Low audio from movie

[boyrune4]

Hi, Im not really good with this computer stuff so bare with me.
I have a movie that is supposedly ripped from a dvd. its an avi format.

The music is loud but you can barely hear the dialogue. I tryed looking for solutions like AC3 config and set the GAIN to high and it still had no difference. Does anyone know how to increase the audio

btw Im trying to play the video in the windows player and i have windows 7

[davexnet]

Perhaps ac3filter?
https://www.videohelp.com/tools/AC3-Filter

[jagabo]

Check your speaker setup. Your system is configured for a center channel speaker but don't have one.

[boyrune4]

I used AC3filter i said it in the orignial post , and i'm using headphones as well.

[Selur]

Here's how I 'picked it together'** why DVD->X conversions often seem to have the wrong dynamic, meaning some parts have to low and other too high volume:

• ac3* streams often have additional DRC infos that can tell the decoder to adjust the audio volumes
• a lot of decoders ignore these values and simply output the unmodified values (which is normal when reencoding)
  (some players and decoders ignore the drc info in the stream and simply use some internally specified drc values)

-> so your problem could be:

1. the decoder used ignores the drc infos
2. the ac3* you use does not have drc values, because is was reencoded without writing the drc flags or applying drc modifications during reencoding

about reencoding:
When reencoding an ac3* stream, you have normally these choices:

1. ignore the drc values (this is what most people do since they are not aware these infos exist)
2. decode the stream with a decoder that applies the drc values (caution, this can cause clipping if the base volume is not lowered) and reencode this modified stream.
3. decode the stream, apply your own drc changes to the audio and then reencode the resulting stream
4. decode and reencode the stream and add 'your own' or by the encoder provided drc infos to the stream (aften offers special
   'Dynamic Range Compression'- profiles)
5. do c. or d., but read out the original drc values (+ adjust them to limits that come due to your target format, i.e. low pass filtering, limited dynamic range) and use these. Problem with this method is: I never heard of a tool that is capable of doing this. :P

about playback:
If you playback an ac3* stream your decode, normally does one of the following:

1. decodes the stream and applies the drc values embedded in the stream (if present)
2. decodes the stream but ignores the drc values embedded in the stream (if present) and
   • does nothing further
   • applies internally some hidden drc values
   • allows the user to specify their own drc modifications in one or the other way (iirc. ac3filter offers some sliders to influence drc)

* probably also true for dts/dts-hd/truehd
** I never read something that addresses this directly, which is why I guess that most audio gurus are not as communicative/forthcoming as I would hope.

Cu Selur

Ps.: If someone things I'm wrong with the assumptions I 'picked together', please correct me and explain further.

[jagabo]

I used AC3filter i said it in the orignial post

You did not say that in your original post.

and i'm using headphones as well.

Once again, AC3 filter, or Windows' speaker configuration, is set up as if you have a center channel speaker. Since headphones don't have a center channel speaker all the center channel audio (most of the dialog) from your 5.1 AC3 audio is going nowhere. You need to set the AC3 filter or Windows to downmix 5.1 to stereo.

[boyrune4]

Here's how I 'picked it together'** why DVD->X conversions often seem to have the wrong dynamic, meaning some parts have to low and other too high volume:

• ac3* streams often have additional DRC infos that can tell the decoder to adjust the audio volumes
• a lot of decoders ignore these values and simply output the unmodified values (which is normal when reencoding)
  (some players and decoders ignore the drc info in the stream and simply use some internally specified drc values)

-> so your problem could be:

1. the decoder used ignores the drc infos
2. the ac3* you use does not have drc values, because is was reencoded without writing the drc flags or applying drc modifications during reencoding

about reencoding:
When reencoding an ac3* stream, you have normally these choices:

1. ignore the drc values (this is what most people do since they are not aware these infos exist)
2. decode the stream with a decoder that applies the drc values (caution, this can cause clipping if the base volume is not lowered) and reencode this modified stream.
3. decode the stream, apply your own drc changes to the audio and then reencode the resulting stream
4. decode and reencode the stream and add 'your own' or by the encoder provided drc infos to the stream (aften offers special
   'Dynamic Range Compression'- profiles)
5. do c. or d., but read out the original drc values (+ adjust them to limits that come due to your target format, i.e. low pass filtering, limited dynamic range) and use these. Problem with this method is: I never heard of a tool that is capable of doing this. :P

about playback:
If you playback an ac3* stream your decode, normally does one of the following:

1. decodes the stream and applies the drc values embedded in the stream (if present)
2. decodes the stream but ignores the drc values embedded in the stream (if present) and
   • does nothing further
   • applies internally some hidden drc values
   • allows the user to specify their own drc modifications in one or the other way (iirc. ac3filter offers some sliders to influence drc)

* probably also true for dts/dts-hd/truehd
** I never read something that addresses this directly, which is why I guess that most audio gurus are not as communicative/forthcoming as I would hope.

Cu Selur

Ps.: If someone things I'm wrong with the assumptions I 'picked together', please correct me and explain further.

I have no idea what is happening. Okay I'm not the great with computers but I have the AC3filter from this site. So can you tell me how i can fix the possible problems that are causing this.

