Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Wed, 6 Jan 2021, Matthieu Bouron wrote:
On Tue, Jan 05, 2021 at 09:56:39PM +0100, Marton Balint wrote:
On Tue, 5 Jan 2021, Matthieu Bouron wrote:
Could you factorize this to a function? It seems you are doing exactly the
same thing here and below.
New patch attached.
[...]
diff --git a/libavformat/mov.c b/libavformat/mov.c
index c6a2d9c388d..e6d0de38c6f 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -8122,6 +8122,15 @@ static int mov_seek_stream(AVFormatContext *s, AVStream
*st, int64_t timestamp,
return sample;
}
+static int64_t mov_get_skip_samples(AVStream *st, int64_t seek_ts)
+{
Maybe cleaner to make "sample" a parameter instead of seek_ts.
Done.
+MOVStreamContext *sc = st->priv_data;
+int64_t first_ts = st->internal->index_entries[0].timestamp;
+
+/* compute skip samples according to stream start_pad, seek ts and first
ts */
+return FFMAX(sc->start_pad - (seek_ts - first_ts), 0);
Are you sure you don't need any time base correction here? Difference of
timestamps is in stream time base, but skip_samples is the number of samples
is in 1/sample_rate time base...
Done.
Also you are setting skip_samples for all streams, shouldn't you restrict it
to audio only, so return 0 for non-audio streams?
I agree, it should only makes sense for audio streams. Updated.
+}
+
static int mov_read_seek(AVFormatContext *s, int stream_index, int64_t
sample_time, int flags)
{
MOVContext *mc = s->priv_data;
@@ -8140,18 +8149,21 @@ static int mov_read_seek(AVFormatContext *s, int
stream_index, int64_t sample_ti
if (mc->seek_individually) {
/* adjust seek timestamp to found sample timestamp */
int64_t seek_timestamp = st->internal->index_entries[sample].timestamp;
+st->internal->skip_samples = mov_get_skip_samples(st, seek_timestamp);
for (i = 0; i < s->nb_streams; i++) {
int64_t timestamp;
-MOVStreamContext *sc = s->streams[i]->priv_data;
st = s->streams[i];
-st->internal->skip_samples = (sample_time <= 0) ? sc->start_pad :
0;
if (stream_index == i)
continue;
timestamp = av_rescale_q(seek_timestamp,
s->streams[stream_index]->time_base, st->time_base);
-mov_seek_stream(s, st, timestamp, flags);
+sample = mov_seek_stream(s, st, timestamp, flags);
+if (sample >= 0) {
+seek_timestamp = st->internal->index_entries[sample].timestamp;
This is destorying seek_timestamp, which seems unintended.
It was unintended. Fixed.
+st->internal->skip_samples = mov_get_skip_samples(st,
seek_timestamp);
+}
New patch attached.
Thanks, applied.
Regards,
Marton
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Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Tue, Jan 05, 2021 at 09:56:39PM +0100, Marton Balint wrote:
>
> On Tue, 5 Jan 2021, Matthieu Bouron wrote:
>
> > > Could you factorize this to a function? It seems you are doing exactly the
> > > same thing here and below.
> >
> > New patch attached.
>
> [...]
>
> > diff --git a/libavformat/mov.c b/libavformat/mov.c
> > index c6a2d9c388d..e6d0de38c6f 100644
> > --- a/libavformat/mov.c
> > +++ b/libavformat/mov.c
> > @@ -8122,6 +8122,15 @@ static int mov_seek_stream(AVFormatContext *s,
> > AVStream *st, int64_t timestamp,
> > return sample;
> > }
> >
> > +static int64_t mov_get_skip_samples(AVStream *st, int64_t seek_ts)
> > +{
>
> Maybe cleaner to make "sample" a parameter instead of seek_ts.
Done.
>
> > +MOVStreamContext *sc = st->priv_data;
> > +int64_t first_ts = st->internal->index_entries[0].timestamp;
> > +
> > +/* compute skip samples according to stream start_pad, seek ts and
> > first ts */
> > +return FFMAX(sc->start_pad - (seek_ts - first_ts), 0);
>
> Are you sure you don't need any time base correction here? Difference of
> timestamps is in stream time base, but skip_samples is the number of samples
> is in 1/sample_rate time base...
Done.
>
> Also you are setting skip_samples for all streams, shouldn't you restrict it
> to audio only, so return 0 for non-audio streams?
I agree, it should only makes sense for audio streams. Updated.
