low bitrate converting AC3 to MP2 using BeSweet

[WhipHubley]

hi - when converting an AC3 stream (448 kb/s 5CH CBR, according to GSpot) to MP2 using BeSweet (for eventual DVD authoring) I cannot keep the bitrate setting I choose.

when asking BeSweet to either keep it at 448, or slightly lower to 384 (and I can see that the correct arguments are being passed) it still lowers it right down to 128kb/s.

this sounds barely audible.

can someone please explain why this is, and if there is anything I can do about it?

thanks!

[WhipHubley]

here's the log if it helps diagnose the problem...

BeSweet v1.4 by DSPguru.
--------------------------
Using azid.dll v1.8 (b825) by Midas (midas@egon.gyaloglo.hu).
Using lame_enc.dll v1.28 (4/6/2002), Engine 3.92 <http://www.mp3dev.org/>.

Logging start : 03/02/04 , 12:42:31.

C:\Program Files\BeSweet\BeSweet\BeSweet.exe -core( -input D:\Captures&Rips\testing.ac3 -output D:\Captures&Rips\testing - New - [02.03.2004] - [12.42.31].mp2 -logfile C:\Program Files\BeSweet\BeSweet.log ) -azid( -c light -L -3db --maximize ) -toolame( -m s -b 384 -e )

[00:00:00:000] +------- BeSweet -----
[00:00:00:000] | Input : D:\Captures&Rips\testing.ac3
[00:00:00:000] | Output: D:\Captures&Rips\testing - New - [02.03.2004] - [12.42.31].mp2
[00:00:00:000] | Floating-Point Process: Yes
[00:00:00:000] +-------- AZID -------
[00:00:00:000] | Input Channels Mode: 3/2, Bitrate: 448kbps
[00:00:00:000] | Output Stereo mode: Dolby surround compatible
[00:00:00:000] | Total Gain: 25.592dB, Compression: Light
[00:00:00:000] | LFE levels: To LR -3.0dB, To LFE 0.0dB
[00:00:00:000] | Center mix level: BSI
[00:00:00:000] | Surround mix level: BSI
[00:00:00:000] | Dialog normalization: No
[00:00:00:000] | Rear channels filtering: No
[00:00:00:000] | Source Sample-Rate: 48.0KHz
[00:00:00:000] +-------- LAME -------
[00:00:00:000] | Bitrate method : CBR
[00:00:00:000] | MP3 bitrate : 128
[00:00:00:000] | Channels Mode : Joint Stereo
[00:00:00:000] | Error Protection: No
[00:00:00:000] +---------------------
[00:01:20.064] E7: CRC error
[00:01:20:064] Conversion Completed !
[00:01:20:064] Actual Avg. Bitrate : 128kbps
[00:00:10:000] <-- Transcoding Duration
Logging ends : 03/02/04 , 12:42:41.

[WhipHubley]

incase anyone else find this useful...

it seems as though I've extracted the AC3 audio incorrectly. I used nandub and saved it as a WAV file, and it looks as though BeSweet doesn't like it (although it does convert it).

I think I need to use virtualdubmod to extract the AC3 stream correctly.

by the way, I just converted the AVI movie that the stream was from, and AVI2DVD handled it perfectly. it used BeSweet too, and it was fine.

in fact, the resultant MPEG2 file with MP2 192kb/s audio sounded much better than the original AVI! (which I was playing through media player classic - the only app I could get to play AC3)

[KpeX]

I'm not sure toolame supports such a high bitrate (384/448). Remember that MP2 is only stereo whereas AC3 is six channel, MP2 doesn't need that high of a bitrate. For fixing the AC3-wav extracted with nandub, BeSplit can be used. D2S does work well for such conversions, doesn't it ;).