On 2023-12-15 12:43 am, Michael Niedermayer wrote:
On Tue, Dec 12, 2023 at 04:50:08PM +0530, Gyan Doshi wrote:
During a resampling operation where
1) user has specified first_pts
2) SWR_FLAG_RESAMPLE is not set initially (directly or otherwise)
3) first_pts has been fulfilled (always using hard compensation)
then upon first encountering a delay where a soft compensation is
required, swr_set_compensation will lead to another init of swr which
will reset outpts to the specified firstpts thus leading to an output
frame having its pts = firstpts. When the next input frame is received,
swr will see a large delay and inject silence from firstpts to the
current frame's pts. This can lead to severe desync and in worst case,
loss of audio playback.
Parameter initcount added to keep track of swr_init calls of the swrcontext
and to ultimately avoid enforcing firstpts again.
Fixes #4131.
---
libswresample/swresample.c | 7 +++++--
libswresample/swresample_internal.h | 1 +
libswresample/version.h | 2 +-
3 files changed, 7 insertions(+), 3 deletions(-)
Would it work to instead set firstpts = AV_NOPTS_VALUE on allocation
and then use firstpts == AV_NOPTS_VALUE to detect if it has been set
already ?
If that workes, that seems simpler than counting init
That does work. I avoided it since I didn't know if I needed to make
swr_alloc2() or change in place.
v2 sent.
Regards,
Gyan
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