On date Tuesday 2024-07-02 01:41:31 -0500, Marth64 wrote:
> When -trim option is used (by default), padding cells
> at the beginning of the title are supposed to be ignored.
> The current implementation does the ignoring after we
> have locked on to the PGC navigation event stream,
> but does not set the PGC/PG state properly.
>
> This causes false positives and errors on some discs
> due to a search for a program stream cell that
> never succeeds. User would have to know to disable
> the -trim option to work around the issue.
>
> Simplify the logic and move it to the NAV packet
> event handling, in turn implementing the behaviour
> correctly and fixing the trim function for impacted discs.
>
> Signed-off-by: Marth64 <mart...@proxyid.net>
> ---
> libavformat/dvdvideodec.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/libavformat/dvdvideodec.c b/libavformat/dvdvideodec.c
> index e7132725b7..c694e8d00f 100644
> --- a/libavformat/dvdvideodec.c
> +++ b/libavformat/dvdvideodec.c
> @@ -624,7 +624,6 @@ static int dvdvideo_play_next_ps_block(AVFormatContext
> *s, DVDVideoPlaybackState
> dvdnav_vts_change_event_t *e_vts;
> dvdnav_cell_change_event_t *e_cell;
> int cur_title, cur_pgcn, cur_pgn, cur_angle, cur_title_unused, cur_ptt,
> cur_nb_angles;
> - int is_cell_promising = 0;
> pci_t *e_pci;
> dsi_t *e_dsi;
>
> @@ -706,23 +705,17 @@ static int dvdvideo_play_next_ps_block(AVFormatContext
> *s, DVDVideoPlaybackState
> continue;
>
> e_cell = (dvdnav_cell_change_event_t *) nav_buf;
> - is_cell_promising = !c->opt_trim ||
> dvdvideo_is_cell_promising(s, state->pgc, e_cell->cellN);
>
> - av_log(s, AV_LOG_DEBUG, "new cell: prev=%d new=%d
> promising=%d\n",
> - state->celln, e_cell->cellN,
> is_cell_promising);
> + av_log(s, AV_LOG_DEBUG, "new cell: prev=%d new=%d\n",
> state->celln, e_cell->cellN);
>
> if (!state->in_ps && !state->in_pgc) {
> if (cur_title == c->opt_title &&
> (c->opt_pgc || cur_ptt == c->opt_chapter_start) &&
> cur_pgcn == state->pgcn &&
> - cur_pgn == state->entry_pgn &&
> - is_cell_promising) {
> + cur_pgn == state->entry_pgn) {
>
> state->in_pgc = 1;
> }
> -
> - if (c->opt_trim && !is_cell_promising)
> - av_log(s, AV_LOG_INFO, "Skipping padding cell
> #%d\n", e_cell->cellN);
> } else if (state->celln >= e_cell->cellN || state->pgn >
> cur_pgn) {
> return AVERROR_EOF;
> }
> @@ -766,6 +759,13 @@ static int dvdvideo_play_next_ps_block(AVFormatContext
> *s, DVDVideoPlaybackState
> e_pci->pci_gi.nv_pck_lbn, state->vobu_duration,
> state->nav_pts);
>
> if (!state->in_ps) {
> + if (c->opt_trim && !dvdvideo_is_cell_promising(s,
> state->pgc, state->celln)) {
> + av_log(s, AV_LOG_INFO, "Skipping padding cell
> #%d\n", state->celln);
nit++: possibly add some more information to aid debugging, such as
"Trimming enabled, skipping padding cell for non promising cell ..."
[...]
Looks good to me anyway, thanks.
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