[FFmpeg-devel] [PATCH] avformat/mov: avoid seeking back to 0 on HEVC open GOP files

[FFmpeg-devel] [PATCH] avformat/mov: avoid seeking back to 0 on HEVC open GOP files

[llyyr]

ab77b878f1 attempted to fix the issue of broken packets being sent to
the decoder by implementing logic that kept attempting to PTS-step
backwards until it reached a valid point, however applying this
heuristic meant that in files that had no valid points (such as HEVC
videos shot on iPhones), we'd seek back to sample 0 on every seek
attempt. This meant that files that were previously seekable, albeit
with some skipped frames, were not seekable at all now.

Relax this heuristic a bit by giving up on seeking to a valid point if
we've tried a different sample and we still don't have a valid point to
seek to. This may some frames to be skipped on seeking but it's better
than not being able to seek at all in such files.

Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP files")
---
 libavformat/mov.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index 1996e0028c..60a4d581d9 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -9108,7 +9108,7 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
 {
     MOVStreamContext *sc = st->priv_data;
     FFStream *const sti = ffstream(st);
-    int sample, time_sample, ret;
+    int sample, time_sample, ret, next_ts, requested_sample;
     unsigned int i;
 
     // Here we consider timestamp to be PTS, hence try to offset it so that we
@@ -9129,7 +9129,17 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
 
         if (!sample || can_seek_to_key_sample(st, sample, timestamp))
             break;
-        timestamp -= FFMAX(sc->min_sample_duration, 1);
+
+        next_ts = timestamp - FFMAX(sc->min_sample_duration, 1);
+        requested_sample = av_index_search_timestamp(st, next_ts, flags);
+
+        // If we can't seek to the next pts either and it's a different sample,
+        // give up trying to find a good pts to seek to, otherwise we'll end up
+        // seeking back to sample 0 on every seek.
+        if (!can_seek_to_key_sample(st, requested_sample, next_ts) && sample != requested_sample)
+            break;
+
+        timestamp = next_ts;
     }
 
     mov_current_sample_set(sc, sample);
-- 
2.42.0

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Re: [FFmpeg-devel] [PATCH] avformat/mov: avoid seeking back to 0 on HEVC open GOP files

[llyyr]

On 9/23/23 16:40, llyyr wrote:
> ab77b878f1 attempted to fix the issue of broken packets being sent to
> the decoder by implementing logic that kept attempting to PTS-step
> backwards until it reached a valid point, however applying this
> heuristic meant that in files that had no valid points (such as HEVC
> videos shot on iPhones), we'd seek back to sample 0 on every seek
> attempt. This meant that files that were previously seekable, albeit
> with some skipped frames, were not seekable at all now.
> 
> Relax this heuristic a bit by giving up on seeking to a valid point if
> we've tried a different sample and we still don't have a valid point to
> seek to. This may some frames to be skipped on seeking but it's better
> than not being able to seek at all in such files.
> 
> Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP files")
> ---
>   libavformat/mov.c | 14 ++++++++++++--
>   1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index 1996e0028c..60a4d581d9 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -9108,7 +9108,7 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
>   {
>       MOVStreamContext *sc = st->priv_data;
>       FFStream *const sti = ffstream(st);
> -    int sample, time_sample, ret;
> +    int sample, time_sample, ret, next_ts, requested_sample;
>       unsigned int i;
>   
>       // Here we consider timestamp to be PTS, hence try to offset it so that we
> @@ -9129,7 +9129,17 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
>   
>           if (!sample || can_seek_to_key_sample(st, sample, timestamp))
>               break;
> -        timestamp -= FFMAX(sc->min_sample_duration, 1);
> +
> +        next_ts = timestamp - FFMAX(sc->min_sample_duration, 1);
> +        requested_sample = av_index_search_timestamp(st, next_ts, flags);
> +
> +        // If we can't seek to the next pts either and it's a different sample,
> +        // give up trying to find a good pts to seek to, otherwise we'll end up
> +        // seeking back to sample 0 on every seek.
> +        if (!can_seek_to_key_sample(st, requested_sample, next_ts) && sample != requested_sample)
> +            break;
> +
> +        timestamp = next_ts;
>       }
>   
>       mov_current_sample_set(sc, sample);

Pinging this as it seems to have been missed. The patch still applies on 
current master and the issue also still exists.
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

[FFmpeg-devel] [PATCH] avformat/mov: avoid seeking back to 0 on HEVC open GOP files

[llyyr.public]

From: llyyr <llyyr.public@gmail.com>

ab77b878f1 attempted to fix the issue of broken packets being sent to
the decoder by implementing logic that kept attempting to PTS-step
backwards until it reached a valid point, however applying this
heuristic meant that in files that had no valid points (such as HEVC
videos shot on iPhones), we'd seek back to sample 0 on every seek
attempt. This meant that files that were previously seekable, albeit
with some skipped frames, were not seekable at all now.

