How to replace very low audio on music videos

[shopkeeper]

I have a few music videos in my collection which are sourced from dvd's and ripped to .avi files. The image quality is excellent but in some the audio is very low. One or two have sound which is hardly audible , no matter how much I turn up the volume.

I also have the same music videos, but ripped from tv where the audio is pretty loud and clear. Is there a way I can replace the audio in the dvd rips with the louder audio from the tv rips or even from mp3 files?

If this was possible, I imagine it would also mean having to carefully 'line-up' (sorry.. I am a kind of a newbie.. so I dont know the technical term) the audio from one source so that it was in-synch with the video to the other.

Could someone please describe how I would do this, the steps required and the software I would need?

I mentioned I was kind of a newbie, since years ago I did use to convert movie files in .avi format to DVD using TMPGENc and VirtualDub. But this was the days before divX/Xvid compatible dvd players and I was basically following step by step information I had gleamed from this forum.

Any help or advice would be great.

Thanks

[bobkart]

Demultiplexing an audio/video file allows you to create a separate file for just the audio and another for just the video.

Then the reverse function, multiplexing, allows separate audio and video files to be combined into one.

This is usually easier when the files are relatively uncompressed, such as with DV-AVI and WAV files. You say you have AVI files but that doesn't really say much since AVI is just the container format. Maybe they are DivX? You'd like to avoid having to re-encode (compress) either the audio or video, so that requires you to find multiplexers/demultiplexers that can operate on the particular format of audio/video involved.

Then of course there will be synchronization issues, not only for the starting points, that they line up, but also that the speeds are not ever so slightly different between the two original clips (the one with good video and the one with good audio). That second problem would give you a video that slowly lost audio/video synchronization as the clip progressed. Difficult to fix.

I'm a bit surprised to hear that a commercial DVD (they were commercial weren't they?) would have "way too quiet" audio for music videos.

[shopkeeper]

Thanks for your reply. Here are the details of the 2 files.



and



What multiplexers/demultiplexers software would you recommend given the details of the files.

Thanks

Demultiplexing an audio/video file allows you to create a separate file for just the audio and another for just the video.

Then the reverse function, multiplexing, allows separate audio and video files to be combined into one.

This is usually easier when the files are relatively uncompressed, such as with DV-AVI and WAV files. You say you have AVI files but that doesn't really say much since AVI is just the container format. Maybe they are DivX? You'd like to avoid having to re-encode (compress) either the audio or video, so that requires you to find multiplexers/demultiplexers that can operate on the particular format of audio/video involved.

Then of course there will be synchronization issues, not only for the starting points, that they line up, but also that the speeds are not ever so slightly different between the two original clips (the one with good video and the one with good audio). That second problem would give you a video that slowly lost audio/video synchronization as the clip progressed. Difficult to fix.

I'm a bit surprised to hear that a commercial DVD (they were commercial weren't they?) would have "way too quiet" audio for music videos.

[mats.hogberg]

Demux and mux: VirtualDubMod

/Mats

[bobkart]

Thanks Mats.

[shopkeeper]

Demux and mux: VirtualDubMod

/Mats

Thankyou Mats.

Then of course there will be synchronization issues, not only for the starting points, that they line up, but also that the speeds are not ever so slightly different between the two original clips (the one with good video and the one with good audio). That second problem would give you a video that slowly lost audio/video synchronization as the clip progressed. Difficult to fix.

Could you please give me an idea of how I would go about matching the starting points exactly?

[bobkart]

Adjust it until it's right? Some authoring applications will let you specify an audio delay/offset. But no software can tell you that the audio is synchronized with the video. Only you can tell that by watching/listening to it. So if by watching and listening to it, you see/hear that it is off, try to estimate by how much it is off. Then dial that offset into the authoring process. Repeat until satisfied.

Maybe someone else out there has a better way, I'm just taking a shot here, I've never actually done it.

[mats.hogberg]

Wel, that's basically how I do it. Boring, tedious, and rarely worth the trouble. Try to find a distinct action/sound, like a door slamming to make the guesswork somewhat easier.

/Mats

[AlanHK]

I see from GSpot that the audio is MP3. So if you demux this you'll have an MP3 file, and at 320k it should be excellent quality. Pump this up to max volume on a stereo and check if the quality really is okay, or if it's muffled or clipped. If it's good, you can just adjust the volume level without losing quality using MP3Gain. Then mux the new version back with the video. Should be exactly the same sync as the original.

I've noticed this in some AVIs where there is a very loud section (e.g., gunfire) and apparently this has been used as a reference when normalising the sound. If that's the case you'll have to turn off the "don't clip" option in MP3Gain to get normal volume in the track as a whole.

[shopkeeper]

Thanks for all your help everyone!

