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View Full Version : AAC - AC3 transcoding


citro
8th August 2006, 13:14
I have an 1.4GB video file: x264 video, AAC audio, Matroska container. Nice quality, but I'd like to watch it on my DVD/DivX standalone player rather my computer.

So, let's the fun begin: demux, AviSynth + VirtualDub for video transcoding (XviD, 2-pass). It's time for audio transconding (AAC - AC3), and the troubles begin.

First, I try besweet + belight: fatal error - MAXFRAMESIZE. I search the forum but no help here.

Next try - graphedit. No error message but the output file is way too small (the AAC file is 230MB and the resulting WAV is only 100MB).

Finally, I use Winamp with disk writer plugin and it seems to work - the output WAV is 4GB. WAV - AC3 transcoding (besweet) works.

Not it's time for questions:
1. I read that sometimes there is a problem with the order of channels when using besweet for transcoding from one 5.1 source to another. I don't have a 5.1 system, so I wonder if the way I did it is likely to cause me problems.
2. The error message in besweet (MAXFRAMESIZE) is related to a bug in the program or a problem with the audio stream?

tebasuna51
8th August 2006, 15:07
A exact 4 GB wav, 6 channel, 16 bit Int, 48 KHz have a duration of 2:04:16.

- If your wav have exactly 4 GB and video duration > 2:04:16 maybe your audio is clipped.

- BeSweet don't accept wav 16 int > 2 GB

- BeSweet-ac3enc need a wav with channels remapped (Use WaveWizard instead)

- BeSweet/WaveWizard-ac3enc make ac3 streams at 50% of input wav volume.

To transcode aac -> ac3 use faad (http://www.rarewares.org/files/aac/faad.zip) (output wav int 16 bit WAVE_FORMAT_EXTENSIBLE and can be > 4 GB), and aften (http://forum.doom9.org/showthread.php?p=847746#post847746) (not need remapping, input can be > 4 GB WAVE_FORMAT_EXTENSIBLE)