[Live-devel] frame skiping during streaming

[Andrew Voznytsa]

Ross Finlayson wrote:
> Neither of your choices is correct.  If you skip frames in the 
> underlying medium at the server (e.g., to seek, or to implement 'fast 
> forward'), it does not effect the presentation times of the stream 
> that actually gets sent.  "Presentation time" means just that - the 
> time that frames are 'presented' (displayed) on the receiver's 
> screen.  The receiver still sees a normal-looking stream; it's only 
> the underlying *content* that might have been shifted around.
> 
> So, using your example, *each* frame that you send has a duration of 
> MILLION.  The presentation time of the first frame that you send is 
> 0; the second 1*MILLION/fps; the third 2*MILLION/fps, etc.

Sorry, I misunderstood or it won't work.

If after sending frame 0 I skip N frames and assign presentation time 
1*MILLION/fps for N+1 frame then I'll just lose audio/video sync because 
I'm not skipping audio samples.

(Skipping was meant for video only, source media has two streams: audio 
and video).

If I plan to skip a few frames just after current frame then current 
frame should be displayed longer, until timeline won't reach 
presentation time of next frame.

It seems that current liveMedia implementation does not take into 
account presentation time when schedules next getNextFrame() but uses 
frame duration. Therefore, If I was skipping frames to lower bandwidth 
usage it won't help because video will be sent at the same rate.

--
Best regards,
Andrew Voznytsa