Lower audio sample rate in an mkv?

[Arttworx]

I have some mkv files in which the audio plays too fast, so i'd like to change the sample rate to 44.1 from 48k so it will play the audio slightly slower. The audio currently is playing at a faster pitch, literally sped up, eventually playing ahead of the video if played for long enough. So i'd rather have it slow it down also changing the pitch. Does anyone know of some software for windows that will just remux it or whatever to have the file play the audio slower? I don't need a "player" that will play it slower, I need the file itself to be changed.

I hope this makes sense. I barely know what the hell i'm talking about.

Thanks!

[Cornucopia]

Demux, change the header's SR, then remux with the video.

Scott

[Arttworx]

Wow. It's amazing how many words I can not know in such a small sentence!

But I think I get what you're suggesting, but is there a specific software you suggest that would do this quickly and easily (simple). Or somewhere that would explain it so an idiot could understand?

With what you're saying, by changing the SR (sample rate?) in the header, it's like tricking the video to think it's got a 44.1 audio sample rate when the actual file has it encoded at 48 so it will play it slower? Or am I way off?

Thanks for the response!!

[El Heggunte]

Hmmm, that sync issue can be more complicated than you think. First, how do you know that 44.1kHz should be the correct playback rate Besides, since you're dealing with Matroska files, it's possible that they contain variable~framerate video, which only makes the problem worse.

Please post at least a Mediainfo report about one of those pesky MKVs.
Without some more info, it's quite improbable someone will be able to help you.

[jman98]

Changing the sampling rate will NOT make ANY changes to the speed or time of the audio file. Try it and see if you don't believe me.

The only way I know to deal with speed issues is to use Cool Edit (commercial product) as it has a feature that can handle this. Audacity is free and it might also be able to do it.

[Cornucopia]

Changing the sample rate as in "Sample Rate conversion" which is a form of resampling will NOT make any changes to speed/time/pitch, but changing the header that describes EXISTING sampled audio as having a different (than original) sample rate WILL. Try and see if you don't believe me. This is similar in functionality to Virtualdub's [FrameRate | Source Rate Adjustment] tool for video.

Most changes to headers require a hex editor, though there may be a dedicated audiofile tool out there.

Scott