>
> > +}
> > +
> > static int mov_read_seek(AVFormatContext *s, int stream_index, int64_t
> > sample_time, int flags)
> > {
> > MOVContext *mc = s->priv_data;
> > @@ -8140,18 +8149,21 @@ static int mov_read_seek(AVFormatContext *s, int
> > stream_index, int64_t sample_ti
> > if (mc->seek_individually) {
> > /* adjust seek timestamp to found sample timestamp */
> > int64_t seek_timestamp =
> > st->internal->index_entries[sample].timestamp;
> > +st->internal->skip_samples = mov_get_skip_samples(st,
> > seek_timestamp);
> >
> > for (i = 0; i < s->nb_streams; i++) {
> > int64_t timestamp;
> > -MOVStreamContext *sc = s->streams[i]->priv_data;
> > st = s->streams[i];
> > -st->internal->skip_samples = (sample_time <= 0) ?
> > sc->start_pad : 0;
> >
> > if (stream_index == i)
> > continue;
> >
> > timestamp = av_rescale_q(seek_timestamp,
> > s->streams[stream_index]->time_base, st->time_base);
> > -mov_seek_stream(s, st, timestamp, flags);
> > +sample = mov_seek_stream(s, st, timestamp, flags);
> > +if (sample >= 0) {
> > +seek_timestamp =
> > st->internal->index_entries[sample].timestamp;
>
> This is destorying seek_timestamp, which seems unintended.
It was unintended. Fixed.
>
> > +st->internal->skip_samples = mov_get_skip_samples(st,
> > seek_timestamp);
> > +}
New patch attached.
[...]
--
Matthieu B.
>From 82ed68085304ef98215bc1189d09f85c7c70fc0c Mon Sep 17 00:00:00 2001
From: Matthieu Bouron
Date: Fri, 30 Oct 2020 15:38:51 +0100
Subject: [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
Currently skip_samples is set to start_pad if sample_time is lesser or
equal to 0. This can cause issues if the stream starts with packets that
have negative pts. Calling avformat_seek_file() with ts set to 0 on such
streams makes the mov demuxer return the right corresponding packets
(near the 0 timestamp) but set skip_samples to start_pad which is
incorrect as the audio decoder will discard the returned samples
according to skip_samples from the first packet it receives (which has
its timestamp near 0).
For example, considering the following audio stream with start_pad=1344:
[PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
Calling avformat_seek_file() with ts=0 makes the next call to
av_read_frame() return the packet with pts=-320 and a skip samples
side data set to 1344 (start_pad). This makes the audio decoder
incorrectly discard (1344 - 320) samples.
This commit makes the move demuxer adjust skip_samples according to the
stream start_pad, seek timestamp and first sample timestamp.
The above example will now result in av_read_frame() still returning the
packet with pts=-320 but with a skip samples side data set to 320
(src_pad - (seek_timestamp - first_timestamp)). This makes the audio
decoder only discard 320 samples (from pts=-320 to pts=0).
---
libavformat/mov.c | 23 ---
1 file changed, 20 insertions(+), 3 deletions(-)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index c6a2d9c388d..3215b536362 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -8122,6 +8122,22 @@ static int mov_seek_stream(AVFormatContext *s, AVStream
*st, int64_t timestamp,
return sample;
}
+static int64_t mov_get_skip_samples(AVStream *st, int sample)
+{
+MOVStreamContext *sc = st->priv_data;
+int64_t first_ts = st->internal->index_entri
Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Tue, 5 Jan 2021, Matthieu Bouron wrote:
Could you factorize this to a function? It seems you are doing exactly the
same thing here and below.
New patch attached.
[...]
diff --git a/libavformat/mov.c b/libavformat/mov.c
index c6a2d9c388d..e6d0de38c6f 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -8122,6 +8122,15 @@ static int mov_seek_stream(AVFormatContext *s, AVStream
*st, int64_t timestamp,
return sample;
}
+static int64_t mov_get_skip_samples(AVStream *st, int64_t seek_ts)
+{
Maybe cleaner to make "sample" a parameter instead of seek_ts.
+MOVStreamContext *sc = st->priv_data;
+int64_t first_ts = st->internal->index_entries[0].timestamp;
+
+/* compute skip samples according to stream start_pad, seek ts and first
ts */
+return FFMAX(sc->start_pad - (seek_ts - first_ts), 0);
Are you sure you don't need any time base correction here? Difference of
timestamps is in stream time base, but skip_samples is the number of
samples is in 1/sample_rate time base...
Also you are setting skip_samples for all streams, shouldn't you restrict
it to audio only, so return 0 for non-audio streams?
