diff mbox series

[FFmpeg-devel,v4] avformat/dvdvideodec: Fix incorrect padding cell trim logic

Message ID 20240702064131.1310942-1-marth64@proxyid.net
State New
Headers show
Series [FFmpeg-devel,v4] avformat/dvdvideodec: Fix incorrect padding cell trim logic | expand

Checks

Context Check Description
yinshiyou/make_loongarch64 success Make finished
yinshiyou/make_fate_loongarch64 fail Make fate failed
andriy/make_x86 success Make finished
andriy/make_fate_x86 success Make fate finished

Commit Message

Marth64 July 2, 2024, 6:41 a.m. UTC
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 <marth64@proxyid.net>
---
 libavformat/dvdvideodec.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

Comments

Stefano Sabatini July 6, 2024, 11:18 a.m. UTC | #1
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 <marth64@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.
Marth64 July 6, 2024, 5:53 p.m. UTC | #2
>t++: possibly add some more information to aid debugging, such as
"Trimming enabled, skipping padding cell for non promising cell ..."

Thanks Stefano for the review. A further cleanup patch set is coming
shortly with a patch specifically on language in log messages, will include
this.

Cheers,
Marth64 July 12, 2024, 3:30 a.m. UTC | #3
Ping to apply on this set of 3, so I can send seeking and additional
cleanup set (as a collection). Thank you!
Stefano Sabatini July 13, 2024, 3:37 p.m. UTC | #4
On Fri, Jul 12, 2024 at 5:31 AM Marth64 <marth64@proxyid.net> wrote:
>
> Ping to apply on this set of 3, so I can send seeking and additional
> cleanup set (as a collection). Thank you!

Applied patches:
eb07a59 avformat/dvdvideodec: Don't add chapter markers for empty/dummy PTTs
f37f86a avformat/dvdvideodec: Remove redundant ret initializations
f1abb75 avformat/dvdvideodec: Fix incorrect padding cell trim logic

Thanks.
Marth64 July 13, 2024, 3:52 p.m. UTC | #5
Thank you!
diff mbox series

Patch

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);
+
+                        i = 0;
+                        continue;
+                    }
+
                     av_log(s, AV_LOG_DEBUG, "navigation: locked to program stream\n");
 
                     state->in_ps = 1;