ChickenMan

How to Convert Audio to AC3
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BeSweet with BeSweet GUI or AC3-Machine have been traditionally used to convert audio to AC3, however, it does not produce a compliant AC3 audio file. While most players can play them back okay (mine does !), many can't (Pioneer, Phillips, Samsung, etc.) and simply gives no audio output. So I describe here 3 programs that can be used to convert your audio files to compliant AC3 format needed for DVD playback.

To make fully DVD Compliant DVD's, the audio is required to be in AC3 or WAV form as a minimum. While WAV files are very large in size, almost all retail DVD's have AC3 with possibly other audio (DTS, MPEG Stereo, LPCM, etc). NTSC DVD's must have an AC3 audio track plus others if needed, while PAL DVD's can have an MP2 audio track on its own. Experience has shown many PAL players still have trouble with MP2 audio though. For all DVD's AC3 audio is the way to go for trouble free playback.


The 3 programs I mention here all have different pros and cons, surely one will suit your needs. They are:


1. ffMPEG with its ffMPEGGUI. This is freeware and will convert MP3, WAV or MP2 to AC3. Also does 44.1khz to 48khz sampling if needed and is quite fast. No Normalizing of sound levels. From http://www.dvdrhelp.com/tools.php?tool=434

2. TMPGEnc Sound AC3 Plugin. This is a low cost plugin intended for their Authoring program but can be run as a standalone. Converts WAV only to AC3, no 44.1khz to 48khz sampling and is reasonably fast. No Normalizing of sound levels. From http://www.pegasys-inc.com/e_main.html

3. Sonic's AC3Enc (comes free with the VERY expensive Sonic Scenarist 2.6, 2.7 or 3.0). This program has many options available, however, converts WAV only to AC3, no 44.1khz to 48khz sampling and is very slow. It does Normalize the sound levels though. From http://www.sonic.com/products/scenarist/default.asp


This guide is intended to supplement my AVI to DVDR Tutorial based on DVD2SVCD, however, it can be used for/with other audio sources and Tutorials.

DVD2SVCD extracts either an MPA (actually MP3) or AC3 audio file from the original AVI. It then converts this to a WAV file and finally normalized the sound level and produces an MP2 file. There is no 44.1khz to 48khz sampling done at any stage if the original was in that form. If the AVI contained AC3 audio, then simply use the Extracted_audio_1.mp3 and no conversion needed (many need to be "fixed" though with BeSplit). The WAV or MP2 file is what we will convert.

The easiest program to use is ffMPEGGUI as it converts the normalized MP2, converts 44.1 to 48khz and all done in 1 fast pass (though in my expreiance it will give Audio sync problems when converting 44.1 to 48 khz). TMPGEnc AC3 Plugin and Sonic AC3Enc will produce better quality AC3 as they convert from the WAV. The WAV will need to be normalized and converted to 48khz (BeSweet or GoldWave is good here) if you use TMPGEnc AC3 plugin, no normalizing needed if using Sonic AC3Enc.


1 - ffMPEG

Run ffMPEGGUI and then:


1. Click the Audio Source Browse button and load in your MP2 (or WAV) file.

2. Set the Bitrate to 224 (what you used in DVD2SVCD or leave at default 192).

3. Click the Audio Output Browse button and select a suitable name.

4. Click the Convert button. It will take 1 - 2 min to do the conversion.





2 - TMPGEnc AC-3 Plugin

Run TMPGEncSoundPlayer and then:


1. Click the ENCODE button.

2. Highlight the Dolby Digital (AC-3) Encoder/Decoder option.

3. Load in your Encoded_audio_1.mp2.wav file produced by DVD2SVCD (or any other WAV file thats 16bit Stereo 48khz) by using Drag-and-Drop technique. Drag as many WAV files into here as you like and it will convert them all in Batch mode.

4. Double click the Settings button and change the Bitrate to 224 (what you used in DVD2SVCD or leave at default 192).

5. Click the Browse button and point to a folder where you want the final AC3 file to be saved.

5. Click the Encoding button. It will take 1-2 min to do the conversion.





3 - Sonic's AC3Enc

Run Sonic's AC3Enc and then:


1. Tick the 2-ch Interleaved Input box.

2. Load in your Encoded_audio_1.mp2.wav file produced by DVD2SVCD (or any other WAV file that 16bit Stereo 48khz).

3. Change the Output file name if you wish.

4. Change the bitrate to 224 by clicking the Edit button. The default is 192. Do NOT change anything else in there.

5. Click the Start Encoding button. It can take 5-10min to do the conversion.




ChickenMan (c)2005 - Jan 2005

Attached Images

ac3enc.gif (23.0 KB, 743 views)

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Cheers,
CM

Please don't PM me with technical questions, use the Forum, that's what it's here for.