[theora] Encoding vorbis with theora
Ernie Lyon II
fastawdtsi at gmail.com
Sun Jan 16 09:25:27 PST 2011
The "digital silence" is likely what I'm looking for, and from what you mentioned, vorbis having an efficient way of handling that tells me it's *exactly* what I'm looking for.
Now, my use case is a series of images set to a specific frame rate, and now I'm looking to add various bits of audio encoded throughout. Would you consider my theora stream to be "discontinuous?"
On Jan 16, 2011, at 11:37 AM, Gregory Maxwell <gmaxwell at gmail.com> wrote:
> On Sun, Jan 16, 2011 at 10:35 AM, Stuart Fisher <stuart.fisher at fig7.com> wrote:
>> Hi Ernie,
>> I was thinking about similar issues some time ago. I'd been writing some
>> code to playback theora clips.
>> The way I see it is that a player has to assume the audio track is always
>> a continuous audio stream. The video track, on the other hand, doesn't have
>> to be. The reason is that in order to playback the clip you need to have
>> synchronisation between the audio and video. The audio stream provides that
>> synchronisation (the player uses the audio clock to determine when video
>> frames should be displayed). So in other words I think you need to encode
>> the audio as a continuous stream (i.e. just encode silence between
>> the sections of audio).
>> That's the way I figured it out in my mind, but I wonder if there is a
>> defnitive explanation somewhere of how theora encoders and decoders should
>> handle discontinuity in the timeline.
> Both Theora and Vorbis are continuous stream types. Kate is an example
> of a discontinuous stream.
> Both formats have efficient ways of coding inactivity (digital silence
> in the case of vorbis, no motion in the case of theora), so you should
> just feed them inactivity when you want them to be inactive.
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