[Speex-dev] seeking in time, feedback+question

[Jim Crichton]

> I was trying to compress some big files and then to
> access to small portions and decode only those parts.
> I use the streaming mode(the sample codes provided on
> the web-site) without the Ogg packaging which seems
> useful to me for seeking in time.
> When I seek in time by just skipping packages, reset
> by:
> speex_decoder_ctl(state, SPEEX_RESET_STATE, NULL);
> and starting decoding, I see that the quality of
> decoding varies depending on the initial frame
> characteristics. It seems that the signal gets close
> to the original quite fast when the first frames are
> unvoiced. If I start decoding in the middle of a
> voiced chunk then decoding quality is comperatively
> much lower, more frames are needed until the signal
> gets closer to the original.
>
> This was the feedback part. So the obvious question
> is:
> do you know an easy way to get rid of this problem?

I do not know how you could get rid of the problem, but you could mask it by 
starting the decode a few frames early, and throwing away the audio for 
those early frames.  Then the decode state will have converged when you 
start decoding the audio that you want.

 Regards,

Jim Crichton