Audio codec

[bambam]

Hi i would like to know if it is possible that a audio and video sync problem can be cause by a bad audio codec or if it's impossible ?

[teegee420]

I have yet to encounter a bad codec per se. A/V sync problems are almost always file related.

[bambam]

Ok, not really a bad codec but a buggy one or
maybe a problem in the installation of a codec ?

[Hardcoreruss]

As T says I have never encountered this

[bambam]

thanx for the info

[Donny661]

I remember reading about the Fraunhofer mp3 ACM codec a while ago (I believe in some documentation of VirtualDub). First, it said that the Fraunhofer codec (one that comes with windows that only encodes up to 56kbps) had not been updated in a while because Fraunhofer started to only sell internal codec engines. Also, it said that the Fraunhofer codec was succeptible to variations in length of output and input, which would cause audio sync problems.

here is the part I read from VirtualDub help:

Do not correct MPEG layer III audio streams

Some MP3 codecs do not generate MP3 streams at exactly the same rate as specified in their audio format when 44.1KHz sampling rates are used -- this causes a small discrepancy in audio sync of around 0.5%. By default, VirtualDub recomputes the data rate and automatically corrects the audio header when MP3 compression is active. This option allows you to disable correction if it is causing problems, such as an MP3 stream being generated in a format that VirtualDub cannot parse correctly.

I've also heard about it when some people have wanted to use the LAME engine to make mp3s for avi files because LAME creates more accurate mp3 streams.

[bambam]

Thank you for your comment