I see from GSpot that the audio is MP3. So if you demux this you'll have an MP3 file, and at 320k it should be excellent quality. Pump this up to max volume on a stereo and check if the quality really is okay, or if it's muffled or clipped. If it's good, you can just adjust the volume level without losing quality using MP3Gain. Then mux the new version back with the video. Should be exactly the same sync as the original.

This method worked really well. The sound is much louder now. I wasnt sure how to demuxs and muxs in VirtualDubMod, but after doing a search on the forums I quickly found my answer (jman98 post in this thread https://forum.videohelp.com/viewtopic.php?t=307084&highlight=mux+virtualdubmod. I thought I would post for reference.)

I was wondering if there was something similiar to mp3gain for wav files since VirtualDub also allows you to save out WAV files. I was thinking, if a video wasnt encoded with mp3 compression it would maybe be possible to save out a .WAV file, increase the gain on that and then muxs that back into the video? Or would I have to take some other steps first?

[mats.hogberg]

Most audio editirs can do that - GoldWave, Audacity to name a couple of them.

/Mats

[AlanHK]

I was wondering if there was something similiar to mp3gain for wav files since VirtualDub also allows you to save out WAV files. I was thinking, if a video wasnt encoded with mp3 compression it would maybe be possible to save out a .WAV file, increase the gain on that and then muxs that back into the video? Or would I have to take some other steps first?

The reason I suggested MP3gain is that your audio is already MP3. Changing the level like this does not degrade the quality; it's simply changing a scale factor. Every time you change formats you lose some quality. Going MP3 to WAV and back to MP3 will degrade the sound a little. But if you're doing anything more complicated than this level change you generally have to decompress the audio.

Audacity has an "amplify" filter that boosts volume on a curve.

[shopkeeper]

Great! Thanks for the help.

One last question. I also have some .VOB files with very low audio, such as this file :



When I open the file with VirtualDubMod it prompts me with the following message :



I am assuming I can again extract a .WAV file and use the programs suggested already to increase the volume, but I have a couple of questions.

Which of the audio streams would it be better to work with if I decided to use VirtualDubMod.

Also, is there another method maybe using software more tailored for this media format to increase the volume in a VOB file as, if i'm not mistaken, the audio isnt compressed yet?

Thanks again. Im learning alot by trying to do this.

[bobkart]

I would always prefer the WAV file over a compressed audio file. Assuming of course that there aren't problems with the WAV file.

Applications could be written that increase the volume of audio tracks multiplexed with video, and perhaps they even have. But of course internally they would just be demiltiplexing the audio tracks, increasing the volume, and multiplexing it back together. The same thing you are doing with separate applications. So the motivation for someone to create such a specialized application is reduced, since the same thing can already be done with existing applications, albiet with a few more steps.

One philisophy when designing applications is to have each one do one thing well (That's the Unix/Linux philosophy). By combining the pieces appropriately you build your solution as needed.

The other philosophy (Microsoft) is to make each application do as many things as possible. I'll leave it at that.

[AlanHK]

I am assuming I can again extract a .WAV file and use the programs suggested already to increase the volume, but I have a couple of questions.

Which of the audio streams would it be better to work with if I decided to use VirtualDubMod.

Also, is there another method maybe using software more tailored for this media format to increase the volume in a VOB file as, if i'm not mistaken, the audio isnt compressed yet?

It's a bit odd to have two audio streams. Demux them both and see if they're identical -- in a movie you might have a dubbed track, or a commentary. Or perhaps the person making it added the AC3 but forgot to delete the PCM (which is huge -- can take up as much space as the video).

Any audio editor at all can handle PCM, that's one advantage, it's like BMP for images, inefficient but simple. If it's there and okay, use it. I'd convert it to AC3 or MP2, but if you aren't tight for space on the DVD I suppose it doesn't matter.

You can't use MP3gain though, that's only for MP3.

[shopkeeper]

Applications could be written that increase the volume of audio tracks multiplexed with video, and perhaps they even have. But of course internally they would just be demiltiplexing the audio tracks, increasing the volume, and multiplexing it back together. The same thing you are doing with separate applications. .

I did some more investigation around this forum and came across Avidemux2. I have been using it very successfully (with a little help http://www.avidemux.org/pun/viewtopic.php?pid=15447#p15447) to increase the volume without any apparent change to the video.

For anyone who does a search and finds this topic useful, i've copied the steps to do this (atleast for a VOB/mpg file) from the above link

Load your files
Audio filter gain ->automatic
Audio codec twolame
Output format mpeg PS
Video codec copy
Save as foo.mpg

Thanks to everyone for there posts and help

[AlanHK]

came across Avidemux2.

Thanks; very interesting, I'd just assumed it was a demuxer for AVI files, which I could do otherwise, so I never bothered to check it out. Names can be deceptive when the app evolves.
Looks something like Avisynth+VirtualDub (which names are less straightforward, but at least not contradictory).