[FFmpeg-devel] [RFC/PATCH] matroska timestamps not always pts

[Måns Rullgård]

"John Kelley" <john at kelley.ca> writes:

> On 11/20/07, M?ns Rullg?rd <mans at mansr.com> wrote:
>> "elupus" <elupus at ecce.se> writes:
>>
>> > "Uoti Urpala" <uoti.urpala at pp1.inet.fi> wrote in message
>> > news:1195598562.18396.9.camel at symbol.nonexistent.invalid...
>> >> On Sun, 2007-11-18 at 23:11 +0100, elupus wrote:
>> >>> Apperently the timestamps stored in matroska container can mean
>> >>> different things. For native tracks they normally mean pts,
>> >>> while for others this isn't always the case.
>> >>>
>> >>> The case i'm trying to nail here is the ms compatibility case. In this
>> >>> case,
>> >>> timestamps should correspond to the frame numbers in avi. This patch
>> >>> makes
>> >>> demuxer only set the correct timestamp (dts/pts) in the packet.
>> >>
>> >> Does some spec say they "should correspond" to frame numbers? Or are you
>> >> only saying this because you've seen (invalid?) files generated by
>> >> someone which do this?
>> >
>> > Well, i didn't get that exact wording from Haali, what I got was that
>> > "timestamps should be treated as timestamps are treated in avi." And since
>> > there is no such thing as timestamps in avi,
>>
>> this must mean that matroska timestamps should be ignored.
>
> Absolutely not, why would you discount them when it is only one very
> seldom used feature of matroska that causes them to not be ideal?
> (MPEG-4 in compatibility mode)

I was joking.  That said, I must add that the matroska timestamp
design (I'm uncertain whether they've had too much or too little of
it) doesn't exactly make life easy for demuxer writers (I've never
tried to write a matroska muxer).

-- 
M?ns Rullg?rd
mans at mansr.com