Date: Mon, 22 Dec 1997 17:32:40 +0100 (MET) From: Luigi Rizzo <luigi@labinfo.iet.unipi.it> To: rhh@ct.picker.com (Randall Hopper) Cc: hasty@rah.star-gate.com, multimedia@FreeBSD.ORG Subject: Re: MPEG audio/video sync & Re: These mtv video pauses are murder Message-ID: <199712221632.RAA02664@labinfo.iet.unipi.it> In-Reply-To: <19971222121942.13340@ct.picker.com> from "Randall Hopper" at Dec 22, 97 12:19:23 pm
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> Luigi Rizzo: > |I suppose the problem if any will be in the capture phase. We have a > |way to timestamp (using the cpu clock) incoming video frames (do you > |use that ?), but e.g. for audio you cannot rely on the sample rate > > I do store off a timestamp for each frame of data (video frame + > accumulated audio to that point). This is used to know how many frames we > missed, which is how many times the preceeding frame is replicated in the > mpeg_encode input stream to normalize the video back up to the full FPS rate. well my point was that the right (I would even say "the only") approach to get timing info in a video+audio steam is to use the audio sample clock. It makes life easier in the reproduction phase since it is much easier then to keep video in sync. Probably my previous posting was confused enough to obscure the above point. Cheers Luigi -----------------------------+-------------------------------------- Luigi Rizzo | Dip. di Ingegneria dell'Informazione email: luigi@iet.unipi.it | Universita' di Pisa tel: +39-50-568533 | via Diotisalvi 2, 56126 PISA (Italy) fax: +39-50-568522 | http://www.iet.unipi.it/~luigi/ _____________________________|______________________________________
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