[FFmpeg-devel] [PATCH 2/7] avformat/dvdvideodec: Implement seeking
Sean McGovern
gseanmcg at gmail.com
Sun Jul 28 18:20:41 EEST 2024
Hi Marth64,
On Sun, Jul 28, 2024 at 3:35 AM Marth64 <marth64 at proxyid.net> wrote:
>
> Player applications can now enjoy seeking while playing back
> a title. Accuracy is at the mercy of what libdvdnav offers,
> which is currently dvdnav_jump_to_sector_by_time().
>
> Signed-off-by: Marth64 <marth64 at proxyid.net>
> ---
> libavformat/dvdvideodec.c | 93 ++++++++++++++++++++++++++++++++++-----
> 1 file changed, 82 insertions(+), 11 deletions(-)
>
> diff --git a/libavformat/dvdvideodec.c b/libavformat/dvdvideodec.c
> index e745165e00..e8301b1173 100644
> --- a/libavformat/dvdvideodec.c
> +++ b/libavformat/dvdvideodec.c
> @@ -110,6 +110,7 @@ typedef struct DVDVideoPlaybackState {
> int in_pgc; /* if our navigator is in the PGC */
> int in_ps; /* if our navigator is in the program stream */
> int in_vts; /* if our navigator is in the VTS */
> + int is_seeking; /* relax navigation path while seeking */
> int64_t nav_pts; /* PTS according to IFO, not frame-accurate */
> uint64_t pgc_duration_est; /* estimated duration as reported by IFO */
> uint64_t pgc_elapsed; /* the elapsed time of the PGC, cell-relative */
> @@ -722,7 +723,8 @@ static int dvdvideo_play_next_ps_block(AVFormatContext *s, DVDVideoPlaybackState
>
> state->in_pgc = 1;
> }
> - } else if (state->celln >= e_cell->cellN || state->pgn > cur_pgn) {
> + } else if (!state->is_seeking &&
> + (state->celln >= e_cell->cellN || state->pgn > cur_pgn)) {
> return AVERROR_EOF;
> }
>
> @@ -735,7 +737,7 @@ static int dvdvideo_play_next_ps_block(AVFormatContext *s, DVDVideoPlaybackState
> if (!state->in_pgc)
> continue;
>
> - if ((state->ptt > 0 && state->ptt > cur_ptt) ||
> + if ((!state->is_seeking && state->ptt > 0 && state->ptt > cur_ptt) ||
> (c->opt_chapter_end > 0 && cur_ptt > c->opt_chapter_end)) {
> return AVERROR_EOF;
> }
> @@ -807,13 +809,15 @@ static int dvdvideo_play_next_ps_block(AVFormatContext *s, DVDVideoPlaybackState
> return AVERROR_INPUT_CHANGED;
> }
>
> - memcpy(buf, &nav_buf, nav_len);
> -
> if (state->pgn != cur_pgn)
> av_log(s, AV_LOG_WARNING, "Unexpected PG change (expected=%d actual=%d); "
> "this could be due to a missed NAV packet\n",
> state->pgn, cur_pgn);
>
> + memcpy(buf, &nav_buf, nav_len);
> +
> + state->is_seeking = 0;
> +
> return nav_len;
> case DVDNAV_WAIT:
> if (dvdnav_wait_skip(state->dvdnav) != DVDNAV_STATUS_OK) {
> @@ -1659,17 +1663,17 @@ static int dvdvideo_read_packet(AVFormatContext *s, AVPacket *pkt)
> }
>
> av_log(s, AV_LOG_TRACE, "st=%d pts=%" PRId64 " dts=%" PRId64 " "
> - "pts_offset=%" PRId64 " first_pts=%" PRId64 "\n",
> + "pts_offset=%" PRId64 " first_pts=%" PRId64 " is_seeking=%d\n",
> pkt->stream_index, pkt->pts, pkt->dts,
> - c->pts_offset);
> + c->pts_offset, c->first_pts, c->play_state.is_seeking);
>
> return 0;
>
> discard:
> av_log(s, AV_LOG_VERBOSE, "Discarding packet @ st=%d pts=%" PRId64 " dts=%" PRId64 " "
> - "st_matched=%d\n",
> + "st_matched=%d is_seeking=%d\n",
> st_matched ? pkt->stream_index : -1, pkt->pts, pkt->dts,
> - st_matched);
> + st_matched, c->play_state.is_seeking);
>
> return FFERROR_REDO;
> }
> @@ -1690,6 +1694,72 @@ static int dvdvideo_close(AVFormatContext *s)
> return 0;
> }
>
