[FFmpeg-devel] Bad audio DTSs in MXF clip

[Jorge Acereda]

On Nov 7, 2012, at 11:15 AM, Jorge Acereda wrote:

> 
> On Nov 6, 2012, at 8:21 PM, Michael Niedermayer wrote:
> 
>> On Tue, Nov 06, 2012 at 12:05:49PM +0100, Jorge Acereda wrote:
>>> Hi,
>>> 
>>> I've uploaded to the incoming folder a clip (bad_audio_dts.mxf) and a text describing the problem  (bad_audio_dts.txt). 
>>> 
>>> Looks like in that stream, the audio packet duration is fluctuating between a bit more than the timescale and a bit less. Due to the way libavformat/utils.c:compute_pkt_fields() rounds, it gets alternating durations 0 and 1 and that leads to bad timestamps.
>>> 
>> 
>>> I've included a patch in the text file (just changing the rounding mode to AV_ROUND_NEAR_INF).
>>> Is that the right thing to do?
>> 
>> no, the bug is in the demuxer, it MUST set a timebase that is accurate
>> enough to represent the durations reasonable exactly.
> 
> OK, so is it something along the lines of this?
> 
> <bad_audio_ts_2.patch>

This one breaks seeking in audio streams.

I've noticed a "mxf_edit_unit_absolute_offset(...) << 0)" instead of "... < 0)" in mxfdec.

Third attempt:

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