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Question: My AC3 Codec is not working. Help!

Hello,


I have Perian as my AC3 Dolby Codec and it was working fine until I upgraded to Mountain Lion. Does anyone have advice on what can be done? It seems as if there arent any Dolby AC3 codecs compatible with Mountain Lion. If anyone can help, I greatly appreciate it.


Thanks!

MacBook, Mac OS X (10.7.3)

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Got it, thanks!


Don't give up on DivX -- it's just a matter of getting the right codecs (like the updated a52AC3 and Perian) and don't automatically believe, as the a52 codec page tells you, that you have to ditch Quicktime's DivX codecs. In MY case, I needed them, which I found out by moving the QT DivX codecs to a folder on an external drive, restarting, and then trying to get DivX to work. DivX would NOT work for me without the Quicktime DivX codecs back in their correct folders.


f you use Firefox for a browser, go to Tools > Add-Ons > Extensions, and disable the DivX Plus Web Player HTML5 add-on. Safari and Chrome should work without fiddling about with THEIR extensions or add-ons at all.


Good luck, and thanks again!


Bart

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Oct 4, 2013 4:05 PM in response to William Stanton In response to William Stanton

wow, you still don't get it?


1. Launch "Audio MIDI Setup" App

2. Verify channels are set correctly

3. Close "Audio MIDI Setup"

4. Launch "System Preferences"

5. Click on "Sound"

6. Test speaker channels with balance slider

7. Channels are reversed…

I honestly don't know how to explain things any more simply. Will, therefore, go through your list and, for the benefit of other users not already familiar with this process, make some additional amplifying comments of my own.


1. Launch "Audio MIDI Setup" App

I totally agree. The first step is to ensure your system hardware is properly configured.


2. Verify chennels are set correctly

Not really sure what you want people to do here. What I recommed is that people check to ensure their speakers are wired correctly. To do this, press the press the "Configure Speakers..." button under the "Output" tab. When the new window opens, press the "left front" and "right front" buttons under the "Stereo" tab to generate white noise audio signals and observe through which speaker the noises are played back. If you are in the default configuration mode (left front = Channel 1 and right front = Channel 2) then pressing the "left front" button will send sound to your left speaker and pressing the "right front" button will send sound to your right speker. If it doesn't, then your speakers are reverse wired and you really should change their wiring. In this configuration your system should match the configuration of all other users running the default configuration, all properly encoded files (Left channel source audio input recorded to Stereo Channel 1 and Right channel source audio input recorded to Stereo Channel 2) will play correctly in all media applications, and the System Preferences > Sound > Output Blalance slider will work normally. If, on the other hand, you have a large number of files encoded improperly (Right channel source audio input recorded to Stereo Channel 1 and Left channel source audio input recorded to Stereo Channel 2) and opt to reverse your MIDI speaker configuration, then be aware of the following: while all incorrectly recorded files played in non-QT 7 media apps (e.g., VLC, QT X, iMovie, GarageBand, iTunes, etc.) will ignore any embedded QT 7 channel assignments and play correctly, all properly encoded files will play with Left-Right channels reversed, the System Preferences > Sound > Output Blalance slider action will be reversed, any files played in QT 7 apps (QT 7, QT 7 Pro, MPEG Streamclip, etc.) will ignore your MIDI app settings and play the file content according to their embedded chennel assignments, your system configuration will not match that of most other users and most files shared to other systems or devices will play differently on those systems and devices than they do on your system. In any case, no matter how you opt to configure the MIDI Setup app, press the "Apply" button if not grayed out to apply any changed settings to your system before pressing the "Done" button to close the "Configure Speakers..." window.


3. Close "Audio Midi Setup"

Nothing to add here.


4. Launch "System Preferences"

No problem with this either.


5. Click on "Sound"

Go for it.


6. Test speaker channels with balance slider

Okay, here is where I ran into some problems. First of all, whether or not you have a "balance slider" to play with actually depends on how your speakers are connected to your system. In my case, I was using the optical output to connect to a Logitech digital decoder-amplifier-speaker hardware complement and this device has no device control options. So it was quite a while until I finally figured out that I had to disconnect the cable from my system to allow the system to enable the internally built-in speakers before I was able to access a "balance slider" and duplicate your stated workflow. This is also where I discovered that it is the Audio MIDI Setup app that was controlling the slider action. Basically, Apple's labeling of the slider leaves something to be desired since the Left/Right labels are, in this case, relative to the Audio MIDI Setup app channel preferences. In the default configuration, the slider action is normal with the "Left" label representing Stereo Channel 1 audio and "Right" label representing Stereo Channel 2 audio. Thus, when you reverse the Audio MIDI Setup app's speaker configuration preference, you are also reversing the slider action with respect to the Left-Right labels.


