mp2 volume change

[Brent212]

I had an mpg file that was dvd-compliant (captured with hauppauge 250 in DVD Standard setting), but the sound was too loud. So I demuxed the file with tmpgenc to get a .mpv and a .mp2 file. Now I want to lower the volume of the .mp2, but can't figure out the best way to do it. I can open it up in a program like audacity, but after altering the volume level, I have to re-encode it with lame, and then I can't re-mux the resulting .mp3 with the original .mpv. So I'm thinking that I should save it as a .wav from audacity and then somehow get it muxed back with the .mpv file.

So my question is this: What would be the best way to get a wav file to a dvd-compliant format, and then muxed with a dvd-compliant .mpv? The main thing I don't want to do is re-encode the video before burning it to a dvd. Can TMPGEnc do this, and if so, how?

It'd be nice to be able to change the volume of the .mp2 without re-encoding, but I don't think it's possible, except maybe with besplit, but I can't find any info on using besplit to lower the volume of a .mp2. The closest thing I can find to that is using it to normalize a .mp2 (using "-ota( -G max)" ), which doesn't help.

Thanks for any suggestions.

[bottle-necked]

Hi Brent, this is a fairly easy fix. There are plenty of ways to do this so this is only one of those ways, ok.

I would load the original MPEG file into VirtualDub Mod, click Stream, then Stream List, then click Save Wav. You will then be asked to choose a new filename and location for the new WAV file. VirtualDub Mod will create a PCM uncompressed WAV file.

Take the WAV file into your application and lower the volume to a point you like then save it back in PCM uncompressed WAV format. For this task I would use Creative WaveStudio that came with my sound card. You need to use whatever program you like, just watch the save routine so you keep the 'same' settings going.

To get the WAV back to MP2 format you can use Tmpgenc. I use the standard mode (not the Wizard). Click "ES Audio Only", delete any filename that may be on the Video Source line (wierd quirt in the program), load or drag your corrected WAV file onto the "Audio Source" line, set an output filename and location you like, click on Settings and input your "original" bitrate, then "Run" the program.

If you want to you can "Multiplex" those streams back using Tmpgenc Mpeg Tools and the Multiplex command and recreate your corrected MPEG2 file.

This is not hard to do - but watch your settings as you go along. ok
Good luck.

[Brent212]

Awesome, thanks for the advice.

When multiplexing the fixed mp2 and the mpv back together, what setting should I use? I've noticed there's an SVCD setting, and some other MPEG2 settings, as well as an MPEG1 VCD setting. I was thinking the best one would be MPEG2 VBR Program or something like that. I don't have the program installed where I'm at right now, so I can't look at the actual options.

Thanks again

[bottle-necked]

Tmpgenc will (should) autoset that for you.
Good luck.

[Brent212]

Ok, so I demuxed, opened the .mp2 up in audacity, lowered the volume, saved it as a wav, used TMPGEnc, along with toolame.exe (from doom9), to encode the wav back to a .mp2, and finally re-muxed that back together with the .mpv in TMPGEnc to get a complete .mpg with quieter sound. One problem - there is a very noticeable delay in the sound now. Something will happen in the video, and about .5 - 1 second later you'll hear it. I opened both the original .mp2 and the re-encoded .mp2 in winamp and they both seem identical as far as length and speed. I can pick a spot in the track, watch the counter and listen, and then play the other file and do the same, and they are identical as far as I can tell. The length being the same also indicates this.

So that narrows the problem down to the multiplexing done in TMPGEnc. I actually used TMPGEnc Plus to do the muxing and de-muxing, if that matters. I used regular TMPGEnc to do the encoding of the wav to mp2 because Plus gave me a program error.

Is there a way to correctly multiplex the new .mp2 and .mpv files? Can I do it somehow in TMPGEnc Plus and just specify a delay in the audio so it'll match up (which would be annoying, but I could probably make it about right).

Also, the new complete .mpg is about 2,590 MB, whereas the original complete .mpg is about 2,670 MB. What's the reason for this? Is there missing header information? Is some of this missing info needed for using the file to author a DVD? I'm worried that this will cause my authoring software (TMPGEnc DVD Author) to re-encode the file when creating the burnable files.

Thanks for any help,
Brent