[vlc] Re: Problem playing MPEG-PS files with mpeg4video

[Nico Sabbi]

Gildas Bazin wrote:

>On Wednesday 26 January 2005 08:58, Nico Sabbi wrote:
>  
>
>>Måns Rullgård wrote:
>>    
>>
>>>Nico Sabbi <nsabbi at tiscali.it> writes:
>>>      
>>>
>>>>Gildas Bazin wrote:
>>>>
>>>>        
>>>>
>>>>>Ok, the main problem here is that we don't have access to the frame
>>>>>rate information for this kind of streams so we can't really
>>>>>interpolate the timestamps, thus we rely on each frame having at
>>>>>least a DTS.
>>>>>Do you know if there's a way to find out the frame rate info ?
>>>>>     
>>>>>
>>>>>          
>>>>>
>>>>this is what I implemented for mplayer:
>>>>
>>>>take 3 video frames and store
>>>>- from the vol header the time_resolution
>>>>- from the vop headers the 3 time_increments
>>>>
>>>>calculate the minimun difference between the 3 time_increments, say diff
>>>>fps = timeinc_resolution / diff
>>>>
>>>>This method works also when there are b-frames because they have to be
>>>>in the right order, e.g.
>>>>   
>>>>        
>>>>
>>>You could also be nice to decoder and store the frame rate in the
>>>PSM.  Have you tried whether VLC doing so makes VLC any happier?
>>>
>>>
>>>      
>>>
>>VLC doesn't seem to be able to mux mpeg4 in mpeg-ps: the resululting files
>>contain only audio.
>>It would be nice to describe the framerate with a descriptor, but which?
>>
>>    
>>
>
>Thanks for the time_increment trick. I'll implement that ASAP.
>  
>

good :)

>I just managed to get hold on an ISO 14496-2 draft and apparently it is also 
>possible to store the framerate in the VOL (the fixed_vop_time_increment 
>field) so maybe you should consider using this to make things simpler ?
>  
>

right, but only xvid stores it, while all other mpeg4 encoder don't use 
this field,
so it would be a short-lived trick.


>As for the MPEG PS muxer in VLC, you're quite right that it doesn't support 
>MPEG4 yet.
>
>  
>

I hope it will be implemented :)

>--
>Gildas
>
>  
>

Bye,
    Nico

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