[jagabo]

Go to the AC3 filter setup and set it to downmix to stereo (2.0):

https://forum.videohelp.com/threads/314504-VOB2MPG-%28converted-MPG-file-has-no-audio!%...=1#post1945220

[boyrune4]

Go to the AC3 filter setup and set it to downmix to stereo (2.0):

https://forum.videohelp.com/threads/314504-VOB2MPG-%28converted-MPG-file-has-no-audio!%...=1#post1945220

How do I know if the AC3 filter is takin effect because it doesn't do anything and at the main tab the output is already at stereo.

thanks for your help

[jagabo]

How do I know if the AC3 filter is takin effect

There's a setting to put it's icon in the System Tray (next to the clock) when it's in use. Enable that. If you don't see the icon in the System Tray it's not in use. You can configure it from that icon if necessary. If you don't get the icon something else is handling the audio. Many media players have built in AC3 decoders and downmixers. What player are you using? I see you mentioned "windows player" in your first post -- is that Windows Media Player?

[boyrune4]

How do I know if the AC3 filter is takin effect

I see you mentioned "windows player" in your first post -- is that Windows Media Player?

Yes, it is Windows media player I dont use any other program

[davexnet]

Perhaps use graphstudio to see what filters are being used. For example, FFDShow provides similar functionality
using the audio config/mixer tab.

Other situations where this problem arises is when an ac3 to 2-channel mp3 conversion was done,
and the "bad" dynamic range/low audio was "locked in".

[jagabo]

Yes, verify you have 5.1 audio. Use MediaInfo. GraphStudio (drag a video onto GraphStudio's window) will show you what filters are used to render the video and you can right click on any filter and select Properties to change the filter properties.

[boyrune4]

heres a screenshot, whats the next step?

http://imgur.com/7bYqi

[jagabo]

Why is MP3 Decoder DMO being used? Is your audio MP3 rather than AC3?

[boyrune4]

Why is MP3 Decoder DMO being used? Is your audio MP3 rather than AC3?

I guess so, its a movie an AVI format.

[jagabo]

Don't guess. You're wasting everybody's time. Use MediaInfo to find out. At least right click on the file and select Properties. But if it's MP3 you may be out of luck. It's likely whoever made it screwed up. Open the video in VLC. Select Audio -> Audio Channels -> Left, or Right. Dialog any better?

[hello_hello]

Here's how I 'picked it together'** why DVD->X conversions often seem to have the wrong dynamic, meaning some parts have to low and other too high volume:

• ac3* streams often have additional DRC infos that can tell the decoder to adjust the audio volumes
• a lot of decoders ignore these values and simply output the unmodified values (which is normal when reencoding)
  (some players and decoders ignore the drc info in the stream and simply use some internally specified drc values)

The dynamic range compression info may be present in the AC3 stream, but that doesn't mean you've got to use it on playback. I assume most DVD/Bluray players have an option to enable/disable DRC. With DRC disabled it doesn't mean the audio has the wrong dynamic, it means it's not being compressed, so it's more dynamic.... or to put it more accurately it's being played back with the original dynamic range.
I'd assume very few people apply DRC when converting AC3 because there's no going back.... the converted audio will be forever compressed. I don't think applying DRC when encoding is something many people would deliberately do.

Disabling DRC probably wouldn't cause clipping on it's own as such, although that problem's generally solved by performing some sort of 2 pass encoding to "normalise" the peaks. AC3 streams also contain "dialog normalization" which tells the player to adjust the whole playback level in order to keep dialog at the same level between movies/TV shows. It's standard practice to remove it when encoding too.
I think DTS and TrueHD audio also use dialog normalization, but I don't think they use DRC as AC3 does. Someone may be able to confirm that.

Mind you I doubt any of the above has anything to do with the original poster's audio problem. Either the channels were mixed down incorrectly when the AVI was encoded, or if the AVI contains multichannel audio it's possible the "channel assignments" were swapped around during the process for some reason. I've seen it a few times before.... 5.1ch audio with one of the rear and front channels swapped, or an LFE channel that actually contains the dialog instead of the LFE stuff..... I've "fixed" that sort of audio a couple of times by re-encoding it, while using ffdshow to do the decoding, and ffdshow's "swap channels" filter enabled to correct the channel assignments while re-encoding.

[boyrune4]

Don't guess. You're wasting everybody's time. Use MediaInfo to find out. At least right click on the file and select Properties. But if it's MP3 you may be out of luck. It's likely whoever made it screwed up. Open the video in VLC. Select Audio -> Audio Channels -> Left, or Right. Dialog any better?

I apologize if I wasted your time and I appreciate your help. What I meant was I wasn't sure how to check whether it was mp3. I checked it in MediaInfo now and it seems to be MPEG audio (MP3).
So basically I can't do anything about it?. Also I have no idea what VLC is.

[Wolfen]

VLC is a player that is way better than Windows Media Player I use Potplayer I like it. but you can edit mp3's if you want to try and this forum is for helping so if you need help ask away.

[davexnet]

I've "fixed" the volume on mp3's before on some crap I just wanted to watch once, then discard.
Audacity, or similar audio editor should do. Decrease the dynamic range and re-normalize.

[jagabo]

I checked it in MediaInfo now and it seems to be MPEG audio (MP3).

That reduces the number of possibilities.

I have no idea what VLC is.

It's a media player. I suggested it because it has the ability to play only the left or right channel of a stereo track. The last hope is that the two channels are out of phase so that the central channels are canceling each other out (highly unlikely). By playing only one channel that won't happen.