+}
+
static int mov_read_seek(AVFormatContext *s, int stream_index, int64_t
sample_time, int flags)
{
MOVContext *mc = s->priv_data;
@@ -8140,18 +8149,21 @@ static int mov_read_seek(AVFormatContext *s, int
stream_index, int64_t sample_ti
if (mc->seek_individually) {
/* adjust seek timestamp to found sample timestamp */
int64_t seek_timestamp = st->internal->index_entries[sample].timestamp;
+st->internal->skip_samples = mov_get_skip_samples(st, seek_timestamp);
for (i = 0; i < s->nb_streams; i++) {
int64_t timestamp;
-MOVStreamContext *sc = s->streams[i]->priv_data;
st = s->streams[i];
-st->internal->skip_samples = (sample_time <= 0) ? sc->start_pad :
0;
if (stream_index == i)
continue;
timestamp = av_rescale_q(seek_timestamp,
s->streams[stream_index]->time_base, st->time_base);
-mov_seek_stream(s, st, timestamp, flags);
+sample = mov_seek_stream(s, st, timestamp, flags);
+if (sample >= 0) {
+seek_timestamp = st->internal->index_entries[sample].timestamp;
This is destorying seek_timestamp, which seems unintended.
+st->internal->skip_samples = mov_get_skip_samples(st,
seek_timestamp);
+}
Regards,
Marton
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Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Mon, Jan 04, 2021 at 09:04:05PM +0100, Marton Balint wrote:
>
>
> On Mon, 2 Nov 2020, Matthieu Bouron wrote:
>
> > Currently skip_samples is set to start_pad if sample_time is lesser or
> > equal to 0. This can cause issues if the stream starts with packets that
> > have negative pts. Calling avformat_seek_file() with ts set to 0 on such
> > streams makes the mov demuxer return the right corresponding packets
> > (near the 0 timestamp) but set skip_samples to start_pad which is
> > incorrect as the audio decoder will discard the returned samples
> > according to skip_samples from the first packet it receives (which has
> > its timestamp near 0).
> >
> > For example, considering the following audio stream with start_pad=1344:
> >
> > [PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
> >
> > Calling avformat_seek_file() with ts=0 makes the next call to
> > av_read_frame() return the packet with pts=-320 and a skip samples
> > side data set to 1344 (start_pad). This makes the audio decoder
> > incorrectly discard (1344 - 320) samples.
> >
> > This commit makes the move demuxer adjust skip_samples according to the
> > stream start_pad, seek timestamp and first sample timestamp.
> >
> > The above example will now result in av_read_frame() still returning the
> > packet with pts=-320 but with a skip samples side data set to 320
> > (src_pad - (seek_timestamp - first_timestamp)). This makes the audio
> > decoder only discard 320 samples (from pts=-320 to pts=0).
> > ---
> > libavformat/mov.c | 18 --
> > 1 file changed, 16 insertions(+), 2 deletions(-)
> >
> > diff --git a/libavformat/mov.c b/libavformat/mov.c
> > index dd0db6bca79..f99cb0df25a 100644
> > --- a/libavformat/mov.c
> > +++ b/libavformat/mov.c
> > @@ -8098,20 +8098,34 @@ static int mov_read_seek(AVFormatContext *s, int
> > stream_index, int64_t sample_ti
> > return sample;
> >
> > if (mc->seek_individually) {
> > +MOVStreamContext *sc = s->streams[stream_index]->priv_data;
> > +
> > /* adjust seek timestamp to found sample timestamp */
> > +int64_t first_timestamp = st->internal->index_entries[0].timestamp;
> > int64_t seek_timestamp =
> > st->internal->index_entries[sample].timestamp;
> >
> > +/* adjust skip samples according to stream start_pad, seek
> > timestamp and first timestamp */
> > +int64_t skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> > first_timestamp), 0);
> > +st->internal->skip_samples = skip_samples;
> > +
>
> Could you factorize this to a function? It seems you are doing exactly the
> same thing here and below.
New patch attached.
[...]
Thanks,
--
Matthieu B.
>From 3c95d4d5e4505edf95b9cf4b5a632be98c069123 Mon Sep 17 00:00:00 2001
From: Matthieu Bouron
Date: Fri, 30 Oct 2020 15:38:51 +0100
Subject: [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
Currently skip_samples is set to start_pad if sample_time is lesser or
equal to 0. This can cause issues if the stream starts with packets that
have negative pts. Calling avformat_seek_file() with ts set to 0 on such
streams makes the mov demuxer return the right corresponding packets
(near the 0 timestamp) but set skip_samples to start_pad which is
incorrect as the audio decoder will discard the returned samples
according to skip_samples from the first packet it receives (which has
its timestamp near 0).
For example, considering the following audio stream with start_pad=1344:
[PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
Calling avformat_seek_file() with ts=0 makes the next call to
av_read_frame() return the packet with pts=-320 and a skip samples
side data set to 1344 (start_pad). This makes the audio decoder
incorrectly discard (1344 - 320) samples.
