[FFmpeg-devel] MPEG index entries

Taylan O. Toygarlar tozgorto
Wed Nov 14 18:00:34 CET 2007

Hi Nico,

Nico Sabbi wrote:
> Il Wednesday 14 November 2007 03:17:18 Vinod G ha scritto:
>> Hi,
>> I have been working on a similar problem, so let me share my
>> findings.
>> You are right that the indexes generated inside
>> mpegps_read_pes_header are not keyframe indexes. But I still use
>> those indexes for the seek.
> of course, seeking can only happen at pes boundaries, but the position
> should be accepted only if the frame inside it is an
> I frame, something that you can't know until the parser kicks in

I am not very familiar with the interaction between the 
packets/parsers/demuxers. Does this mean it's not possible to create the 
index 'after' the parser "kicks in"?

I think we can detect existence of slices before the parsing stage, if 
the start code is between 0x01-0xAF. But on the same level, 0xB8 is the 
GOP start code, and it should be signaling us the keyframe. Or am I 
totally wrong on this?

Excuse me for my illiterateness on Mpeg Headers if thats too stupid a 

All the best,

Taylan Ozgur Toygarlar
Scientific Programmer, B.Sc.
Intelligent Systems Lab Amsterdam

Faculty of Science - Informatics Institute
University of Amsterdam
Kruislaan 403 1098 SJ
Amsterdam, The Netherlands

Telephone: +31 20 525 7555
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