Page 1 of 1

Audio & Video Synchronization

Posted: Mon Apr 28, 2008 6:48 pm
by cruizm
Hi

I am using ProgDVB version 5.14.03 for Windows XP 64.
The box is an AMD 64 dual core 4600+ with 8 Gb of ram
with a Pinnacle PCTV USB stick.
I don't understand anything about video nor audio, so I
am not sure if the problem I have is related to the Progdvb
app or it's a problem with the decoders or anything else.
The thing is that the audio is not synchronized with the video.
The audio has around one second of delay. It's a bit annoying
to hear words when the lips have stopped moving.

I have these settings:

Video: ffdshow Video Decoder
Audio: MPEG Audio Decoder

Any suggestion ?

Thanks

Carlos

Posted: Mon Apr 28, 2008 10:08 pm
by Juergen
Proper co-working of codecs, renderer, graph is a pretty tricky issue.
And it can depend on several other conditions as well, like VGA (part) hardware support, sound card settings and effects, whatever you may think of...
Each extra reprocessing is suspected to cause an additional delay (latency).

There's no general solution for this, as computers do differ a lot these days.

First of all, pull back the playback / timeshift slider a little, find out, if this helps.
If so, you're probably having DVB specific synching issues, that base on VBR streaming offsets. Change renderer and / or codecs.

Video decoding needs time (a GOP, at least) and by this causes a delay. Video is coded with variable bit rate, by this buffer filling varies. Audio normally needs less time, but players normally synch both by use of the stream internal time codes, if those are correct. There are many chances for mistakes...
This is not just about codecs and renderer, as a possible HW support from the VGA card may interfere with decoding delay as well. If so, disable to compare.

Things may get easier when using audio and video decoders, that are meant to match together, like (exactly) those that came with your original software, for example.

Some other codecs may have internal settings for basic snyching delay correction, one way or the other.

Audio & Video Synchronization

Posted: Thu May 08, 2008 1:42 pm
by cruizm
Thanks a lot. I had not even realized this slide bar existed. I have shitfted it a bit and it is perfect now !!!! The voice and the video is perfectly synchronized.

Cheers

Carlos