[FFmpeg-devel] [PATCH] pulse: set default frame_size to 4608

Michael Niedermayer michaelni at gmx.at
Sat Jan 4 13:07:57 CET 2014


On Sat, Jan 04, 2014 at 10:01:39AM +0100, Federico Simoncelli wrote:
> On Sat, Jan 4, 2014 at 5:03 AM, Michael Niedermayer <michaelni at gmx.at> wrote:
> > On Sat, Jan 04, 2014 at 01:01:12AM +0100, Federico Simoncelli wrote:
> >> On Fri, Jan 3, 2014 at 6:41 PM, Michael Niedermayer <michaelni at gmx.at> wrote:
> >> I just found out that this may be related to the side data:
> >>
> >> [mp3 @ 0x191e320] skip 1105 samples due to side data
> >> [mp3 @ 0x191e320] skip 1105/1152 samples
> >>
> >> > frame_pts = 1105, frame_ts = 0.023021, base_ts = 0.000021
> >> > frame_pts = 1152, frame_ts = 0.024000, base_ts = 0.000021
> >> > frame_pts = 2304, frame_ts = 0.048000, base_ts = 0.000021
> >> > frame_pts = 3456, frame_ts = 0.072000, base_ts = 0.000021
> >>
> >> There's one thing that is not clear to me, if the side data are frames
> >> to be discarded, why is the pts adjusted?
> >
> > side data is "attached" to normal packets which contain normal data
> >
> > A encoder might add side data that for example says "dear decoder
> > if you decode this packet, discard the first 1000 samples, they
> > are just some kind of padding and the actual audio starts after that"
> 
> Ok, that's what I thought, and therefore I don't think that the pts
> should be adjusted.
> For example, in input you have nb_samples = 1024:
> 
> [ frame0 - frame1023 ] [ frame1024 - frame2047 ] ...
> 
> now the encoder adds 1105 frames of side data and changes nb_samples to 1152:
> 
> [ side data 1105 frames ] [ frame0 - frame46 ] [ frame47 - frame1198 ] ...
> 
> currently what avcodec_decode_audio4 does is discarding the side data
> but then adjusting the pts as if they were regular playable frames,
> and in fact frame0 is shifted to 0.023s (in my case), while in the
> original it's at 0.000s.

how is this related to pulse ?
can you show your "work in progress" patch? theres most
likely a bug in it if it causes something to go wrong with the
timestamps

[...]
-- 
Michael     GnuPG fingerprint: 9FF2128B147EF6730BADF133611EC787040B0FAB

The greatest way to live with honor in this world is to be what we pretend
to be. -- Socrates
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