Improve sound in FlaskMPEG

[Rich 2]

I have encoded several movies with FlaskMPEG (DivX, MP3) but am always dissapointed with the sound quality after conversion. The dialog is too quiet compared to the rest. I have used tools to normalise extracted WAV files also but its still not that good. Too much background noise and not enough dialog.

Recently I loaded the new AC3FILTER_0_63b. It's really good you can increase the sound to the dialog channel (centre speaker) and it's the perfect solution but only when you play AC3 sound in WMP. When I use Flask it seems not to use this filter in the conversion process to MP3.

How can I get Flask to use this filter?

[Enchanter]

A much better way would be to disable sound processing in Flask and extract the audio separately. here's what you can do:
1. Rip audio to WAV using Graphedit/Vob2audio
2. If you wish, you can amplify the volume of the audio using an audio editor, such as Cooledit
3. Convert the WAV to MP3 using an mp3 encoder, such as LAME
4. Mux the MP3, with the video you have created, using nandub

To Create the required LST file, open a TXT file (renamed to LST) and input the following:
E:\Folder\VTS_01_1.VOB
E:\Folder\VTS_01_2.VOB
E:\Folder\VTS_01_3.VOB
E:\Folder\VTS_01_4.VOB
.
.
.
E:\Folder\VTS_01_x.VOB (The last VOB in the series)

The sound quality you will be getting should ensure that you won't be looking back to Flask (for sound processing) anymore.

[setarip]

If Flask is your "cup of tea" you might want to try the following procedures:


1) Convert to .AVI using Flask v.0.594PX3 (improved conversion time versus "plain vanilla" 0.594 - and less prone to lockup)
A) Using DivX v.3.11 codec (Fast Motion 910kbps, keyframe every 10 seconds)
B) Using PCM (uncompressed) audio at 48,000Khz (Maintains synchronization of audio and video)


2) Load .AVI into VirtualDub
A) Set "Video" to "Direct Stream Copying"
B) Set "Audio" to "Full Processing Mode"
C) Under "Audio", click on "Conversion", select "44,100Khz"
D) Under "Audio", click on "Compression" select "MP3", "44,100Khz", "96Kbps" (or higher)
E) Save revised .AVI with new filename

[Rich 2]

The methods you describe are useful and lead to improved sound quality. The only problem is once you go from AC3 to WAV using Flask, Graphedit/vob2audio the damage is done. The voice channel has been merged in with left, right and surround channels. Although you can normalise and increase the volume of before encoding to MP3 the damage is done. AC3Filter is better as it allows individual control over the voice channel, i.e. you can increase the volume of just this channel and reduce the surround channels. The only problem is that it is a direct show filter that is not used by Flask, Grapheedit/vob2audio in the decompression of AC3. I would really like to know how this particular filter could be used.

[Enchanter]

You should be aware that MP3 is a STEREO format (ie. once you convert a 5.1 AC3 sound to the stereo MP3, the conversion program will downmix the channels into left- and right-channels for the MP3).

Whatever AC3FILTER_0_63b is capable of doing, it works only on AC3 files (with their 6 discrete channels). It cannot apply its function on MP3 files, since the sound "structure" has already been altered.

Edit:
If you are so keen on controlling each channel on the AC3 file, I suggest you use AC3 file instead of MP3.

[Rich 2]

I have thought about keeping AC3 in the AVI but it adds another 500 mb, i.e. too big.

I know MP3 is strereo, and that's fine I just would like a little control on the mix down from 5.1 to stereo. I'm suprised I seem to be the only person who wants this.

Thanks for your help anyway. I will continue my search.

[Enchanter]

You could try this one out. Play the AC3 file, with all the desired filtering configurations, and record the output as a new WAV file. Once done, simply convert the WAV file to MP3.