[Live-devel] Full HD Contents. trickplay question (with VLC)

[Peng]

>> Note the file "ChunMyung1.ts".  This file was created by applying 'trick play' to the original file, with a scale factor of 1 - i.e., by running:
>>             testMPEG2TransportStreamTrickPlay ChunMyung.ts 0 1 ChunMyung1.ts
>> Because our 'trick play' works by using I-frames only, this file effectively consists just of the i-frames from the original file.  If you play this file in VLC, you can see that the I-frames freeze starting at about the 10 second mark, and do not resume until about the 1 minute mark.  Does anyone know why?
>>
>> For another illustration of this, note the file "ChunMyung1-30.ts".  This file was created by applying 'trick play' to the original file, with a scale factor of 1, but starting at the 30 second mark - i.e., by running:
>>             testMPEG2TransportStreamTrickPlay ChunMyung.ts 30 1 ChunMyung1-30.ts
>> If you play this file in VLC, you can see that the video is 'empty' until about the 30 second mark (i.e., corresponding to about 1 minute into the original video).  Does anyone know why?
Hi, Ross.

I just check ChunMyung.ts and ChunMyung1-30.ts. The empty 30 seconds has 
nothing to do with MPEG-TS container, it is caused by picture timing 
information carried within SPS and SEI of H.264 encoding. This point is 
that though testMPEG2TransportStreamTrickPlay picks I frames out, it 
does not modify the associated timing information accordingly.

A feasible method to avoid this is to remove vui_parameters() (possibly 
together with hrd_parameters()) in SPS and to remove SEI completely. It 
seems that somebody has already done something very similar:
http://forum.doom9.org/showthread.php?t=152419

Regards

-- 
Peng