This commit makes the move demuxer adjust skip_samples according to the
stream start_pad, seek timestamp and first sample timestamp.
The above example will now result in av_read_frame() still returning the
packet with pts=-320 but with a skip samples side data set to 320
(src_pad - (seek_timestamp - first_timestamp)). This makes the audio
decoder only discard 320 samples (from pts=-320 to pts=0).
---
libavformat/mov.c | 18 +++---
1 file changed, 15 insertions(+), 3 deletions(-)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index c6a2d9c388d..e6d0de38c6f 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -8122,6 +8122,15 @@ static int mov_seek_stream(AVFormatContext *s, AVStream
*st, int64_t timestamp,
return sample;
}
+static int64_t mov_get_skip_samples(AVStream *st, int64_t seek_ts)
+{
+MOVStreamContext *sc = st->priv_data;
+int64_t first_ts = st->internal->index_entries[0].timestamp;
+
+/* compute skip samples according to stream start_pad, seek ts and first
ts */
+return FFMAX(sc->start_pad - (seek_ts - first_ts), 0);
+}
+
static int mov_read_seek(AVFormatContext *s, int stream_index, int64_t
sample_time,
Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Mon, 2 Nov 2020, Matthieu Bouron wrote:
Currently skip_samples is set to start_pad if sample_time is lesser or
equal to 0. This can cause issues if the stream starts with packets that
have negative pts. Calling avformat_seek_file() with ts set to 0 on such
streams makes the mov demuxer return the right corresponding packets
(near the 0 timestamp) but set skip_samples to start_pad which is
incorrect as the audio decoder will discard the returned samples
according to skip_samples from the first packet it receives (which has
its timestamp near 0).
For example, considering the following audio stream with start_pad=1344:
[PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
Calling avformat_seek_file() with ts=0 makes the next call to
av_read_frame() return the packet with pts=-320 and a skip samples
side data set to 1344 (start_pad). This makes the audio decoder
incorrectly discard (1344 - 320) samples.
This commit makes the move demuxer adjust skip_samples according to the
stream start_pad, seek timestamp and first sample timestamp.
The above example will now result in av_read_frame() still returning the
packet with pts=-320 but with a skip samples side data set to 320
(src_pad - (seek_timestamp - first_timestamp)). This makes the audio
decoder only discard 320 samples (from pts=-320 to pts=0).
---
libavformat/mov.c | 18 --
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index dd0db6bca79..f99cb0df25a 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -8098,20 +8098,34 @@ static int mov_read_seek(AVFormatContext *s, int
stream_index, int64_t sample_ti
return sample;
if (mc->seek_individually) {
+MOVStreamContext *sc = s->streams[stream_index]->priv_data;
+
/* adjust seek timestamp to found sample timestamp */
+int64_t first_timestamp = st->internal->index_entries[0].timestamp;
int64_t seek_timestamp = st->internal->index_entries[sample].timestamp;
+/* adjust skip samples according to stream start_pad, seek timestamp
and first timestamp */
+int64_t skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
first_timestamp), 0);
+st->internal->skip_samples = skip_samples;
+
Could you factorize this to a function? It seems you are doing exactly the
same thing here and below.
Thanks,
Marton
for (i = 0; i < s->nb_streams; i++) {
int64_t timestamp;
MOVStreamContext *sc = s->streams[i]->priv_data;
st = s->streams[i];
-st->internal->skip_samples = (sample_time <= 0) ? sc->start_pad :
0;
if (stream_index == i)
continue;
timestamp = av_rescale_q(seek_timestamp,
s->streams[stream_index]->time_base, st->time_base);
-mov_seek_stream(s, st, timestamp, flags);
+sample = mov_seek_stream(s, st, timestamp, flags);
+if (sample >= 0) {
+first_timestamp = st->internal->index_entries[0].timestamp;
+seek_timestamp = st->internal->index_entries[sample].timestamp;
+
+/* adjust skip samples according to stream start_pad, seek
timestamp and first timestamp */
+skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
first_timestamp), 0);
+st->internal->skip_samples = skip_samples;
+}
}
} else {
for (i = 0; i < s->nb_streams; i++) {
--
2.29.2
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Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Mon, Nov 23, 2020 at 05:43:06PM +0100, Matthieu Bouron wrote:
> On Tue, Nov 17, 2020 at 02:18:46PM +0100, Matthieu Bouron wrote:
> > On Mon, Nov 09, 2020 at 06:26:46PM +0100, Matthieu Bouron wrote:
> > > On Mon, Nov 02, 2020 at 12:42:19PM +0100, Matthieu Bouron wrote:
> > > > Currently skip_samples is set to start_pad if sample_time is lesser or
> > > > equal to 0. This can cause issues if the stream starts with packets that
> > > > have negative pts. Calling avformat_seek_file() with ts set to 0 on such
> > > > streams makes the mov demuxer return the right corresponding packets
> > > > (near the 0 timestamp) but set skip_samples to start_pad which is
> > > > incorrect as the audio decoder will discard the returned samples
> > > > according to skip_samples from the first packet it receives (which has
> > > > its timestamp near 0).
