Using Besweet to make ac3 file from mp2 -> distorted soun

[lchiu7]

Trying to create a DVD with ac3 (2 channel sound). Input is raw avi file huffyuv compression (720x480) and 16 bit 48Khz PCM sound. Initially ran it through tmpgenc to make a DVD compliant mpeg2 file, then extracted the mpg sound using tmpgen de-multiplex. That sound plays fine. However after putting it through besweet the sound is distorted and crackly. If I extract the original PCM file as wav and pass that through Besweet, the sound is fine. Any ideas?

Thanks

[DJRumpy]

If you can extract the original wav, and convert it in BeSweet wihtout issue, why do you need help?

When working with converison projects, you should recompress your source as little as possible. In your case, your compressing your audio, demuxing it, and recompressing it again.

You should simply extract the audio from your source, and encode it directly to your desired output (in this case AC3) using BeSweet. Then it's a simple matter of muxing it together with your video (TMPGenc can do this via FILE | MPEG TOOLS).

[lchiu7]

Because when I process the original uncompressed avi file through tmpgenc. I use the source range setting to cut of bits of the video. That means the final mpg file is the video file I want. Converting the extracted wav file from the original avi file and converting to ac3 means I lose the editing cuts and can't readily multiplex the video and ac3 sound.

Only other option is to use a different package to edit the raw avi file first, then extract the wav file and then process. Hard to find shareware packages than can do editing of avi files

[DJRumpy]

I understand. TMPGenc can be a little tedious to do that. You can do it in TMPGenc, however, without compressing the audio. At least I think you can . I've never tried it, as I don't use TMPGenc. Put all of your edits into TMPGenc regarding source range, and then from the FILE menu, select FILE | OUTPUT TO FILE, and select WAV. I don't know if TMPGenc will adhere to your source range edits, but it might.

Alternately, you can use AVISynth, which is free, to do both the audio, and video edits. Much easier, although you would have to learn a new tools. You would use the TRIM command to segment out the sections you want to keep. It automatically segements the audio as well. You simply supply it with START and STOP frame numbers. You can get those from virtualdub. You use the TRIM command to specify start/stop frames. The syntax look like this: Trim( startframe,stopframe)

Used in a script, it would look like this:

AVISource("c:\folder\movie.avi")
clip1=Trim(0,15000)
clip2=Trim(16000,30000)
clip3=Trim(31000,45000)
clip4=Trim(46000,0)
clip1++clip2++clip3

The above script would output a video, consisting of frames:
0 to 15000
16000 - 30000
31000-45000
and
46000- end (the 0 end the endframe position basically means 'to the end')

It then joins them seemlessly into one video. The audio is also limited to only those frames you specify. This script can be dropped into almost any encoder like TMPGenc, with no further editing work needed.

[lchiu7]

Actually I didn't complete my post. I found I could make the ac3 file sync'ed to the video using tmpgenc by selecting Linear PCM as the output sound format. This then creates two files, a m2v file and wav file (I think). I then ran the wav file through Besweet and then multiplexed them back together with ifoedit en route to authoring the DVD. This works okay but hardly seems worth the trouble now when I compare the mpeg sound with the ac3 sound when played on my various DVD players. Unless I can find a way of making my own 5.1 original sound source so I need ac3 sound on the DVD, it doesn't seem necessary

[DJRumpy]

I thought of that, but I wasn't able to change the output to anything other than MPEG-1 Layer 1 or Layer 2. Curious that yours lets you. I'm not worried about it, as I don't use TMPGenc.
I agree regarding the audio. You could use either the MP2, or the AC3. They would sound about the same, and they'll be about the same size. Unless you have a true 5.1 source, you don't gain much using 2-Channel AC3 over MP2, except for compatability on all NTSC players. Most will play DVD's with MP2 regardless.