Is there any way to play AC-3 on a PC without DRC?

[deleted user]

I usually prefer lossless audio so I didn't notice yet, but I did a few experiments on Mission Impossible: Fallout and was surprised how jarring the difference was.

What I tried was MPC-HC and VLC. I included both the original AC-3 track and a FLAC track, which is just the AC-3 track converted with ffmpeg with the "drc_scale 0.0000000" option.

In MPC-HC they both sound pretty underwhelming, not sure why.

In VLC, the FLAC track sounds very noticeably better.

And don't take my word for it, here is proof that I'm not imagining it (just recorded the playing audio via Audacity):


In VLC, I disabled DRC in the A/52 codec settings (A/52 is a synonym for AC-3 afaik) and also normalization in general. Logically both outputs should have been identical, but they were not, as you can see. The dialogue seems about the same in volume, but the gunshots afterwards are very clearly attenuated while playing the AC-3 version. In fact, as you can tell, the second gunshot should actually be even louder, but in the AC-3 version it's quieter than the first one!

As a result the AC-3 sounds very boring while the FLAC sounds very exciting and dynamic. Really makes quite the difference.

Just to clarify, in MPC-HC I also disabled all normalization and AC-3 DRC options I know of.

So all in all, I don't currently see any good way to properly play AC-3 on a computer without transcoding it by hand. Of course this is no justification to distribute bloated FLACs instead of the raw AC-3, but it does create a real problem at least for playback purposes.

How do you guys deal with this? Do you all have Dolby Decoders and use bitstreaming or play directly via Blu Ray players? And if so, how do you know your players aren't doing the same thing?

[Chewtobacca]

For processing an AC-3 track on the fly, I use AC3Filter in concert with MPC-HC.  (The former will pop up automatically when you play a video using the latter.)  Give it a shot and have a look at the settings to see if it meets your requirements.  I decode the track and downmix using my preferred settings, but you can bitstream if necessary.

If you are remuxing, you can use eac3to to strip the dialnorm and see if you like the result better.  (As I'm sure you know, it's not necessary to convert the track to WAV to do that.)  When I remux, I often downmix multi-channel AC-3 to 2.0 PCM so that it sounds the way that I want regardless of playback device.  Like you, I far prefer the way audio sounds with VLC (which, in my case, is probably because it downmixes differently), so that was my playback method of choice before I discovered AC3Filter.

[dwalkerdon]

How do you guys deal with this? Do you all have Dolby Decoders and use bitstreaming or play directly via Blu Ray players? And if so, how do you know your players aren't doing the same thing?

do you use HDMI, Coax/Optical, or just the native directsound on the soundcard when watching movies?

I have a Onkyo TX-SR606 amplifier that doesn't seem to apply dialnorm to AC3 sources when it is being bitstreamed or transcoded and played using VLC and Media Player classic Via HDMI (but set-top DVD players apply the Dialnorm) 


if you can recall my comments on previous postings about how when i converted AC3 2.0 stereo sources to FLAC/WAV that they sounded better because the Dialnorm has been stripped, I got a lot of backlash because other members thought I was bs'ing but apparently i'm not the only one that recognizes the Dialnorm issue.

Just the other day, I converted a Mariah Carey #1's DVD AC3 5.1 track to FLAC using foobar2000, and it sounded just as good as the FLAC 2.0 track (the Rip that I downloaded had a 2.0 track was converted to flac from PCM)

[dwalkerdon]

So all in all, I don't currently see any good way to properly play AC-3 on a computer without transcoding it by hand. Of course this is no justification to distribute bloated FLACs instead of the raw AC-3, but it does create a real problem at least for playback purposes.

I always convert AC3 tracks to OPUS 5.1 whenever i archive rips on Hard Drives or Blu-Ray Data Discs. AAC also sounds really good (depends on which encoder you use though)

[Chewtobacca]

if you can recall my comments on previous postings about how when i converted AC3 2.0 stereo sources to FLAC/WAV that they sounded better because the Dialnorm has been stripped, I got a lot of backlash because other members thought I was bs'ing but apparently i'm not the only one that recognizes the Dialnorm issue.

No, you received "backlash" because you posted more or less the same comment in multiple threads and it got old fast.

[dwalkerdon]

No, you received "backlash" because you posted more or less the same comment in multiple threads and it got old fast.

yeah I was pretty annoying!

[deleted user]

For processing an AC-3 track on the fly, I use AC3Filter in concert with MPC-HC.  (The former will pop up automatically when you play a video using the latter.)  Give it a shot and have a look at the settings to see if it meets your requirements.  I decode the track and downmix using my preferred settings, but you can bitstream if necessary.