Relax this heuristic a bit by giving up on seeking to a valid point if
we've tried a different sample and we still don't have a valid point to
seek to. This may some frames to be skipped on seeking but it's better
than not being able to seek at all in such files.

Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP files")
Fixes: #10585
---
 libavformat/mov.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index b3fa748f27e8..6174a04c3169 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -10133,7 +10133,7 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
 {
     MOVStreamContext *sc = st->priv_data;
     FFStream *const sti = ffstream(st);
-    int sample, time_sample, ret;
+    int sample, time_sample, ret, next_ts, requested_sample;
     unsigned int i;
 
     // Here we consider timestamp to be PTS, hence try to offset it so that we
@@ -10154,7 +10154,17 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
 
         if (!sample || can_seek_to_key_sample(st, sample, timestamp))
             break;
-        timestamp -= FFMAX(sc->min_sample_duration, 1);
+
+        next_ts = timestamp - FFMAX(sc->min_sample_duration, 1);
+        requested_sample = av_index_search_timestamp(st, next_ts, flags);
+
+        // If we've reached a different sample trying to find a good pts to
+        // seek to, give up searching because we'll end up seeking back to
+        // sample 0 on every seek.
+        if (!can_seek_to_key_sample(st, requested_sample, next_ts) && sample != requested_sample)
+            break;
+
+        timestamp = next_ts;
     }
 
     mov_current_sample_set(sc, sample);
-- 
2.45.0

_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Re: [FFmpeg-devel] [PATCH] avformat/mov: avoid seeking back to 0 on HEVC open GOP files

[Philip Langdale via ffmpeg-devel]

On Wed, 15 May 2024 01:36:43 +0530
llyyr.public@gmail.com wrote:

> From: llyyr <llyyr.public@gmail.com>
> 
> ab77b878f1 attempted to fix the issue of broken packets being sent to
> the decoder by implementing logic that kept attempting to PTS-step
> backwards until it reached a valid point, however applying this
> heuristic meant that in files that had no valid points (such as HEVC
> videos shot on iPhones), we'd seek back to sample 0 on every seek
> attempt. This meant that files that were previously seekable, albeit
> with some skipped frames, were not seekable at all now.
> 
> Relax this heuristic a bit by giving up on seeking to a valid point if
> we've tried a different sample and we still don't have a valid point
> to seek to. This may some frames to be skipped on seeking but it's
> better than not being able to seek at all in such files.
> 
> Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP
> files") Fixes: #10585
> ---
>  libavformat/mov.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index b3fa748f27e8..6174a04c3169 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -10133,7 +10133,7 @@ static int mov_seek_stream(AVFormatContext
> *s, AVStream *st, int64_t timestamp, {
>      MOVStreamContext *sc = st->priv_data;
>      FFStream *const sti = ffstream(st);
> -    int sample, time_sample, ret;
> +    int sample, time_sample, ret, next_ts, requested_sample;
>      unsigned int i;
>  
>      // Here we consider timestamp to be PTS, hence try to offset it
> so that we @@ -10154,7 +10154,17 @@ static int
> mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp, 
>          if (!sample || can_seek_to_key_sample(st, sample, timestamp))
>              break;
> -        timestamp -= FFMAX(sc->min_sample_duration, 1);
> +
> +        next_ts = timestamp - FFMAX(sc->min_sample_duration, 1);
> +        requested_sample = av_index_search_timestamp(st, next_ts,
> flags); +
> +        // If we've reached a different sample trying to find a good
> pts to
> +        // seek to, give up searching because we'll end up seeking
> back to
> +        // sample 0 on every seek.
> +        if (!can_seek_to_key_sample(st, requested_sample, next_ts)
> && sample != requested_sample)
> +            break;
> +
> +        timestamp = next_ts;
>      }
>  
>      mov_current_sample_set(sc, sample);

LGTM.

I know it's been a _long time_ since you first sent this; I'll push next
week if there aren't any other comments.

--phil
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

Re: [FFmpeg-devel] [PATCH] avformat/mov: avoid seeking back to 0 on HEVC open GOP files

[Philip Langdale via ffmpeg-devel]

On Tue, 14 May 2024 19:07:59 -0700
Philip Langdale via ffmpeg-devel <ffmpeg-devel@ffmpeg.org> wrote:

> On Wed, 15 May 2024 01:36:43 +0530
> llyyr.public@gmail.com wrote:
> 
> > From: llyyr <llyyr.public@gmail.com>
> > 
> > ab77b878f1 attempted to fix the issue of broken packets being sent
> > to the decoder by implementing logic that kept attempting to
> > PTS-step backwards until it reached a valid point, however applying
> > this heuristic meant that in files that had no valid points (such
> > as HEVC videos shot on iPhones), we'd seek back to sample 0 on
> > every seek attempt. This meant that files that were previously
> > seekable, albeit with some skipped frames, were not seekable at all
> > now.
> > 
> > Relax this heuristic a bit by giving up on seeking to a valid point
> > if we've tried a different sample and we still don't have a valid
> > point to seek to. This may some frames to be skipped on seeking but
> > it's better than not being able to seek at all in such files.
> > 
> > Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP
> > files") Fixes: #10585
> 
> LGTM.
> 
> I know it's been a _long time_ since you first sent this; I'll push
> next week if there aren't any other comments.
> 

Pushed. Thanks!

