Unrecognized MP2 codec? *Solved*

[omnikai]

I've been wrestling with the audio from my WinTV-PVR150 card for almost a year now. I've been recording old home videos for my parents via component cables and using the official WinTV V6 application and thus the default audio/video codec.

But my videos are exhibiting the weirdest of audio problems. Most commonly, no editing/encoding program will be able to render the audio. AVIDemux, which is a favourite of mine, will open the video without error, but will export the video without any audio. There is still an audio track, but it's been zeroed. VirtualDub refuses to touch the audio at all. SoundForge and Goldwave similarly refuse to open the .mpeg file. Nero Vision will encode the video, but the audio track will be lost.

GSpot claims that the Nero Audio Decoder should be able to decode the audio, but when tested within GSpot, no audio is produced.

The only thing that will play the audio of the mpeg file is Media Player Classic! Unfortunately I can't export the audio from MPC.

The file's too large for me to host, but here's the info I have from GSpot:

- Screenshot of GSpot window after analysis (http://www.rendreality.com/example.jpg)
- TXT list of all audio codecs installed on my machine according to GSpot (http://www.rendreality.com/codecs.txt)
- TXT of info relating to the Nero Audio Decoder, which GSpot says should play the audio (though oddly isn't included in the full codec list above) (http://www.rendreality.com/nero_codec.txt)
- The GSpot exported report for the file (http://www.rendreality.com/gspot_export.txt)


Pretty please give me a hand! I've been trying to sort out this ludicrously non-standard codec issue for a very long time. The weirdest part is that other captures I've done in the past turn out fine, and can be recoded with audio in AVIDemux. But whole batches of captures won't work, even though GSpot reports them to be using the exact same codecs as the working batches.

Edit: Sorry, posted wrong GSpot information. Give me one sec.

[omnikai]

Links updated, all info is now accurate.

[omnikai]

Further info:

I tried Audacity. It attempted to open the file, but reported an insanely long estimated time to decode it. See screenshot: http://www.rendreality.com/audacity_example.jpg

Also, here is my dxdiag, if my syspecs are relevant. http://www.rendreality.com/dxdiag.txt

Thanks in advance for any assistance!

[poisondeathray]

Are you saying the audio used to be rendered properly from your PVR output with the same applications (like avidemux), but for reason now it isn't?

Try opening with virtualdubmod.

If you just want to encode the .mp2 audio to something else, demux the audio and try besweet/belight.

There is also the possibility that the files are corrupted

[omnikai]

Thanks for the response PDR!

1) Yes, that appears to be the case. I usually do capturing in batches of tapes. So I have four .mpg files from three or so months ago, and four other .mpg files that I've captured just last month. This isn't the first time I've come across this problem. In that past I've been able to recode the audio with SoundForge, but with this latest batch SoundForge won't open the .mpgs at all anymore.

2) VirtualDubMod reports the error "Error decoding MPEG audio frame 0 (0:00): internal error" when I try to play back the .mpg file once it's been imported/indexed.

3) Besweet can not open the .mpg files (Using BeSweetGUI, the files didn't show up to be selected)

4) I don't believe the files could be corrupted, as the issue is consistent. Unless by some crazy coincidence the corruption *always* occurs on the audio track and only on certain .mpg files. Additionally, I would think MPC couldn't play it if they were corrupt.

I often reformat my machine, which may have contributed to different batches behaving differently. Nevertheless, these .mpgs are obviously encoded in an audio format that my computer can decode, as I can play the videos in MPC. So if MPC can read them, why can't *any* other program I try?

The "Properties" of the .mpgs list the audio codec as simply [Audio: MPEG Audio 44100Hz mono 224Kbps [Audio]].

[Midzuki]

ominikai wrote:

GSpot claims that the Nero Audio Decoder should be able to decode the audio, but when tested within GSpot, no audio is produced.

I guess that Nero is causing a codec hell on your system.

[Soopafresh]

I'm probably wrong, but I think there's a bug in the way Mpeg files are produced with that card. It puts the audio on a different mux "channel", so most software isn't able to find it. The question is, what does one do now?

[omnikai]

Can you explain that further Midzuki? What would cause that, and what could I do to fix it? Nero Vision is part of my workflow, I can't really install/uninstall it every time I need other codecs to work @_@

[omnikai]

That would certainly explain a lot, Soopafresh. But yes, what can one do to fix it?

[poisondeathray]

You might have to demux the audio first before using belight

Seems like a crapshoot, but it wouldn't hurt to try mpegstreamclip

If MPC can play it, you might be able to use an avisynth script (with audio=true), using directshowsource to open it in vdub

If none of these work, post a small sample clip and maybe someone here will be able to figure out a solution

Good luck

[omnikai]

I'll try mpegsteamclip. Unfortunately belight does not work, I click "Start" to export to an .mp3 and I see a command prompt box open for a split-second, and then nothing.

I don't think I'm knowledgeable enough to use avisynth scripts (one day I'll have to learn). Also, I can't post a clip because the files are 4gb (1hr long). No programs will open them to let me export a clip, so I can't host something small enough for download.

*sigh* Looks like I may have to recapture these tapes and hope I just get luckier next time.

But for the future, how can I avoid these potential codec conflicts? Next time I reformat I'll install nothing but Xvid, the WinTV app/drivers, and Nero Vision. That might limit incompatibilities that K-Lite of XP Mega Pack might have introduced.

Thanks for the advice everyone!

[Soopafresh]

It's a little weird that your audio is mono MP2 at 44.1Khz - makes it more work to get it DVD compatible.

Can you play this file? This is stereo Mp2 at 48Khz

clip.mpg

[omnikai]

Yes, both MPC and AVIDemux can open/playback that file with perfect audio.

The reason I set it to mono for capture is because the video camera I use to capture from only has one audio jack, so I only get audio on the left channel. So I mix it back to mono.

I tried MpegStreamClip. The file opened alright, but only played back silence. It gave me an error saying I didn't have the quicktime mpeg-2 decoder installed though. I installed the latest Quicktime Alternative codec.

[omnikai]

*Gasp* I think I just figured it out. Soopa's question about mono sound made me wonder about my capture settings. Like I said, I set it to mono because the sound only comes in one channel.

I set it to stereo and captured it, and it works fine! AVIDemux picks up the audio properly and can export it.

So for some reason capturing in mono causes the WinTV-PVR150 to encode the audio to some weird stream that can't be detected by most programs!

Thanks so much everyone! I'm so glad to finally have this dealt with! I still need to recapture all that footage, but at least I know it'll work this time!

[Soopafresh]

I don't know the capturing software at all, but can you try capturing to stereo and 48,000hz sample rate if the choice is there?

Edit - You beat me to the punch. Glad it worked for you

[poisondeathray]

Open up graphedit => render media file (since you mentioned you have k-lite installed already, graphedit comes with it under tools). This should tell you what filters are being used in mpc to render the file.

It might be that gspot is reading the file incorrectly. Try mediainfo and select view=>text

mpg2cut2 should be able to cut off a small clip. You can also demux to elementary streams with this.

[poisondeathray]

Nice!

[omnikai]

Thanks for the suggestion PDR.

And thanks again everyone!