Dynamic Range Control

[Xplorer4x4]

Not sure if this is the best place to put this or not but...

Dolby Digital uses a novel approach to applying Dynamic Range Control (DRC) to audio program material. Rather than compressing the dynamic range of the audio in an irreversible way, Dolby Digital encoders generate compression gain (also referred to as control) words that are carried in the Dolby Digital bitstream. When the bitstream is decoded, the compression gain words are applied to the audio material according to user settings. Dolby Digital decoders can be commanded to provide full, reduced, or even no dynamic range compression at all. This allows end users to adjust the amount of dynamic range compression to suit individual tastes and needs.

http://web.archive.org/web/20040716131627/http://www.dolby.com/tech/L.mn.0002.DDPEG1.pdf

As it is, when I play back a movie with AC3, audio is all over the place so one second I have to turn the volume up to hear voices/dialog but quickly turn the volume down when there is an explosion or something loud like that. Don't get me wrong, I want things like explosions to be a bit louder then dialog but I dont want it to blow out my TV speakers or force me to constantly adjust the volume. Now from what I understand this relies on both encoding and decoding, but when encoding to AC3, you are pretty much just extracting the audio so I think this would still be intact. Then it is up to the WD's Sigma 8655 chipset to apply the DRC. As I understand it this is part of the AC3 standards so this should be hardware independent and would be possible for the Sigma chipset to carry out. It seems this should be standard with in the WD but it isnt. How come? Is this something that is possible to implement this across the various base FWs?

[recliq]

There's absolutely nothing we can do about it, all the codec's and sigma drivers are closed source.
Only WD and/or Sigma can answer your question.

[RMerlin]

Quite a few receivers have an option to adjust the DRC. My fairly lowend Pionneer does, checks yours. Since the WDTV is only passing the AC3 stream to the receiver to decode, it'd be up to the receiver to handle DRC anyway, not the WDTV itself.

[Xplorer4x4]

Quite a few receivers have an option to adjust the DRC. My fairly lowend Pionneer does, checks yours. Since the WDTV is only passing the AC3 stream to the receiver to decode, it'd be up to the receiver to handle DRC anyway, not the WDTV itself.

What receiver? I just have a TV.

[crackinhedz]

The problem with listening to dialogue from the TV speakers is the TV is in stereo whereas the audio from the movie was mixed specifically with a "dialogue" channel. Most movies are either 5.1/6.1/7.1 and utilize the center channel for dialogue.

The TV has no center channel, so in essence it has to mix all of the channels together to play from the stereo speaker layout. This is most likely why you have to constantly turn up/down volume from the TV...best solution is to buy a receiver/speakers.

[Xplorer4x4]

best solution is to buy a receiver/speakers.

That is exactly what I was trying to avoid.
1. Cost - Sure it may not cost much, but its money I owuld rather spend elsewhere.
2. Disturbing the Neighbors - I live in an apartment complex.
I just extract the audio, apply Dynamic Range Compression to it using BeHappy , and then mux it back in with the video. Usually it does not take long.

[mad_ady]

@crackinhedz: I ran into the same problem with a couple of movies. Could hear background noises just fine, but the dialog was mute. Of course, it would play fine on the PC.
What do you suggest in terms of audio processing to remux a movie without this issue? I tried changing the codec, but it didn't work.

[Xplorer4x4]

@crackinhedz: I ran into the same problem with a couple of movies. Could hear background noises just fine, but the dialog was mute. Of course, it would play fine on the PC.
What do you suggest in terms of audio processing to remux a movie without this issue? I tried changing the codec, but it didn't work.

Could you provide a sample(say about 1 minute) of one of these videos. Are you using strictly a TV or a surround sound system? If the clip is 5.1 surround, for example, you could possibly use something like Soundforge(I am sure there are freewares out there capable of the same thing), and you might be able to boost strictly the center channel audio containing voice.

[crackinhedz]

Are you using strictly a TV or a surround sound system?

yes, this question can make all the difference. TV or HT system?


Xplorer, ever consider getting a cheap system (they make decent Onkyo systems that are very affordable) and during night time when neighbors are asleep just use some headphones?

me personally, I would not enjoy having to demux/remux each of my files for this purpose...in the end, you are left without the true audio mix...you might wish you didn't do that in the future?

[Xplorer4x4]

Are you using strictly a TV or a surround sound system?

Xplorer, ever consider getting a cheap system (they make decent Onkyo systems that are very affordable) and during night time when neighbors are asleep just use some headphones?

me personally, I would not enjoy having to demux/remux each of my files for this purpose...in the end, you are left without the true audio mix...you might wish you didn't do that in the future?

I just have no interest in some low shelf product. Not that I only buy top shelf, but I spend my money wisely. Plus there is no such thing as nighttime in my case lol. I have neighbors below,above and behind me. To sum up there work habits, lets just say they cover all 3 shifts.

Headphones? I can not even fathom how much that would suck. Headphones are fine for jamming music on my comp while I work or play, but watching a movie? That would be a negative on many levels. Now I have personally never seen wireless headphones, but if they do exist I guess they aren't cheap. Dragging chords across the floor is just seems like ancient practice these days. :p Not to mention when I watch a movie, it is usually me and my girlfriend,whom I live with, laying on the couch. Headphones would kind of suck.

As for muxing, I don't enjoy it lol, but it's not that I hate it. I have a pretty high end PC, so mux.demux times are pretty minimal. I can have DTS or AC3 audio demuxed from a 720p Blu-Ray rip in about 2 or 3 minuets(assuming a file size of about 10GB or less).If the audio is DTS,then I have to convert it with BeHappy(This app seems a lil slow, so lets say 5 min on the conversion) Soundforge doesnt accept AC3 so I use Foobar for a quick conversion to WAV. Thats about 3 minuets or so. Takes maybe 3 min to find a good section of audio to use for calculating the RMS level. Run my AC3 audio through BeHappy which takes maybe 10-15 seconds to configure. Then remux. All in all it takes about 10 minuetes-15 min to do. I am usually on the comp during this time as I tend to be ADD on the computer trying to do to many things at once. If there was enough interest I would gladly document the procedure I use if others find it useful.

As for in the future,I have considered the fact I could regret it sure. One day I may very well, but that is not in the foreseeable future so I am fine with this for now. Even if we moved to a house next year, there are more important things on my list then obtaining a surround sound system. Sure I may not have to worry about disturbing neighbors as much by the fluctuating audio levels, but I would still rather have the audio at a relatively consist level.