offset, including
>      * the rest of the content (from all future fragments) without specifying
> -     * an explicit duration. */
> -    if (mov->flags & FF_MOV_FLAG_FRAGMENT)
> +     * an explicit duration.
> +     *
> +     * For hybrid_fragmented during mov_write_trailer (mov->moov_written != 0),
> +     * don't reset duration to zero.
> +     */
> +    if (mov->flags & FF_MOV_FLAG_FRAGMENT &&
> +        !(mov->flags & FF_MOV_FLAG_HYBRID_FRAGMENTED && mov->moov_written))
>         duration = 0;
>
>     /* duration */
> -- 
> 2.46.0

LGTM, this sounds reasonable to me.

// Martin