7. Channels are reverse...

Based on this comment, I suspect that when you said you were confirming that channels are set correctly, what you really meant was that you were confiming the channels were set correctly relative to a file being played back at the time and not set correctly based on an absolute harware generated signal reference. If true, then I further suspect that your Audio MIDI Setup app speaker configuration looks like this


User uploaded file


rather than this


User uploaded file


which would explain why your balance slider action is reversed.



And no offense but only long-time Mac users will get the email joke ;P

No offense taken, However, I might point out that my original DotMac, now defunct MobileMe, and current iCloud account email addresses all remain valid. (I.e., the Apple mail server still redirects email using older addresses to me so I don't see a problem.)



Please do those seven steps on your Mac first. I'm afraid if you don't understand that part, you'll never be able to help me…

As noted above, I have performed the steps you listed. My system hardware (in terms of reference signal generation) is correct, my speakers are connected correctly, I am running the default Audio MIDI Setup Speaker Configuration which matches nearly all other systems in use, the external speaker interface is delivering 1 to 6 channels of audio as encoded from the original source inputs, and my stereo playback is correct as recorded and/or "hard" cross-coded. The only issue I might complain about is the fact that only the QT 7 and MPEG Streamclip media players support QT 7 Pro "software" channel assignments—but since QT 7 is my primary player, this is not really an issue. Lastly, I do not suffer your System Preferences > Sound reversed "balance slider" issue. Rather than debating my understanding (or lack thereof) of your problems, let's try a simple experiment....


http://downloads.walker4.me/downloads/Temporary_files/DVD-Audio%20Test%20Norm.mo v


The above URL points to an MOV file containing H.264/AAC content. I know the file is correctly hard encoded for correct playback in any media player capable of handling this file type and compression formats. If the file plays correctly on your system, then it is properly configured. If it does not play correctly, then your system is either incorrectly configured or you have a system malfunction. By "play correctly" I mean that the speaker playback display references should match the actual Left/Right speaker playback channels. Feel free to download and test the file in anay and all media players installed on your system. It even plays correctly in my system's browser plug-in player.


What are your playback results?


User uploaded file

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Jul 31, 2012 5:35 AM in response to JSBillian In response to JSBillian

why do you use AC3 files, are you authoring DVD?


If you have an authoring application or an encoding application on your Mac, you will have an AC3 codec on your machine.


The Apple AC3 codec used with Compressor and DVDS Pro works fine in ML

Jul 31, 2012 5:35 AM

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Jul 31, 2012 7:23 AM in response to JSBillian In response to JSBillian

I have the same problem, I tried to open some avi movies and there's no sound since I've installed ML... I read that Perian will stop developing updates so I think this problem will continue unless apple provides a codec for quicktime playing avi files with sound...

Jul 31, 2012 7:23 AM

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Jul 31, 2012 7:52 AM in response to JSBillian In response to JSBillian

I have Perian as my AC3 Dolby Codec and it was working fine until I upgraded to Mountain Lion. Does anyone have advice on what can be done? It seems as if there arent any Dolby AC3 codecs compatible with Mountain Lion. If anyone can help, I greatly appreciate it.

Can you be more specific regarding your problem? Which player are you using? What kind of files/content are you trying to play? Are trying a passthrough of the AC3 5.1 data or play it as "mixdown" stereo, DD PL, or DD PL II audio?


On my Mountain Lion system I am assuming the QT X player is still using QT X native AC3 playback support while the QT 7 Player is still using Perian AC3 playback support. However, I had noted the following items of possible interest for my H.264/AAC/AC3 files in M4V file containers:


1) The QT X Player appears to list the "English" Language tracks in their proper order (AAC followed by AC3) and I am able to switch between tracks using the View menu "Language" option but the "Inspector" window does not update reflecting the change.


2) The QT 7 Player seems to list the "English" Language tracks in their reverse order (AC3 followed by AAC) and I am unable to switch between tracks using the View menu "Language" option. However, I can switch between the Language tracks manually using the "Properties" window and the "Inspector" window is immediately updated to reflect the audio track compression format being played.


3) The AC3 DD5.1 default (L C R Ls Rs LFE) speaker assignment for my M4V files appears to play correctly in both the QT X and QT 7 players.