> +static int dvdvideo_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
> +{
> + DVDVideoDemuxContext *c = s->priv_data;
> + int ret;
> + int64_t new_nav_pts;
> + pci_t* new_nav_pci;
> + dsi_t* new_nav_dsi;
> +
> + if (c->opt_menu || c->opt_chapter_start > 1) {
> + av_log(s, AV_LOG_ERROR, "Seeking is not compatible with menus or chapter extraction\n");
> +
> + return AVERROR_PATCHWELCOME;
> + }
> +
> + if ((flags & AVSEEK_FLAG_BYTE))
> + return AVERROR(ENOSYS);
> +
> + if (timestamp < 0)
> + return AVERROR(EINVAL);
> +
> + if (!c->seek_warned) {
> + av_log(s, AV_LOG_WARNING, "Seeking is inherently unreliable and will result "
> + "in imprecise timecodes from this point\n");
> + c->seek_warned = 1;
> + }
> +
> + /* XXX(PATCHWELCOME): use dvdnav_jump_to_sector_by_time(c->play_state.dvdnav, timestamp, 0)
> + * when it is available in a released version of libdvdnav; it is more accurate */
> + if (dvdnav_time_search(c->play_state.dvdnav, timestamp) != DVDNAV_STATUS_OK) {
> + av_log(s, AV_LOG_ERROR, "libdvdnav: seeking to %" PRId64 " failed\n", timestamp);
> +
> + return AVERROR_EXTERNAL;
> + }
I think avpriv_report_missing_feature() might be more appropriate here.
Also, does this build properly if a user does not have libdvdnav?
> +
> + new_nav_pts = dvdnav_get_current_time (c->play_state.dvdnav);
> + new_nav_pci = dvdnav_get_current_nav_pci(c->play_state.dvdnav);
> + new_nav_dsi = dvdnav_get_current_nav_dsi(c->play_state.dvdnav);
> +
> + if (new_nav_pci == NULL || new_nav_dsi == NULL) {
> + av_log(s, AV_LOG_ERROR, "Invalid NAV packet after seeking\n");
> +
> + return AVERROR_INVALIDDATA;
> + }
> +
> + c->play_state.in_pgc = 1;
> + c->play_state.in_ps = 0;
> + c->play_state.is_seeking = 1;
> + c->play_state.nav_pts = timestamp;
> + c->play_state.ptm_offset = timestamp;
> + c->play_state.ptm_discont = 0;
> + c->play_state.vobu_e_ptm = new_nav_pci->pci_gi.vobu_s_ptm;
> +
> + c->first_pts = 0;
> + c->play_started = 0;
> + c->pts_offset = timestamp;
> + c->subdemux_reset = 0;
> +
> + if ((ret = dvdvideo_subdemux_reset(s)) < 0)
> + return ret;
> +
> + av_log(s, AV_LOG_DEBUG, "seeking: requested_nav_pts=%" PRId64 " new_nav_pts=%" PRId64 "\n",
> + timestamp, new_nav_pts);
> +
> + return 0;
> +}
> +
> #define OFFSET(x) offsetof(DVDVideoDemuxContext, x)
> static const AVOption dvdvideo_options[] = {
> {"angle", "playback angle number", OFFSET(opt_angle), AV_OPT_TYPE_INT, { .i64=1 }, 1, 9, AV_OPT_FLAG_DECODING_PARAM },
> @@ -1718,11 +1788,12 @@ const FFInputFormat ff_dvdvideo_demuxer = {
> .p.name = "dvdvideo",
> .p.long_name = NULL_IF_CONFIG_SMALL("DVD-Video"),
> .p.priv_class = &dvdvideo_class,
> - .p.flags = AVFMT_NOFILE | AVFMT_SHOW_IDS | AVFMT_TS_DISCONT |
> - AVFMT_NO_BYTE_SEEK | AVFMT_NOGENSEARCH | AVFMT_NOBINSEARCH,
> + .p.flags = AVFMT_SHOW_IDS | AVFMT_TS_DISCONT | AVFMT_SEEK_TO_PTS |
> + AVFMT_NOFILE | AVFMT_NO_BYTE_SEEK | AVFMT_NOGENSEARCH | AVFMT_NOBINSEARCH,
> .priv_data_size = sizeof(DVDVideoDemuxContext),
> .flags_internal = FF_INFMT_FLAG_INIT_CLEANUP,
> .read_close = dvdvideo_close,
> .read_header = dvdvideo_read_header,
> - .read_packet = dvdvideo_read_packet
> + .read_packet = dvdvideo_read_packet,
> + .read_seek = dvdvideo_read_seek
> };
> --
> 2.34.1
>
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-- Sean McGovern
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