I have two avi (xvid) files (50 min/700mb each) and want to join them before I convert them to MPEG2. Two files had different audio (mp3 and ac3). Since I found coverting them to ac3 incur a low volume issue, I converted them into mp2 by using ffmpeggui (mp2, 48000, 224kbps). Then, I disable original audio in virtualdubmod and add mp2 (new) audio and save it. At this point, new avi files (with new audio) plays perfect. But, when I join them by using virtualdubmod (I also tried virtualdub and avi joiner), only the second avi (originally ac3) have audio sync issue (audio is faster than video). The first part (avi) (originally mp3) does have that issue. I am wondering if this is related to a conversion from ac3 to mp2. It doesn't look like it is related to a joining software becaues I tried two different software and got exactly the same result (audio sync in the second avi).
I just found that the sync problem has nothing to do with original files or two different audio file format. I put two files in reverser order and join them for a test. The second avi files (that had sync problem...originated from ACS) plays just fine. Instead, the first avi file (that played fine) had sync problem now. So, the problem occurs at the time of joining.
Yep, I would guess that the two .avi had a different bitrate or different framerates..and when you joined them..you should use the "full processing" mod on each .avi first and create a "dubbed" .avi for each...keeping the output settings the same for both "new" .avi...then join these two .avi files with the same bitrate/framerate. It's just a suggestion....more work.
AVI don't support MP2, only DVD do. Use FFMPEG GUI to convert the sond to AC3, instead. And remember: AC3 192 kbps has the same quality than MP2 224 kbps. MP2 is a mpeg stuff, good only for DVD (which support also AC3) or (S)VCD. AVI support only MP3 and AC3. If you put a MP2 sound in an AVI, you spoil your movie (I hope you can decompress the sound alone to WAV and, the, re-build a MP3 CBR or an AC3 stream with it).