--phil
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

[FFmpeg-devel] [PATCH] avformat/mov: avoid seeking back to 0 on HEVC open GOP files

[llyyr.public]

ab77b878f1 attempted to fix the issue of broken packets being sent to
the decoder by implementing logic that kept attempting to PTS-step
backwards until it reached a valid point, however applying this
heuristic meant that in files that had no valid points (such as HEVC
videos shot on iPhones), we'd seek back to sample 0 on every seek
attempt. This meant that files that were previously seekable, albeit
with some skipped frames, were not seekable at all now.

Relax this heuristic a bit by giving up on seeking to a valid point if
we've tried a different sample and we still don't have a valid point to
seek to. This may some frames to be skipped on seeking but it's better
than not being able to seek at all in such files.

Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP files")
Fixes: #10585
---
 libavformat/mov.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index b3fa748f27e8..6174a04c3169 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -10133,7 +10133,7 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
 {
     MOVStreamContext *sc = st->priv_data;
     FFStream *const sti = ffstream(st);
-    int sample, time_sample, ret;
+    int sample, time_sample, ret, next_ts, requested_sample;
     unsigned int i;
 
     // Here we consider timestamp to be PTS, hence try to offset it so that we
@@ -10154,7 +10154,17 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
 
         if (!sample || can_seek_to_key_sample(st, sample, timestamp))
             break;
-        timestamp -= FFMAX(sc->min_sample_duration, 1);
+
+        next_ts = timestamp - FFMAX(sc->min_sample_duration, 1);
+        requested_sample = av_index_search_timestamp(st, next_ts, flags);
+
+        // If we've reached a different sample trying to find a good pts to
+        // seek to, give up searching because we'll end up seeking back to
+        // sample 0 on every seek.
+        if (!can_seek_to_key_sample(st, requested_sample, next_ts) && sample != requested_sample)
+            break;
+
+        timestamp = next_ts;
     }
 
     mov_current_sample_set(sc, sample);

base-commit: b0093ab8a3d34bf2fefd6665464cc343a9ef0d53
-- 
2.45.0
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".

[FFmpeg-devel] [PATCH] avformat/mov: avoid seeking back to 0 on HEVC open GOP files

[llyyr.public]

ab77b878f1 attempted to fix the issue of broken packets being sent to
the decoder by implementing logic that kept attempting to PTS-step
backwards until it reached a valid point, however applying this
heuristic meant that in files that had no valid points (such as HEVC
videos shot on iPhones), we'd seek back to sample 0 on every seek
attempt. This meant that files that were previously seekable, albeit
with some skipped frames, were not seekable at all now.

Relax this heuristic a bit by giving up on seeking to a valid point if
we've tried a different sample and we still don't have a valid point to
seek to. This may some frames to be skipped on seeking but it's better
than not being able to seek at all in such files.

Fixes: ab77b878f1 ("avformat/mov: fix seeking with HEVC open GOP files")
Fixes: #10585
---
 libavformat/mov.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/libavformat/mov.c b/libavformat/mov.c
index b3fa748f27e8..6174a04c3169 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -10133,7 +10133,7 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
 {
     MOVStreamContext *sc = st->priv_data;
     FFStream *const sti = ffstream(st);
-    int sample, time_sample, ret;
+    int sample, time_sample, ret, next_ts, requested_sample;
     unsigned int i;
 
     // Here we consider timestamp to be PTS, hence try to offset it so that we
@@ -10154,7 +10154,17 @@ static int mov_seek_stream(AVFormatContext *s, AVStream *st, int64_t timestamp,
 
         if (!sample || can_seek_to_key_sample(st, sample, timestamp))
             break;
-        timestamp -= FFMAX(sc->min_sample_duration, 1);
+
+        next_ts = timestamp - FFMAX(sc->min_sample_duration, 1);
+        requested_sample = av_index_search_timestamp(st, next_ts, flags);
+
+        // If we've reached a different sample trying to find a good pts to
+        // seek to, give up searching because we'll end up seeking back to
+        // sample 0 on every seek.
+        if (!can_seek_to_key_sample(st, requested_sample, next_ts) && sample != requested_sample)
+            break;
+
+        timestamp = next_ts;
     }
 
     mov_current_sample_set(sc, sample);

base-commit: b0093ab8a3d34bf2fefd6665464cc343a9ef0d53
-- 
2.45.0
_______________________________________________
ffmpeg-devel mailing list
ffmpeg-devel@ffmpeg.org
https://ffmpeg.org/mailman/listinfo/ffmpeg-devel

To unsubscribe, visit link above, or email
ffmpeg-devel-request@ffmpeg.org with subject "unsubscribe".