BeSweet transcoding Extremely Sloooooow!

[storebror]

Hi. I'm off to transcode an audiofile into PCM-WAV from framerate 24044(?!:confused: )to 23976 with BeSweet but the transcodingprocedure is extremely slow, eg. 10min/in an hour....anyone knows why and what to do about it?
Thx.

[mrslacker]

Originally posted by storebror
Hi. I'm off to transcode an audiofile into PCM-WAV from framerate 24044(?!:confused: )to 23976 with BeSweet but the transcodingprocedure is extremely slow, eg. 10min/in an hour....anyone knows why and what to do about it?
Thx.

I'm not a regular to this forum, but I'll suggest two things anyway:
1. try using the soundtouch routines to do the time scale modification - beta besweet only?
2. try wsola from sourceforge, it uses a fast fft implementation - search for mffm at sourceforge

Although, you might be better off with a ChangeFPS(23.976,true) or AssumeFPS(23.976) if your getting this from an avi or something.

[niamh]

Could be you transcode from a HD on USB 1 or the like?

[storebror]

Originally posted by mrslacker

Although, you might be better off with a ChangeFPS(23.976,true) or AssumeFPS(23.976) if your getting this from an avi or something.

But these commmands only applies to AviSynth? And how do you transcode soundfiles in AviSynth? As far as i l know it's impossible.

[mrslacker]

storebror,

I think you may have misquoted me a bit. :)

Actually, I'd do something like this if i were determined to avoid decimating frames and thus wanted change the playback speed of the video:
AssumeFPS(23.976,true)
ResampleAudio(desiredrate)
or
AssumeFPS(23.976,true)
SSRC(desiredrate)

When AssumeFPS syncs the audio, it just changes the sample rate. It doesn't resample - it changes the sample rate. The resample command will get it back to a standard sample rate. Of course, the AssumeFPS method intruduces pitch changes, although very small with your 24044 -> 23976 conversion.

Using ChangesFPS instead should keep the playback length the same and make your audio processing easier, but it will chop frames on your way down to film.

If you are brave, you could try using TimeStretch(...) to preserve pitch. Its coded from SoundTouch (used in BeSweet).

Load the script in VirtualDub or the like, and extract the raw audio. Then, encode!

Why was the framerate of your source so screwy to begin with? Corrupt source? Chopped frames? That would be my guess. That's why I'd use ChangeFPS, to keep the overall original playback speed.

[niamh]

Hmmm,I was under the impression storebror said besweet transcoded 10 minutes worth of audio in a full hour, rather than saying that the length/pitch of file was wrong... anyway,I'll leave you to it, cause it seems I'm way off ;)

[storebror]

How does one load it into Vdub? Loading the .avs-script like an AVI right?

[storebror]

[QUOTE]Originally posted by niamh
..Hehe, forgot to add that blooper as well:D ..

[storebror]

[QUOTE]Originally posted by mrslacker


HEEEEYYYYYY!!!! Thx a lot for the "Tip of the Year", so far:D I managed to get a Perfect result thanks to your scripthints! Just created the assumeFPS-script and loaded it into Vdub and, Magic:=) I'll use this all the time.

[mrslacker]

Originally posted by niamh
Hmmm,I was under the impression storebror said besweet transcoded 10 minutes worth of audio in a full hour, rather than saying that the length/pitch of file was wrong... anyway,I'll leave you to it, cause it seems I'm way off ;)

It's transcoding slowly because of the time scale modification. I assumed he's doing this with the standard "-ota" frame rate modification settings. Finding a faster method involves tackling the task of effective time stretching of the audio or just resampling for speed.

Your not way off - your right on the money, you just didn't understand what the issue was.

[mrslacker]

Originally posted by storebror
HEEEEYYYYYY!!!! Thx a lot for the "Tip of the Year", so far:D I managed to get a Perfect result thanks to your scripthints! Just created the assumeFPS-script and loaded it into Vdub and, Magic:=) I'll use this all the time.
Really? That good? So, I noticed that VirtualDub likes to crap out occasionally when extracting audio. You might need to try 1.6.1 or Mod to get it to work with less than perfect sources. Why not used ChangeFPS instead? It would only drop four frames per minute with your conversion and you could leave the audio alone. I'm assuming you are reencoding to mpeg or something. If not, nevermind.

Any chance of editing that quote a few posts back? It reads really weird. Thanks and good luck.