4) An AC3 audio file containing AC3 DD5.1 default (L C R Ls Rs LFE) speaker assighment only appears to play correctly in the QT X Player.


5) An AC3 audio file containing AC3 DD5.1 Perian recommended (L R C LFE Ls Rs) speaker assignment only appears to play correctly in the QT 7 Player.


6) The QT X player will only open/play an AC3 audio file in an AC3 file container while the QT 7 Player will open/play an AC3 audio file in either an AC3 or MOV file container.


7) Not sure if this is new or not, but I changed the extension on a VOB file containing AC3 DD5.1 English, AC3 stereo Spanish, and AC3 stereo French audio to an MPEG extension and the file plays the video and all three audio tracks simultaneously but QT 7, as is normal, recognized none of the "muxed" AC3 audio streams. (Don't normally keep multiple language VOB files on my system so I don't know if this is different from Lion OS.)


User uploaded file

Jul 31, 2012 7:52 AM

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Jul 31, 2012 9:05 AM in response to Jon Walker In response to Jon Walker

Hi Jon, thank you for answering.

I'm trying to use both QT7 and QTX but both plays avi file without sound.

Here's an info for the avi file:


General

Complete name : /Users/MARCO/Desktop/Filmes/Extremely.Loud.Incredibly.Close.DVDRip.XviD-NeDiVx CD1.avi

Format : AVI

Format/Info : Audio Video Interleave

File size : 699 MiB

Duration : 1h 5mn

Overall bit rate : 1 496 Kbps

Writing application : VirtualDubMod 1.5.10.2 (build 2540/release)

Writing library : VirtualDubMod build 2540/release


Video

ID : 0

Format : MPEG-4 Visual

Format profile : Advanced Simple@L5

Format settings, BVOP : 2

Format settings, QPel : No

Format settings, GMC : No warppoints

Format settings, Matrix : Default (MPEG)

Muxing mode : Packed bitstream

Codec ID : XVID

Codec ID/Hint : XviD

Duration : 1h 5mn

Bit rate : 1 103 Kbps

Width : 640 pixels

Height : 272 pixels

Display aspect ratio : 2.35:1

Frame rate : 23.976 fps

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Progressive

Compression mode : Lossy

Bits/(Pixel*Frame) : 0.264

Stream size : 515 MiB (74%)

Writing library : XviD 64


Audio

ID : 1

Format : AC-3

Format/Info : Audio Coding 3

Mode extension : CM (complete main)

Codec ID : 2000

Duration : 1h 5mn

Bit rate mode : Constant

Bit rate : 384 Kbps

Channel(s) : 6 channels

Channel positions : Front: L C R, Side: L R, LFE

Sampling rate : 48.0 KHz

Bit depth : 16 bits

Compression mode : Lossy

Stream size : 179 MiB (26%)

Alignment : Split accross interleaves

Interleave, duration : 42 ms (1.00 video frame)

Interleave, preload duration : 500 ms


I also have another file but the problem is not the same.

I can play it with QT7 (I have sound) but I can't even open on QTX, video doesn't start...

Here's the info:


General

Complete name : /Users/MARCO/Desktop/Filmes/Trishna - BRRip - XviD - 1CDRip - [DDR].avi

Format : AVI

Format/Info : Audio Video Interleave

File size : 698 MiB

Duration : 1h 53mn

Overall bit rate : 862 Kbps

Writing application : VirtualDubMod 1.5.10.2 (build 2540/release)

Writing library : VirtualDubMod build 2540/release


Video

ID : 0

Format : MPEG-4 Visual

Format profile : Advanced Simple@L5

Format settings, BVOP : 1

Format settings, QPel : No

Format settings, GMC : No warppoints

Format settings, Matrix : Custom

Codec ID : XVID

Codec ID/Hint : XviD

Duration : 1h 53mn

Bit rate : 768 Kbps

Width : 672 pixels

Height : 288 pixels

Display aspect ratio : 2.35:1

Frame rate : 24.000 fps

Color space : YUV

Chroma subsampling : 4:2:0

Bit depth : 8 bits

Scan type : Progressive

Compression mode : Lossy

Bits/(Pixel*Frame) : 0.165

Stream size : 621 MiB (89%)

Writing library : XviD 1.2.1 (UTC 2008-12-04)