> > > >
> > > > For example, considering the following audio stream with start_pad=1344:
> > > >
> > > > [PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
> > > >
> > > > Calling avformat_seek_file() with ts=0 makes the next call to
> > > > av_read_frame() return the packet with pts=-320 and a skip samples
> > > > side data set to 1344 (start_pad). This makes the audio decoder
> > > > incorrectly discard (1344 - 320) samples.
> > > >
> > > > This commit makes the move demuxer adjust skip_samples according to the
> > > > stream start_pad, seek timestamp and first sample timestamp.
> > > >
> > > > The above example will now result in av_read_frame() still returning the
> > > > packet with pts=-320 but with a skip samples side data set to 320
> > > > (src_pad - (seek_timestamp - first_timestamp)). This makes the audio
> > > > decoder only discard 320 samples (from pts=-320 to pts=0).
> > > > ---
> > > > libavformat/mov.c | 18 --
> > > > 1 file changed, 16 insertions(+), 2 deletions(-)
> > > >
> > > > diff --git a/libavformat/mov.c b/libavformat/mov.c
> > > > index dd0db6bca79..f99cb0df25a 100644
> > > > --- a/libavformat/mov.c
> > > > +++ b/libavformat/mov.c
> > > > @@ -8098,20 +8098,34 @@ static int mov_read_seek(AVFormatContext *s,
> > > > int stream_index, int64_t sample_ti
> > > > return sample;
> > > >
> > > > if (mc->seek_individually) {
> > > > +MOVStreamContext *sc = s->streams[stream_index]->priv_data;
> > > > +
> > > > /* adjust seek timestamp to found sample timestamp */
> > > > +int64_t first_timestamp =
> > > > st->internal->index_entries[0].timestamp;
> > > > int64_t seek_timestamp =
> > > > st->internal->index_entries[sample].timestamp;
> > > >
> > > > +/* adjust skip samples according to stream start_pad, seek
> > > > timestamp and first timestamp */
> > > > +int64_t skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> > > > first_timestamp), 0);
> > > > +st->internal->skip_samples = skip_samples;
> > > > +
> > > > for (i = 0; i < s->nb_streams; i++) {
> > > > int64_t timestamp;
> > > > MOVStreamContext *sc = s->streams[i]->priv_data;
> > > > st = s->streams[i];
> > > > -st->internal->skip_samples = (sample_time <= 0) ?
> > > > sc->start_pad : 0;
> > > >
> > > > if (stream_index == i)
> > > > continue;
> > > >
> > > > timestamp = av_rescale_q(seek_timestamp,
> > > > s->streams[stream_index]->time_base, st->time_base);
> > > > -mov_seek_stream(s, st, timestamp, flags);
> > > > +sample = mov_seek_stream(s, st, timestamp, flags);
> > > > +if (sample >= 0) {
> > > > +first_timestamp =
> > > > st->internal->index_entries[0].timestamp;
> > > > +seek_timestamp =
> > > > st->internal->index_entries[sample].timestamp;
> > > > +
> > > > +/* adjust skip samples according to stream start_pad,
> > > > seek timestamp and first timestamp */
> > > > +skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> > > > first_timestamp), 0);
> > > > +st->internal->skip_samples = skip_samples;
> > > > +}
> > > > }
> > > > } else {
> > > > for (i = 0; i < s->nb_streams; i++) {
> > > > --
> > > > 2.29.2
> > > >
> > >
> > > Ping.
> > >
> >
> > Ping.
> >
>
> Ping.
>
Ping.
--
Matthieu B.
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Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Tue, Nov 17, 2020 at 02:18:46PM +0100, Matthieu Bouron wrote:
> On Mon, Nov 09, 2020 at 06:26:46PM +0100, Matthieu Bouron wrote:
> > On Mon, Nov 02, 2020 at 12:42:19PM +0100, Matthieu Bouron wrote:
> > > Currently skip_samples is set to start_pad if sample_time is lesser or
> > > equal to 0. This can cause issues if the stream starts with packets that
> > > have negative pts. Calling avformat_seek_file() with ts set to 0 on such
> > > streams makes the mov demuxer return the right corresponding packets
> > > (near the 0 timestamp) but set skip_samples to start_pad which is
> > > incorrect as the audio decoder will discard the returned samples
> > > according to skip_samples from the first packet it receives (which has
> > > its timestamp near 0).
