[FFmpeg-devel] [PATCH] avformat/movenc: allow ISMV timescale to be user-set

[Gyan]

On 23-01-2020 05:56 pm, Gyan Doshi wrote:
> As per the PIFF standard, the timescale of 10000000
> is recommended but not mandatory, so don't override
> the user-set value.
>
> A warning is shown for non-recommended values.
> ---
>   libavformat/movenc.c | 14 ++++++++++----
>   1 file changed, 10 insertions(+), 4 deletions(-)
>
> diff --git a/libavformat/movenc.c b/libavformat/movenc.c
> index fb44ee2c71..5bf434c325 100644
> --- a/libavformat/movenc.c
> +++ b/libavformat/movenc.c
> @@ -6389,6 +6389,8 @@ static int mov_init(AVFormatContext *s)
>               }
>               if (mov->video_track_timescale) {
>                   track->timescale = mov->video_track_timescale;
> +                if (mov->mode == MODE_ISM && mov->video_track_timescale != 10000000)
> +                    av_log(s, AV_LOG_WARNING, "Warning: some tools, like mp4split, assume a timescale of 10000000 for ISMV.\n");
>               } else {
>                   track->timescale = st->time_base.den;
>                   while(track->timescale < 10000)
> @@ -6486,10 +6488,14 @@ static int mov_init(AVFormatContext *s)
>           }
>           if (!track->height)
>               track->height = st->codecpar->height;
> -        /* The ism specific timescale isn't mandatory, but is assumed by
> -         * some tools, such as mp4split. */
> -        if (mov->mode == MODE_ISM)
> -            track->timescale = 10000000;
> +        /* The Protected Interoperable File Format (PIFF) standard, used by ISMV recommends but
> +           doesn't mandate a track timescale of 10,000,000. The muxer allows a custom timescale
> +           for video tracks, so if user-set, it isn't overwritten */
> +        if (mov->mode == MODE_ISM &&
> +            (st->codecpar->codec_type != AVMEDIA_TYPE_VIDEO ||
> +            (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO && !mov->video_track_timescale))) {
> +             track->timescale = 10000000;
> +        }
>   
>           avpriv_set_pts_info(st, 64, 1, track->timescale);
>   

Will push tonight.

Gyan