Video where speech is quiet and noises are loud

[A Traveller]

Hi all.

As the subject says, sometimes video downloaded from the web is very quiet when someone speaks but when there is a noise, it is very loud, so all throughout the video you have to keep raising and lowering the volume, which is annoying!

I have searched about this problem and some of the answers are to do with the way your surround sound speakers are set or that the room needs 'treating' and also something about adjusting the centre channel, however, none of that is relevant to me because I simply listen to the video on headphones! Is there any setting that can be changed in VLC or Ubuntu that can remedy this? One search mentioned turning off hardware acceleration but I can't find the corresponding setting in Ubuntu/VLC.

Thanks.

[jagabo]

Set the sound card controls to downmix 5.1 to stereo.

[hech54]

I somehow doubt that a video downloaded from the web has retained the 5.1 audio.

[jagabo]

I somehow doubt that a video downloaded from the web has retained the 5.1 audio.

Are you insane?

[hech54]

I somehow doubt that a video downloaded from the web has retained the 5.1 audio.

Are you insane?

Just wait.

[dphirschler]

If this is amateur footage, then it is not surprising. It's very common. The speaker may be farther away and so the sound is distant. And when the audience applauds it is very loud. This sort of thing can also happen when the person recording uses "auto" levels instead of manually setting the recording level. You might need to "shape" the volume. It's tedious, so it'd really only be worth it for videos you intend to keep. You might also try "compression". There's probably automated tools to help as well. I know I have used a tool to fix the audio in a concert which did this. But even after using it, I still had to manually shape the volume in sections.


Darryl

[intracube]

As the subject says, sometimes video downloaded from the web is very quiet when someone speaks but when there is a noise, it is very loud, so all throughout the video you have to keep raising and lowering the volume, which is annoying!

Hmm. Dialogue drowned out by music and explosions? Sounds like you're watching a Michael Bay movie

I have searched about this problem and some of the answers are to do with the way your surround sound speakers are set or that the room needs 'treating' and also something about adjusting the centre channel, however, none of that is relevant to me because I simply listen to the video on headphones!

First thing to do is check whether your videos are actually multichannel. mediainfo would give you that information, but if you don't have it installed, you can use VLC.

Open the file with VLC, click on Tools->Media Information and then the 'Codec Details' tab. The streams in the file should be listed. Check how many channels the audio stream has. There might also be more than one audio track (multiple languages, for example), but that's unlikely with a file from the net.

If it's only stereo, there's not a lot that can be done. If it's genuinely multichannel, then you can adjust the downmixing to make the centre channel more prominent in the mix.

Have you got any controls to adjust the centre channel with your audio mixer? Take a look at the screenshot here. For some reason I haven't got most of the controls in that image. I've only got a basic 2 channel soundcard, but I would've thought ALSA would still provide controls for the downmix - maybe there's a configuration option somewhere.

I couldn't find a way to adjust the downmixing with VLC.

I only know of one other way to downmix on the fly, and that's to use the command line version of mplayer. Let me know if you want to try this method.

[A Traveller]

Thanks for all the replies.

Set the sound card controls to downmix 5.1 to stereo.

I'm using onboard sound and the sound preferences only give very basic options, such as output volume, input volume, balance, etc. In my old Ubuntu, there was a long list of options in the hardware drop down box, however, at the moment there are only three! Analog Stereo Duplex, Analog Stereo Input and Analog Stereo Output. Where have all the other options gone? It was onboard audio on my old system as well.

If this is amateur footage

It's not amateur/home video.

I had to web search for Michael Bay!

Channels: 3F2R/LFE

A search of what that means led me here:-

http://forum.videolan.org/viewtopic.php?f=5&t=82777

My VLC output is Default, not ALSA.

Have you got any controls to adjust the centre channel with your audio mixer?

Not in my current setup.

Thanks for the help and suggestions.

[hech54]

2 days, 7 replies, and we still don't know if this file contains 5.1 audio....or poorly downmixed 2.0 audio that cannot be fixed by any of the methods described in the 7 replies.

[zoobie]

Although you can run it without, there's usually software that runs your mobo's onboard soundcard that gives you the extra options. For example, I'm running Realtek's HD audio manager as we speak.

[A Traveller]

Hi hech54. I thought the posts in the link I pasted meant that the sound was 5.1.

Hi zoobie. Remember I'm running Linux, so it's not a case of installing the software from a CD etc like in Windows. I've never needed to delve into the software aspect of audio before, just what's available in VLC.

Thanks.

[davexnet]

The other thing, if the player is using directshow, then ac3filter and/or the FFDshow/mixer comes into play.

I find FFDshow does a very good downmix to two channel.



Edit - oops, just realized the OP is Linux. Perhaps a better answer, relevant to the OP viewing the
files on the PC using headphones - if it really is 5:1 sound, use AVIdemux to convert it to
2 channel. You can apply DRC and normalization.

If it's 2-channel audio, you'll need an Audio Editor to perform compression and normalization.

[intracube]

I wrote quite a detailed post before realising there's some major inconsistencies in the stated channel order for multichannel file formats (WAV, AC3, AAC, etc). For example, this avisynth page says the order of AC3 files is:
front left, front centre, front right, rear left, rear right, LFE
while this page has a different ordering for AC3:
front left, front right, rear left, rear right, front centre, LFE

I've tried different configurations using mplayer's pan filter, and the following seems to extract just the centre channel from a file with AC3 audio:
mplayer -channels 6 -af pan=2:0:0:0:0:0:0:0:0:1:1:0:0 video.mp4
(from a terminal window in the same directory as your file). You might get lucky.

In practice you'd want to mix in some of the other channels, as the example above will only be in mono and will be excluding most of the audio mix. Try it as a first step anyway.

I need to investigate this further.

[hech54]

Hi hech54. I thought the posts in the link I pasted meant that the sound was 5.1.

Nope. Links to others talking about 5.1 audio doesn't mean your file has it.

[A Traveller]

Ok hech54.

Thanks intracube. I posted in case there was a simple setting that could be changed in existing software to remedy the problem. I most likely won't be doing any editing or other advanced tasks. If it's not something straightforward, it's ok, don't spend a lot of time on this issue. The problem is annoying but infrequent at present, so it's not TOO much of a big deal.

Thanks for all the help.