Probable Codec problem. No audio on MPEG2 muxed files

[Kevlin]

Since yesterday some of my older .MPG files lack audio. Or at least in all programs but VLC which points to codec problems. I can't play the MPEG2 muxed audio but can still run the MPEG1 muxed ones.

I have the quicktime MPEG2 decoder so it should work. Have no idea what's have changes since last time a few weeks ago.

Anyone have any thoughts?

[Case]

This is a QuickTime issue. QuickTime Player won't output AC3 audio in muxed MPEG streams. It will let you hear audio in MPEG files if the audio is in MP2 or PCM format.
The QuickTime MPEG-2 Playback Component handles the video part only.

Try playback in MPEG Streamclip. You'll find that the developer found a way around this audio silence, despite the program's dependency on QuickTime.

Try playback in MPlayer. You'll find it works independent of QuickTime, just like VLC, and it will let you hear AC3 audio.

[Herve]

…and the last version of quickTime (and/or 10.6.3) has a bug with mpeg audios (if it managed to "display" audio before, it maybe don't works anymore)

You have to replace the new "QuickTimeMPEG.component" (located in "/System/Library/QuickTime/") with a previous one (from a backup?)
PS: funniest thing: it's a random behavior, not every users have this concern !

bye

[Kevlin]

Sitting down to try to resolve the issues with audio and have tried the folowing so far:
- Replacing the quicktimeMPEG.component doesn't work. still no audio.
- MPEG streamclips gives me no audio either. Only VLC gives me correct audio but I need to be able to edit the files so that program can't help me.

My old MPEG2 install file freeze at the end in the install phase when it says Running 'Packet script' (directly translated from swedish). It says 'less than one minute' but never finishes. And since it was several years since I bought it at apple store there isn't trace of that buy in my account history.

Anyone with more ideas? Need to resolve this issue before the weekend is over. Thanks for helping me out everyone.
/Kev

[Case]

You need to take the guesswork out by confirming the audio codec.
Check with VLC > Media Information > Codec details; or MediaInfo Mac; or VideoSpec

If it turns out to be DTS audio, then you have little choice but to try VLC's "Streaming/Export Wizard" (File menu), a sort of built-in conversion app. Not a very good conversion app, but the only one that handles DTS, as far as I know.

[Kevlin]

I used MediaInfo MAc and got this info:
Audio Stream Mode: CBR

I tried to replace my QuicktimeMPEG.component with a friends file but still no audio. So strange that one day it just stopped working. I have thought hard on what I might have installed that did something with the codec but I can't think of anything. Only thing I have installed is new iWork but I don't thinkit messed with the codecs would it?

I have the same problem once before but I just reinstalled the MPEG2 packet and it started to work again. Now I dont have that option anymore since the file is either corrupted or not working under snow leopard.

/Kev

[Herve]

Audio Stream Mode: CBR

and the ohers infos are… ? (this one is useless )

Now I dont have that option anymore since the file is either corrupted or not working under snow leopard.

go to apple site, access to your account, you will find ytour previous purchase, you could download (without fee) the last version of the mpeg2codec (maybe your is too old and outdated)

bye

[Kevlin]

Complete report from MediaInfo is this:
General / Container Stream # 1
Total Video Streams for this File -> 1
Total Audio Streams for this File -> 1
Video Codecs Used -> MPEG-2 Video
Audio Codecs Used -> MPEG-1 Audio layer 2
File Format -> MPEG-PS
Play Time -> 3mn 31s
Total File Size -> 70.5 MiB
Total Stream BitRate -> 2 792 Kbps
Video Stream # 1
Codec (Human Name) -> MPEG Video
Codec Profile -> Main@Main
Frame Width -> 480 pixels
Frame Height -> 576 pixels
Frame Rate -> 25.000 fps
Total Frames -> 5293
Display Aspect Ratio -> 4/3
Colorimetry -> 4:2:0
QF (like Gordian Knot) -> 0.360
Codec Settings (Matrix) -> Default
Video Stream Length -> 3mn 31s 720ms
Video Stream BitRate -> 2 489 Kbps
Video Stream BitRate (Nominal) -> 3 352 Kbps
Video Stream BitRate Mode -> VBR
Video Stream Size -> 62.8 MiB (89%)
Audio Stream # 1
Codec -> MPEG Audio
Audio Stream Length -> 3mn 31s 704ms
Audio Stream BitRate -> 192 Kbps
Audio Stream BitRate Mode -> CBR
Number of Audio Channels -> 2
Sampling Rate -> 48.0 KHz
Bit Depth -> 16 bits
Audio Stream Delay -> 648ms
Audio Stream Size -> 4.85 MiB (7%)

[aedipuss]

looks like a badly made svcd. the audio is the wrong rate. it should be 44.1khz.

[Kevlin]

I collect music videos and back in the day there wasn't much of a standard among them. I have over 20.000 videos and a few thousand of them have the same problem all of a sudden. Would be a shame if I had to go back to my old PC to edit the files I need and move them back to the mac. Would feel like a failure.

[aedipuss]

they should still play on the computer, just not in a standalone dvd player. do you have an MPEG-1 Audio layer 2 codec installed? for most windows versions it's part of it's included quartz.dll and nothing else is required. it's possible you have installed other codecs that are conflicting.

[Kevlin]

I can play them in VLC but not in any quicktime dependent programs like MPEG streamclip. Problem is that I need to be able to edit them for the quizes that I make. I know I could probably do it in windows like the good old days but I would rather solve the problem I have than move back to an older platform and admit defeat.

The problem I'm experiencing now is on the snow leopard mac not on a windows compluter.

[aedipuss]

try installing perian.
http://perian.org/

[Case]

The problem I'm experiencing now is on the snow leopard mac

"MPEG Streamclip news:
2010-04-08 (08/04/2010): MPEG Streamclip 1.9.3b3 beta, again compatible with YouTube, fixes the MPEG sound problem in Mac OS X 10.6.3 and QuickTime 7.6.6."

[Kevlin]

I think I love you guys. thanks for the input everyone. Embarrassing that it was such a simple solution you all saved my day.