[mythtv] Question about the nuv seektable and keyframes

Isaac Richards ijr at po.cwru.edu
Sun Aug 10 12:19:16 EDT 2003


On Sunday 10 August 2003 09:58 am, Torbjörn Jansson wrote:
> I'm working on the seeking in my directshow filter and after looking at the
> nuv seektable i have some questions.
>
> The first entry in the seektable with keyframe_number=0 but there is
> atleast audio data before the position it points to, i know its not much
> data but anyway.
> I have asumed that keyframe=0 is the begining of both audio and video data.

Shouldn't be enough to matter, really.  It's likely bad data, anyway, since 
it's most likely immediately after a channel change.

> What does MythTV do when it seek to the begining? Does it seek to keyframe
> 0 and ignore the audio before that?

Yup.

> If i'm going to build the seektable manualy i just have to look for video
> sync frames and then calculate the keyframe number and position?

Aside from what Geoffrey just pointed out about the transcode/cutlist stuff, 
that's all you have to do.

> What about the rtjpeg sync frame ("RTjjjjjjjj") just before the video sync?
> Do i have to care about that one too?

Nope, mythtv ignores this frame completely.

Isaac


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