TMPGEnc muxing buffer underflow

[Mocha]

After normalizing the volume for a mp2 from a mpeg2 source, I muxed audio and video, but at completion I received the error: 8 s packets cause buffer underflow........

Both the source mpeg2 and the muxed mpeg2 have slightly out of sync audio. Very slight.....fraction of a fraction of a second....but noticeable enough that after a while it looks like a kung fu movie. I plan on following the audio sync fix guide using goldwave, but my question is, how much time does a 8s packets buffer underflow translate into? Obvioulsy not 8 seconds because the audio is out of sync ever so slightly. Looks like the audio comes slightly before the video when I watch people talk.

Is there a program whereby one could manually alter the audio length and match it up with the video. In the goldwave guide, one must make a best guess, then actually mux the files then watch to test. I wish I could actually match up the audio and video side by side first before having to mux .


THx

[adam]

I think the relation between the amount of underflow and the amount of resulting desync depends largely on the playback device. Some hardware dvd players may be able to play that svcd back just fine. Oviously the best way to prevent desync is to prevent underflows in the first place.

If you want to make a compilant SVCD then make sure your bitrate does not exceed the standard; ~2600kbits for video, 2778kbits total (audio+video+any overhead) If you are getting underflows than your bitrate is too high. Either lower it or set the output to mpeg2 program stream. Of course this will create a non-standard SVCD (xsvcd) but you are already creating one simply by using too high a bitrate. You may want to use bbmpeg to multiplex instead as I personally believe it adheres to the SVCD spec better. If you do so simply use the standard SVCD option (maybe minus SVCD scan offsets and sequence header allign since these just take up space usually) but set the forced mux rate to 0.

Manually syncing any stream is tough, and mpeg2 streams are particularly difficult to work with. If your source was in sync then there is no reason why you should have to manually sync your resulting encode. Just make sure that you either adhere to the SVCD spec or else multiplex accordingly and you will not have to worry about sync problems.

[Mocha]

THe audio was slightly out of sync on the original mpeg2. Running both the muxed and original mpegs thru bitrate viewer, I get a peak of 2944 and average bitrate of 2351. Muxing with an audio of 192 instead of 224 bitrate reduces the error from 8s to 4 s packet.


How do I reduce the bitrate of the video without having to run it through TMPGENc, which would take hours?