Audio

ID : 1

Format : MPEG Audio

Format version : Version 1

Format profile : Layer 3

Mode : Joint stereo

Mode extension : MS Stereo

Codec ID : 55

Codec ID/Hint : MP3

Duration : 1h 53mn

Bit rate mode : Variable

Bit rate : 84.9 Kbps

Nominal bit rate : 90.0 Kbps

Channel(s) : 2 channels

Sampling rate : 32.0 KHz

Compression mode : Lossy

Stream size : 68.7 MiB (10%)

Alignment : Aligned on interleaves

Interleave, duration : 36 ms (0.86 video frame)

Interleave, preload duration : 526 ms

Writing library : LAME3.98r

Encoding settings : -m j -V 4 -q 2 -lowpass 15.1 --abr 90



I hope you can reach a conclusion with this information.


I just want to inform that when I try to open the first file on divx player I get the pop message saying that this file contains a track in the dolby ac3 codec (code 8192) format. I need to install QT component.


I presume it's because perian needs to update the ac3 codec...


Will wait for more conclusions...

Jul 31, 2012 9:05 AM

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Jul 31, 2012 11:42 AM in response to Marco9774 In response to Marco9774

Hi Jon, thank you for answering.

Was actually directing my response to the OP. However, ...



Here's an info for the avi file: ...

As I understand it you have an AVI file container with XviD/AC3 content which plays the video but no audio in both QT X and QT 7 players and a second AVI file container with XviD/MP3 content which plays audio and video in QT 7 but has an unspecified playvback problem using the QT X Player. (Assume you may not have audio using QT X Player.)


1) I don't use the AVI file type because it was replaced by Microsoft about 11 years ago and has not been officially supported since that time by its originator.


2) I don't know if the "DivX Player" you referred to above means that you have the DivX codec software also installed on your system or not. However, if true, then there is a possibility of a codec conflict problem on your system if the Perian codec component package is also simultaneously installed. In my case, I use the Perian package v1.2.3 to handle both XviD and DviX video content and have no DivX software installed. (But then my work flow is directed toward the use H.264/AAC/AC3 content in M4V file containers for maximum OS/IOS device compatibility.)


3) This Perian package (v1.2.3) also installed the v1.8 Core Audio A/52 and AC3 Codec Component in my "Audio/Plug-Ins/Component" folder which is what I assume is currently handlng QT 7 AC3 content if not both QT 7 and QT X.


4) Since the Perian codec component package runs in the 32-bit mode, I do not usually try to watch AVI content in the 64-bit QT X Player which seems less compatible with many AVI "legacy" codecs than the QT 7 Player.


5) Since you did not indicate if you had modified app handling of AC3 audio via "passthrough" to an external decoder, I do not know if you have been messing in your system with the Terminal app or not. In my case, the content is handled as DD Pro Logic II optical output to a decoder attached to my iMac (i.e., I did not make system chages which may or may not be compatible with any particular decoder) and as AC3 DD5.1 "Passthrough" output from all TV devices in my home while I let iTunes distribute the same file to iPhone, iPod, and iPad devices which themselves only support stereo but which can also Air Play 5.1 audio remotely through the TV devices.


At this point all I can say is that it seems I can play AC3 and AAC audio via both the QT X and QT 7 players on my Mountain Lion system but cannot confirm whether or not this is also true for XviD/AC3 and/or XviD/MP3 AVI content since these are not file formats I normally use. And when I do use AVI files, the content is normally compressed as DivX5/MP3 content. Further, I am still using the same Perian codec component support installed in July of last year so, at least for me, there does not seem to be a current need to update AC3 playback support. My recommendation at this point might be to remove/reinstall the Perian software in case the upgrade to Mountain Lion broke the connection between your players and codec components as happened for may users during the Leopard to Snow Leopard upgrade.


User uploaded file

Jul 31, 2012 11:42 AM

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Jul 31, 2012 3:11 PM in response to Jon Walker In response to Jon Walker

Hi Jon, sorry for the confusion. I've said thank you because you were the only person who brought some explanation to the post and I just wanted to be kind for that...


Now the codecs: I didn't change anything in the original install for the codecs mentioned. I've also tried to uninstall all them and just use Perian (same version as you 1.2.3), same problem, same situation for file 1 and 2. What I think is that quiacktime stop playing movies (avi files using ac3 codec) with sound with the ML upgrade as I've been using without problems with Lion and before with SL...


You should get a file like those and test for yourself, I understand you have no need for that and you'd probably waste your time but it'd be the only way to check what's happening.


Thank you for your time.


