[Matroska-devel] MPEG2 in MKV!

Christian HJ Wiesner chris at matroska.org
Thu Oct 30 06:07:43 CET 2003


John,

congrats !!! It took you some time to make it, i know understanding the 
MPEG bitstream specs is not easy, but you always believed in that you 
can make it, and here you are !
About your questions :

spyder wrote:

>Hi,
>
>I finally finished this code and it seems to be working fine.  I am going to 
>test in a second on a MPEG1 clip out of curiosity.  But reading mpeg2 seems 
>fine.  I just need to implant this code in someone's muxer :)  Right now it 
>tells a lot of details about the frames such as whether it's progressive, 
>interlaced, pulldown-on-playback etc.
>
>The problem is how to mux this.  I think the GOP header should go with the 
>I-frame in a single block.
>
What are the alternatives ? Introducing a GOP element ? Could this maybe 
help for advanced editing ?

>  Also, there are repeated sequence headers before 
>most GOPs.  We can stick these with the I frame as well.
>
As above .... a sequence header element ? Do these have 'read-only' 
character or do they have to be modified on editing ?

>  The decoders should 
>have no problem with this.  The frames are in coding order.  And the problem 
>comes here:  Some frames in MPEG2 video actually decode to 2 frames on 
>playback to produce a 3:2 pulldown.  I can detect these frames with my code 
>but how do we timestamp them.
>
Timeslice ? What was the name of the feature again we introduced for 
handling of h.264 NALU's ?

>  I will be on IRC tomorrow (Thursday) at aroun 
>9am my time.  I think I am GMT-7 but not sure about that ;)
>  
>
I will soon be GMT +7 .... so we probably wont see each other on IRC for 
a while ;) ....

>/me goes to check that mpeg1 stream.
>IT WORKS!!!! W00T!!!!  MPEG1 is packetized too :O
>John
>
:) !   /me hugs John

Christian





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