If you are remuxing, you can use eac3to to strip the dialnorm and see if you like the result better.  (As I'm sure you know, it's not necessary to convert the track to WAV to do that.)  When I remux, I often downmix multi-channel AC-3 to 2.0 PCM so that it sounds the way that I want regardless of playback device.  Like you, I far prefer the way audio sounds with VLC (which, in my case, is probably because it downmixes differently), so that was my playback method of choice before I discovered AC3Filter.

I shall try that eac3to road, that would at least save some space. Didn't know a tool existed that actually did it, but it seems logical that it is possible.

How do you guys deal with this? Do you all have Dolby Decoders and use bitstreaming or play directly via Blu Ray players? And if so, how do you know your players aren't doing the same thing?

do you use HDMI, Coax/Optical, or just the native directsound on the soundcard when watching movies?

I have a Onkyo TX-SR606 amplifier that doesn't seem to apply dialnorm to AC3 sources when it is being bitstreamed or transcoded and played using VLC and Media Player classic Via HDMI (but set-top DVD players apply the Dialnorm) 


if you can recall my comments on previous postings about how when i converted AC3 2.0 stereo sources to FLAC/WAV that they sounded better because the Dialnorm has been stripped, I got a lot of backlash because other members thought I was bs'ing but apparently i'm not the only one that recognizes the Dialnorm issue.

Just the other day, I converted a Mariah Carey #1's DVD AC3 5.1 track to FLAC using foobar2000, and it sounded just as good as the FLAC 2.0 track (the Rip that I downloaded had a 2.0 track was converted to flac from PCM)

I play it using my soundcard, although I also use HeSuVi to convert a 5.1 output to a 2 channel headphone output on-the-fly.

Yes, I do remember your comments, but I nevertheless stand by what I said. Converting lossy to lossless (unless necessary for PAL->NTSC conversion or similar) is a waste of space. It's better to transfer a 600 MB file and then have everyone process it as they wish than to send a file twice that size. Plus, as Chewtobacca noted, perhaps there's a lossless way of stripping the DRC.

By the way, what exactly is the relationship between the terms DRC and Dialnorm?

[Chewtobacca]

Plus, as Chewtobacca noted, perhaps there's a lossless way of stripping the DRC.

No, I didn't note that.  I suggested that you might use eac3to to remove the Dialnorm and see if you like the result better.  It might be enough to satisfy you.  I don't know of a way to remove the DRC setting of an AC-3 track without re-encoding, but you might find that AC3Filter's settings give you enough control (upon playback) to meet your needs.

By the way, what exactly is the relationship between the terms DRC and Dialnorm?

They are two different things.  The latter applies attenuation across a track; in other words, it applies the same attenuation to high sounds as it does to low.  (The idea is that you don't have to adjust the volume between, for example, one television show and another.)  The former applies different attenuation to high sounds and low sounds.  (The idea is that there is less variation in volume in the course of a track and therefore no need to reach for your remote.)  Both might be contributing factors to the fact that you find tracks "underwhelming".  Experiment with both eac3to and AC3Filter and see.

[deleted user]

Plus, as Chewtobacca noted, perhaps there's a lossless way of stripping the DRC.

No, I didn't note that.  I suggested that you might use eac3to to remove the Dialnorm and see if you like the result better.  It might be enough to satisfy you.  I don't know of a way to remove the DRC setting of an AC-3 track without re-encoding, but you might find that AC3Filter's settings give you enough control (upon playback) to meet your needs.

By the way, what exactly is the relationship between the terms DRC and Dialnorm?

They are two different things.  The latter applies attenuation across a track; in other words, it applies the same attenuation to high sounds as it does to low.  (The idea is that you don't have to adjust the volume between, for example, one television show and another.)  The former applies different attenuation to high sounds and low sounds.  (The idea is that there is less variation in volume in the course of a track and therefore no need to reach for your remote.)  Both might be contributing factors to the fact that you find tracks "underwhelming".  Experiment with both eac3to and AC3Filter and see.

Ah I see, thanks for the clarification.

[Doctor M]

I'm a bit confused.

If you use MPC-HC, then why don't you just turn off the DRC there?
The default internal AC3 filter is LAV. While playing your video, select the Play menu, filters, LAV Audio Decoder (internal).
Then on the first tab, the top option is Dynamic Range Compression. Uncheck it.

Similarly in VLC go to Tools/Preferences. At the bottom for 'Show Settings' select the 'All' button.
Then go to Audio/Filters and makes sure Dynamic Range Compressor is unchecked.

I wouldn't worry about dialog normalization, just turn up the volume. It was one of those good ideas that never did what it was supposed to.