[FFmpeg-devel] [PATCH] avformat/hls: fix seek accuracy problem

[Steven Liu]

2018-01-02 18:28 GMT+08:00  <mymoeyard at gmail.com>:
> From: Wu Zhiqiang <mymoeyard at gmail.com>
>
> HLS demuxer seeking use dts instead of pts.
> Demuxer skip some frame when dts is before pts in special case.
> And it is impossible to re-seek back to start time after playing.
> ---
>  libavformat/hls.c | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
>
> diff --git a/libavformat/hls.c b/libavformat/hls.c
> index 950cc4c3bd..069e7b06e9 100644
> --- a/libavformat/hls.c
> +++ b/libavformat/hls.c
> @@ -2086,6 +2086,7 @@ static int hls_read_packet(AVFormatContext *s, AVPacket *pkt)
>           * stream */
>          if (pls->needed && !pls->pkt.data) {
>              while (1) {
> +                int64_t pkt_ts;
>                  int64_t ts_diff;
>                  AVRational tb;
>                  ret = av_read_frame(pls->ctx, &pls->pkt);
> @@ -2101,9 +2102,17 @@ static int hls_read_packet(AVFormatContext *s, AVPacket *pkt)
>                          fill_timing_for_id3_timestamped_stream(pls);
>                      }
>
> +                    if (pls->pkt.pts != AV_NOPTS_VALUE)
> +                        pkt_ts =  pls->pkt.pts;
> +                    else if (pls->pkt.dts != AV_NOPTS_VALUE)
> +                        pkt_ts =  pls->pkt.dts;
> +                    else
> +                        pkt_ts = AV_NOPTS_VALUE;
> +
> +
>                      if (c->first_timestamp == AV_NOPTS_VALUE &&
> -                        pls->pkt.dts       != AV_NOPTS_VALUE)
> -                        c->first_timestamp = av_rescale_q(pls->pkt.dts,
> +                        pkt_ts       != AV_NOPTS_VALUE)
> +                        c->first_timestamp = av_rescale_q(pkt_ts,
>                              get_timebase(pls), AV_TIME_BASE_Q);
>                  }
>
> @@ -2113,15 +2122,16 @@ static int hls_read_packet(AVFormatContext *s, AVPacket *pkt)
>                  if (pls->seek_stream_index < 0 ||
>                      pls->seek_stream_index == pls->pkt.stream_index) {
>
> -                    if (pls->pkt.dts == AV_NOPTS_VALUE) {
> +                    if (pkt_ts == AV_NOPTS_VALUE) {
>                          pls->seek_timestamp = AV_NOPTS_VALUE;
>                          break;
>                      }
>
>                      tb = get_timebase(pls);
> -                    ts_diff = av_rescale_rnd(pls->pkt.dts, AV_TIME_BASE,
> +                    ts_diff = av_rescale_rnd(pkt_ts, AV_TIME_BASE,
>                                              tb.den, AV_ROUND_DOWN) -
>                              pls->seek_timestamp;
> +
>                      if (ts_diff >= 0 && (pls->seek_flags  & AVSEEK_FLAG_ANY ||
>                                          pls->pkt.flags & AV_PKT_FLAG_KEY)) {
>                          pls->seek_timestamp = AV_NOPTS_VALUE;
> --
> 2.15.0
>


LGTM , This patch can fix ticket : https://trac.ffmpeg.org/ticket/6850


Thanks

Steven