> > >
> > > For example, considering the following audio stream with start_pad=1344:
> > >
> > > [PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
> > >
> > > Calling avformat_seek_file() with ts=0 makes the next call to
> > > av_read_frame() return the packet with pts=-320 and a skip samples
> > > side data set to 1344 (start_pad). This makes the audio decoder
> > > incorrectly discard (1344 - 320) samples.
> > >
> > > This commit makes the move demuxer adjust skip_samples according to the
> > > stream start_pad, seek timestamp and first sample timestamp.
> > >
> > > The above example will now result in av_read_frame() still returning the
> > > packet with pts=-320 but with a skip samples side data set to 320
> > > (src_pad - (seek_timestamp - first_timestamp)). This makes the audio
> > > decoder only discard 320 samples (from pts=-320 to pts=0).
> > > ---
> > > libavformat/mov.c | 18 --
> > > 1 file changed, 16 insertions(+), 2 deletions(-)
> > >
> > > diff --git a/libavformat/mov.c b/libavformat/mov.c
> > > index dd0db6bca79..f99cb0df25a 100644
> > > --- a/libavformat/mov.c
> > > +++ b/libavformat/mov.c
> > > @@ -8098,20 +8098,34 @@ static int mov_read_seek(AVFormatContext *s, int
> > > stream_index, int64_t sample_ti
> > > return sample;
> > >
> > > if (mc->seek_individually) {
> > > +MOVStreamContext *sc = s->streams[stream_index]->priv_data;
> > > +
> > > /* adjust seek timestamp to found sample timestamp */
> > > +int64_t first_timestamp =
> > > st->internal->index_entries[0].timestamp;
> > > int64_t seek_timestamp =
> > > st->internal->index_entries[sample].timestamp;
> > >
> > > +/* adjust skip samples according to stream start_pad, seek
> > > timestamp and first timestamp */
> > > +int64_t skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> > > first_timestamp), 0);
> > > +st->internal->skip_samples = skip_samples;
> > > +
> > > for (i = 0; i < s->nb_streams; i++) {
> > > int64_t timestamp;
> > > MOVStreamContext *sc = s->streams[i]->priv_data;
> > > st = s->streams[i];
> > > -st->internal->skip_samples = (sample_time <= 0) ?
> > > sc->start_pad : 0;
> > >
> > > if (stream_index == i)
> > > continue;
> > >
> > > timestamp = av_rescale_q(seek_timestamp,
> > > s->streams[stream_index]->time_base, st->time_base);
> > > -mov_seek_stream(s, st, timestamp, flags);
> > > +sample = mov_seek_stream(s, st, timestamp, flags);
> > > +if (sample >= 0) {
> > > +first_timestamp =
> > > st->internal->index_entries[0].timestamp;
> > > +seek_timestamp =
> > > st->internal->index_entries[sample].timestamp;
> > > +
> > > +/* adjust skip samples according to stream start_pad,
> > > seek timestamp and first timestamp */
> > > +skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> > > first_timestamp), 0);
> > > +st->internal->skip_samples = skip_samples;
> > > +}
> > > }
> > > } else {
> > > for (i = 0; i < s->nb_streams; i++) {
> > > --
> > > 2.29.2
> > >
> >
> > Ping.
> >
>
> Ping.
>
Ping.
--
Matthieu B.
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Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Mon, Nov 09, 2020 at 06:26:46PM +0100, Matthieu Bouron wrote:
> On Mon, Nov 02, 2020 at 12:42:19PM +0100, Matthieu Bouron wrote:
> > Currently skip_samples is set to start_pad if sample_time is lesser or
> > equal to 0. This can cause issues if the stream starts with packets that
> > have negative pts. Calling avformat_seek_file() with ts set to 0 on such
> > streams makes the mov demuxer return the right corresponding packets
> > (near the 0 timestamp) but set skip_samples to start_pad which is
> > incorrect as the audio decoder will discard the returned samples
> > according to skip_samples from the first packet it receives (which has
> > its timestamp near 0).
> >
> > For example, considering the following audio stream with start_pad=1344:
> >
> > [PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
> >
> > Calling avformat_seek_file() with ts=0 makes the next call to
> > av_read_frame() return the packet with pts=-320 and a skip samples
> > side data set to 1344 (start_pad). This makes the audio decoder
> > incorrectly discard (1344 - 320) samples.
