VDub-MPEG2 doesn't open MPEG-2 files any longer

[LoRd_MuldeR]

Hi.

Suddenly VirtualDub-MPEG2 refuses to open MPEG-2 files. Even files I had opened before without problem! It opens and parses the MEPG-2 file. But then it says "No audio decompressor could be found to decompress the source audio format" each time I click the play button or I try to start the conversion. What's wrong? I did not change anything...

Do I need to install a MPEG-2 audio decoder? Maybe some ACM codec?
This was never neccessary before and yesterday everything was okay. Strange...

Thanks for reply

[setarip_old]

Hi!

If your O/S is WinXP, perhaps the simplest solution would be to perform a "System Restore" back to the last time things were working properly.

Otherwise, it sounds like you've either corrupted or possibly inadvertently turned off an audio codec...

[LoRd_MuldeR]

I don't have "System Restore" enabled.

What audio codec is needed? I never needed to install any audio codec to get this working and yesterday it sill worked fine. I did not do anything which could have removed/disabled any audio-codec until then. If any codec is needed by VDub-MPEG2 to decompress MPEG-2 audio, it must ship with Windows. I never installed something like that manually...

I already googled for "MPEG-2 audio ACM codec", but no results...

[setarip_old]

1) Do you have FFDShow installed?
2) Do the files possibly contain .AC3 audio?

[LoRd_MuldeR]

1) Do you have FFDShow installed?
2) Do the files possibly contain .AC3 audio?

1. I have ffdshow installed. But I don't think ffdshow's audio-decoder has got an ACM interface. So, in contrast to ffdshow's video decoder, I don't think I can use ffshow to decode audio in VirtualDub.

2. Nope. It's MPEG-2 video files captured from TV. Audio stream is "normal" MPEG Audio Layer-2. I had tons of files with that audio format and they opened properly in VDub-MPEG2.

[fccHandler]

In VirtualDub-MPEG2, go into Options / Preferences / MPEG, and make sure that "Allow Direct Stream Copy of MPEG audio" is unchecked.

[LoRd_MuldeR]

In VirtualDub-MPEG2, go into Options / Preferences / MPEG, and make sure that "Allow Direct Stream Copy of MPEG audio" is unchecked.

Yeah, that was the problem! Thanks, fccHandler !!! :D
You REALLY should add a warning for that option!

[setarip_old]

@Lord_Mulder

Glad to see that "fccHandler" had the answer to your problem!I did not do anything which could have removed/disabled any audio-codec until then.But you apparently did do something to change a setting afterall ;>}

[LoRd_MuldeR]

@Lord_Mulder

Glad to see that "fccHandler" had the answer to your problem!But you apparently did do something to change a setting afterall ;>}

Who could have known that a setting called "Allow direct stream copy of MEPG-Audio" will completely disable MPEG-Audio decoding, even when *NOT* in "direct stream-copy" mode ^^

I think there should be a warning for that in VDub-MPEG2 :rolleyes:

[setarip_old]

I agree wholeheartedly ;>}

[fccHandler]

That option has a long history of confusing people... It was originally "hidden" in the extended open options dialog for MPEG files. It defaulted to unchecked, and you had to check it for each and every MPEG if you wanted to use it. By someone's request, I recently moved it to the Preferences dialog and made it remember its setting.

Because of the way the MPEG module is structured, MPEG audio and video are always decompressed before being sent through the rest of VirtualDub's pipeline. Unfortunately, this design makes Direct Stream Copy of MPEG audio and video impossible. My checkbox is a dirty kludge to get around that, at least for audio.

What the checkbox really does is it makes the MPEG audio parser behave exactly like the AVI and ASF audio parsers, both of which require external ACM codecs to decompress their audio streams. In theory, if you've installed an ACM codec for MPEG Layer II, then you shouldn't receive an error with the box checked.

I think what we need here is a more helpful error message. ;)