Skip to main content
Topic: Boost AC3 volume without re-encoding (Read 16213 times) previous topic - next topic
0 Members and 1 Guest are viewing this topic.

Boost AC3 volume without re-encoding

I've demuxed an AC3 file (DD 5.1 stream) from a DVD movie. Trouble is, i find the overall volume to be a little low. Is there a way to increase volume without reencoding, like mp3gain style?

Would like to avoid re-encoding as this will result in quality loss. Thanks.


Boost AC3 volume without re-encoding

Reply #2
ac3 is always low, enable DRC on your decoder (if its ac3filter turn on drc and crank up the preamp for it, maybe even move up the main gain)
Vorbis-q0-lowpass99
lame3.93.1-q5-V9-k-nspsytune

Boost AC3 volume without re-encoding

Reply #3
I'm not sure if this is the right thing to do here, but technically it is possible to do a lossless gain change like it can be done for AAC files -- but only in steps of 6 dB. (I guess no program has been written to do this yet. So this reply is not of much use for you unfortunately.)

I just wanted to mention it.


Sebi

Re: Boost AC3 volume without re-encoding

Reply #4
it's been more than 10 years since last replay.
maybe now there is a program that can boost AC3 volume losslessly like MP3 gain.
anyone?

Re: Boost AC3 volume without re-encoding

Reply #5
Technically, you could overwrite the pre-applied dynamic gain information, which is encoded into the track. But then you'd have to rely on the decoder having the AGC processing turned on. Plus, I haven't looked at a52dec, so I don't know the precision of the gain values.

Re: Boost AC3 volume without re-encoding

Reply #6
So there is no easy solution. I have to be expert to do this.

Re: Boost AC3 volume without re-encoding

Reply #7
Or wait for an expert to write software to do it for you.

Re: Boost AC3 volume without re-encoding

Reply #8
Closest solution I've come across is AC3Gain.
However, this is only a wrapper for Avisynth, which will eventually re-encode anyways.

Re: Boost AC3 volume without re-encoding

Reply #9
Technically, one could adjust the global dynamic gain fields, which are pre-calculated and encoded into the stream, but that relies on the user enabling dynamic gain control in their player.

Re: Boost AC3 volume without re-encoding

Reply #10
you may shove it into a container that allows you to store ReplayGain tags.
"matroska audio" would likely work.

this relies on user enabling ReplayGain volume matching, but this is something one'd normally do anyway, because otherwise music albums have the loudness all over the place.
Keep calm and opusenc --bitrate 128

 
SimplePortal 1.0.0 RC1 © 2008-2019