> >
> > This commit makes the move demuxer adjust skip_samples according to the
> > stream start_pad, seek timestamp and first sample timestamp.
> >
> > The above example will now result in av_read_frame() still returning the
> > packet with pts=-320 but with a skip samples side data set to 320
> > (src_pad - (seek_timestamp - first_timestamp)). This makes the audio
> > decoder only discard 320 samples (from pts=-320 to pts=0).
> > ---
> > libavformat/mov.c | 18 --
> > 1 file changed, 16 insertions(+), 2 deletions(-)
> >
> > diff --git a/libavformat/mov.c b/libavformat/mov.c
> > index dd0db6bca79..f99cb0df25a 100644
> > --- a/libavformat/mov.c
> > +++ b/libavformat/mov.c
> > @@ -8098,20 +8098,34 @@ static int mov_read_seek(AVFormatContext *s, int
> > stream_index, int64_t sample_ti
> > return sample;
> >
> > if (mc->seek_individually) {
> > +MOVStreamContext *sc = s->streams[stream_index]->priv_data;
> > +
> > /* adjust seek timestamp to found sample timestamp */
> > +int64_t first_timestamp = st->internal->index_entries[0].timestamp;
> > int64_t seek_timestamp =
> > st->internal->index_entries[sample].timestamp;
> >
> > +/* adjust skip samples according to stream start_pad, seek
> > timestamp and first timestamp */
> > +int64_t skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> > first_timestamp), 0);
> > +st->internal->skip_samples = skip_samples;
> > +
> > for (i = 0; i < s->nb_streams; i++) {
> > int64_t timestamp;
> > MOVStreamContext *sc = s->streams[i]->priv_data;
> > st = s->streams[i];
> > -st->internal->skip_samples = (sample_time <= 0) ?
> > sc->start_pad : 0;
> >
> > if (stream_index == i)
> > continue;
> >
> > timestamp = av_rescale_q(seek_timestamp,
> > s->streams[stream_index]->time_base, st->time_base);
> > -mov_seek_stream(s, st, timestamp, flags);
> > +sample = mov_seek_stream(s, st, timestamp, flags);
> > +if (sample >= 0) {
> > +first_timestamp = st->internal->index_entries[0].timestamp;
> > +seek_timestamp =
> > st->internal->index_entries[sample].timestamp;
> > +
> > +/* adjust skip samples according to stream start_pad, seek
> > timestamp and first timestamp */
> > +skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> > first_timestamp), 0);
> > +st->internal->skip_samples = skip_samples;
> > +}
> > }
> > } else {
> > for (i = 0; i < s->nb_streams; i++) {
> > --
> > 2.29.2
> >
>
> Ping.
>
Ping.
--
Matthieu B.
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Re: [FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
On Mon, Nov 02, 2020 at 12:42:19PM +0100, Matthieu Bouron wrote:
> Currently skip_samples is set to start_pad if sample_time is lesser or
> equal to 0. This can cause issues if the stream starts with packets that
> have negative pts. Calling avformat_seek_file() with ts set to 0 on such
> streams makes the mov demuxer return the right corresponding packets
> (near the 0 timestamp) but set skip_samples to start_pad which is
> incorrect as the audio decoder will discard the returned samples
> according to skip_samples from the first packet it receives (which has
> its timestamp near 0).
>
> For example, considering the following audio stream with start_pad=1344:
>
> [PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
>
> Calling avformat_seek_file() with ts=0 makes the next call to
> av_read_frame() return the packet with pts=-320 and a skip samples
> side data set to 1344 (start_pad). This makes the audio decoder
> incorrectly discard (1344 - 320) samples.
>
> This commit makes the move demuxer adjust skip_samples according to the
> stream start_pad, seek timestamp and first sample timestamp.
>
> The above example will now result in av_read_frame() still returning the
> packet with pts=-320 but with a skip samples side data set to 320
> (src_pad - (seek_timestamp - first_timestamp)). This makes the audio
> decoder only discard 320 samples (from pts=-320 to pts=0).
