[FFmpeg-devel] [PATCH v2 2/4] avcodec/hevcdec: create AVFrame side data from HEVC timecodes like H.264

[Josh de Kock]

On 17/06/2020 17:07, lance.lmwang at gmail.com wrote:
> From: Limin Wang <lance.lmwang at gmail.com>
> 
> Signed-off-by: Limin Wang <lance.lmwang at gmail.com>
> ---
>   libavcodec/hevcdec.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
>   1 file changed, 44 insertions(+)
> 
> diff --git a/libavcodec/hevcdec.c b/libavcodec/hevcdec.c
> index c9e28f5..39abbb9 100644
> --- a/libavcodec/hevcdec.c
> +++ b/libavcodec/hevcdec.c
> @@ -2808,6 +2808,50 @@ static int set_side_data(HEVCContext *s)
>       }
>       s->sei.unregistered.nb_buf_ref = 0;
>   
> +    if (s->sei.timecode.present) {
> +        uint32_t tc = 0;
> +        uint32_t *tc_sd;
> +        AVFrameSideData *tcside = av_frame_new_side_data(out, AV_FRAME_DATA_S12M_TIMECODE,
> +                                                         sizeof(uint32_t) * 4);
> +        if (!tcside)
> +            return AVERROR(ENOMEM);
> +
> +        tc_sd = (uint32_t*)tcside->data;
> +        tc_sd[0] = s->sei.timecode.num_clock_ts;
> +
> +        for (int i = 0; i < tc_sd[0]; i++) {
> +            uint32_t frames;
> +
> +            /* For SMPTE 12-M timecodes, frame count is a special case if > 30 FPS.
> +               See SMPTE ST 12-1:2014 Sec 12.1 for more info. */
> +            if (av_cmp_q(s->avctx->framerate, (AVRational) {30, 1}) == 1) {
> +                frames = s->sei.timecode.n_frames[i] / 2;
> +                if (s->sei.timecode.n_frames[i] % 2 == 1) {
> +                    if (av_cmp_q(s->avctx->framerate, (AVRational) {50, 1}) == 0)
> +                        tc |= (1 << 7);
> +                    else
> +                        tc |= (1 << 23);
> +                }
> +            } else {
> +                frames = s->sei.timecode.n_frames[i];
> +            }
> +
> +            tc |= s->sei.timecode.cnt_dropped_flag[i] << 30;
> +            tc |= (frames / 10) << 28;
> +            tc |= (frames % 10) << 24;
> +            tc |= (s->sei.timecode.seconds_value[i] / 10) << 20;
> +            tc |= (s->sei.timecode.seconds_value[i] % 10) << 16;
> +            tc |= (s->sei.timecode.minutes_value[i] / 10) << 12;
> +            tc |= (s->sei.timecode.minutes_value[i] % 10) << 8;
> +            tc |= (s->sei.timecode.hours_value[i] / 10) << 4;
> +            tc |= (s->sei.timecode.hours_value[i] % 10);
> +
> +            tc_sd[i + 1] = tc;
> +        }
> +
> +        s->sei.timecode.num_clock_ts = 0;
> +    }
> +
>       return 0;
>   }
>   
> 

As you said in the commit message, h264 already does this so it would be 
nice if you didn't duplicate the code. Split both parts of s12m decoding 
you've copied into a common h2645 or just an s12m file maybe?

-- 
Josh