Best Regards,


Marco

Jul 31, 2012 3:11 PM

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Jul 31, 2012 3:26 PM in response to Marco9774 In response to Marco9774

You should get a file like those and test for yourself, I understand you have no need for that and you'd probably waste your time but it'd be the only way to check what's happening.

Agreed. Best approach would be to test a file (or short snippet thereof) known to not be working on your system. Do you have anything suitable available that can be posted or emailed?


User uploaded file

Jul 31, 2012 3:26 PM

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Jul 31, 2012 3:34 PM in response to Marco9774 In response to Marco9774

I'll try to get something, for now just have both movies about 650mb...

I'll inform if I can get a small file with same problems

You could try trimming a 10-30 second segment from start or end of your files and see if they have same playback problems. See my profile for email address.


User uploaded file

Jul 31, 2012 3:34 PM

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Jul 31, 2012 6:41 PM in response to Marco9774 In response to Marco9774

Hi Jon I have the short video prepared to send but I can't find your email on your profile.

File received. For the benefit of other readers, here is what I found. Test XviD/AC3 file played audio and video using QT 7, MPEG Streamclip, and VLC media players under Mountain Lion. QT X Player only played the video portion of the file data. Problem may be associated with the interpretion of the samling rate by the QT X Player which thinks the sampling rate is only 32.0 KHz instead of the more standard 48.0 KHz AC3 DD5.1 sampling rate. (I.e., both QT 7 and VLC read the file as having a 48.0 KHz sampling rate and MPEG Streamclip did not correctly indicate the AC3 codec and thought the sampling rate was 0.001 KHz but played the audio anyway. Not sure if the problem is in the file's audio data header (more likely since both QT X and MPEG Streamclip had problems reading it) or the QT X player itself. In any case, QT apps are very "standards based" and if the QT X Player considers the audio to have been encoded with what it considers non-standard settings, may simply refuse to try and play the audio data whether encoded correctly or not.


User uploaded file

Jul 31, 2012 6:41 PM

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Aug 13, 2012 1:39 PM in response to JSBillian In response to JSBillian

AC3 should still play under Mountain Lion in QT X so I'm assuming your problem is with QT 7 and file formats not supported by QT X.


For me this was happening with .mkv files containing AC3 audio played through QT 7 using Perian (which as I understand it is only getting one more release which may or may not fix this issue).


Thankfully like all things it's easy when you know how, this is what worked for me.


Download and extract the A52Codec.component file and replace the one in your Mac's /Library/Audio/Plug-Ins/Components/ directory with it.


Go to System Preferences > Perian and in the drop down box next to Audio Output: choose Multi-Channel Output, ignoring the warning which will be displayed.


Close System Preferences.


This fixed the problem for me in that I can now play my files (H.264 video & AC3 audio in the .mkv container) using QT7 and also export them with the video passed through as is and the audio transcoded to AAC for my Apple TV.


Hope this helps...

Aug 13, 2012 1:39 PM

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Aug 13, 2012 5:50 PM in response to JSBillian In response to JSBillian

I fixed this same problem on my laptop running Mountain Lion (10.8) by installing the "A52" Codec which appears to include support for AC3.


http://www.macupdate.com/app/mac/21875/a52codec


There are instructions once you load the .dmg (Read Me.rtf)


"Install:

Copy A52Codec.component into:

/Library/Audio/Plug-Ins/Components or ~/Library/Audio/Plug-Ins/Components

and copying AC3MovieImport.compontent into:

/Library/QuickTime or ~/Library/QuickTime

The A52Preferences application can change the prefs for the codec but is not necessary with version 1.0 or greater of Perian.

Be sure to remove any instances of AC3Codec in both /Library/QuickTime and ~/Library/QuickTime. It causes problems and is completely supplanted by this codec.

Aug 13, 2012 5:50 PM

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Aug 15, 2012 4:23 PM in response to R08 In response to R08

R08 wrote:


...


Thankfully like all things it's easy when you know how, this is what worked for me.


Download and extract the A52Codec.component file and replace the one in your Mac's /Library/Audio/Plug-Ins/Components/ directory with it.


...

Thank you. That fixed AC-3 playback on my Mountain Lion.


Where did you find that codec? It has the same version number (1.8) as the codec in Perian but the file is much smaller and has a more recent date (and it works with Mountain Lion).


I searched but found only versions older than Perian's.

Aug 15, 2012 4:23 PM

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User profile for user: JSBillian

Question: My AC3 Codec is not working. Help!