> ---
> libavformat/mov.c | 18 --
> 1 file changed, 16 insertions(+), 2 deletions(-)
>
> diff --git a/libavformat/mov.c b/libavformat/mov.c
> index dd0db6bca79..f99cb0df25a 100644
> --- a/libavformat/mov.c
> +++ b/libavformat/mov.c
> @@ -8098,20 +8098,34 @@ static int mov_read_seek(AVFormatContext *s, int
> stream_index, int64_t sample_ti
> return sample;
>
> if (mc->seek_individually) {
> +MOVStreamContext *sc = s->streams[stream_index]->priv_data;
> +
> /* adjust seek timestamp to found sample timestamp */
> +int64_t first_timestamp = st->internal->index_entries[0].timestamp;
> int64_t seek_timestamp =
> st->internal->index_entries[sample].timestamp;
>
> +/* adjust skip samples according to stream start_pad, seek timestamp
> and first timestamp */
> +int64_t skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> first_timestamp), 0);
> +st->internal->skip_samples = skip_samples;
> +
> for (i = 0; i < s->nb_streams; i++) {
> int64_t timestamp;
> MOVStreamContext *sc = s->streams[i]->priv_data;
> st = s->streams[i];
> -st->internal->skip_samples = (sample_time <= 0) ? sc->start_pad
> : 0;
>
> if (stream_index == i)
> continue;
>
> timestamp = av_rescale_q(seek_timestamp,
> s->streams[stream_index]->time_base, st->time_base);
> -mov_seek_stream(s, st, timestamp, flags);
> +sample = mov_seek_stream(s, st, timestamp, flags);
> +if (sample >= 0) {
> +first_timestamp = st->internal->index_entries[0].timestamp;
> +seek_timestamp =
> st->internal->index_entries[sample].timestamp;
> +
> +/* adjust skip samples according to stream start_pad, seek
> timestamp and first timestamp */
> +skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
> first_timestamp), 0);
> +st->internal->skip_samples = skip_samples;
> +}
> }
> } else {
> for (i = 0; i < s->nb_streams; i++) {
> --
> 2.29.2
>
Ping.
--
Matthieu B.
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[FFmpeg-devel] [PATCH] avformat/mov: adjust skip_samples according to seek timestamp
Currently skip_samples is set to start_pad if sample_time is lesser or
equal to 0. This can cause issues if the stream starts with packets that
have negative pts. Calling avformat_seek_file() with ts set to 0 on such
streams makes the mov demuxer return the right corresponding packets
(near the 0 timestamp) but set skip_samples to start_pad which is
incorrect as the audio decoder will discard the returned samples
according to skip_samples from the first packet it receives (which has
its timestamp near 0).
For example, considering the following audio stream with start_pad=1344:
[PKT pts=-1344] [PKT pts=-320] [PKT pts=704] [PKT pts=1728] [...]
Calling avformat_seek_file() with ts=0 makes the next call to
av_read_frame() return the packet with pts=-320 and a skip samples
side data set to 1344 (start_pad). This makes the audio decoder
incorrectly discard (1344 - 320) samples.
This commit makes the move demuxer adjust skip_samples according to the
stream start_pad, seek timestamp and first sample timestamp.
The above example will now result in av_read_frame() still returning the
packet with pts=-320 but with a skip samples side data set to 320
(src_pad - (seek_timestamp - first_timestamp)). This makes the audio
decoder only discard 320 samples (from pts=-320 to pts=0).
---
libavformat/mov.c | 18 --
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/libavformat/mov.c b/libavformat/mov.c
index dd0db6bca79..f99cb0df25a 100644
--- a/libavformat/mov.c
+++ b/libavformat/mov.c
@@ -8098,20 +8098,34 @@ static int mov_read_seek(AVFormatContext *s, int
stream_index, int64_t sample_ti
return sample;
if (mc->seek_individually) {
+MOVStreamContext *sc = s->streams[stream_index]->priv_data;
+
/* adjust seek timestamp to found sample timestamp */
+int64_t first_timestamp = st->internal->index_entries[0].timestamp;
int64_t seek_timestamp = st->internal->index_entries[sample].timestamp;
+/* adjust skip samples according to stream start_pad, seek timestamp
and first timestamp */
+int64_t skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
first_timestamp), 0);
+st->internal->skip_samples = skip_samples;
+
for (i = 0; i < s->nb_streams; i++) {
int64_t timestamp;
MOVStreamContext *sc = s->streams[i]->priv_data;
st = s->streams[i];
-st->internal->skip_samples = (sample_time <= 0) ? sc->start_pad :
0;
if (stream_index == i)
continue;
timestamp = av_rescale_q(seek_timestamp,
s->streams[stream_index]->time_base, st->time_base);
-mov_seek_stream(s, st, timestamp, flags);
+sample = mov_seek_stream(s, st, timestamp, flags);
+if (sample >= 0) {
+first_timestamp = st->internal->index_entries[0].timestamp;
+seek_timestamp = st->internal->index_entries[sample].timestamp;
+
+/* adjust skip samples according to stream start_pad, seek
timestamp and first timestamp */
+skip_samples = FFMAX(sc->start_pad - (seek_timestamp -
first_timestamp), 0);
+st->internal->skip_samples = skip_samples;
+}
}
} else {
for (i = 0; i < s->nb_streams; i++) {
--
2.29.2
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