Audio track from 25fps video with a 23.976 fps video

[cedworld]

Hi!

I have a video with a 23.976 framerate, and an audio track from a DVD with a 25 fps.
of course, when i mux them, there is a desync...

so i would like to know how convert the audio track (ac3 5.1) losslessly
it appears to be the easiest thing to do here...

is that even possible to change the speed of the audio without complete conversion??

thanks for youy help

[jagabo]

If it's an AVI file and you don't care about DVD compatibility you can just change the frame rate in the header of the file. Then mux the audio and video together.

Changing the runtime of the audio will require full a decode/encode cycle.

[cedworld]

in fact it's a 1080p video so i really don't want to launch a full decode/encode cycle with it

i prefer the audio, and i tried Besweet but it doesn't work, the app does nothing exept corrupt my ac3 file...

[romi7519]

cant eac3to be used?

[AlanHK]

so i would like to know how convert the audio track (ac3 5.1) losslessly

Use this:
https://forum.videohelp.com/images/guides/p1938368/audioscale.rar
Just unrar to a folder, run "AudioscaleGUI". or make a shortcut to it.
Almost lossless, it stretches or compresses AC3 by duplicating or deleting frames, not reencoding.

(Got the GUI from http://forum.doom9.org/showthread.php?p=797909#post797909, but the actual executable web page is dead now.)

[cedworld]

yeah thanks i think it's exactly what i need !

i try

i have another question : where can i find azid.exe for besweet ?

[jagabo]

in fact it's a 1080p video so i really don't want to launch a full decode/encode cycle with it :D

In an AVI file the frame rate is just a pair of numbers in the header. Change the numbers and you change the frame rate. There is no decoding or encoding, no loss of quality. But a 1080p source probably isn't AVI.

[cedworld]

in fact it's a 1080p video so i really don't want to launch a full decode/encode cycle with it

In an AVI file the frame rate is just a pair of numbers in the header. Change the numbers and you change the frame rate. There is no decoding or encoding, no loss of quality. But a 1080p source probably isn't AVI.

no, it's a mkv avc

[cedworld]

finally, i give up the idea of audioscale, i get a "tic" too many times...

probably full reencoding is the best thing to do, so i need besweet and the azid.exe thing to work on ac3 stream with besweet, but i can't find it...


PS : DONE : eac3 do it weel

[jagabo]

I don't know for sure if it always works -- but MKV also has a frame rate setting you can change with AVC video. Using MKVMerge to merge a short elementary h.264 video stream with an audio stream I was able to set whatever frame rate I wanted. Playback with MPCHC was at the chosen frame rate.

It also has a "stretch" value for the audio. But when MPCHC played a file with streteched audio it seemed to modify the video frame rate, not the audio. This might not have been so bad but it did it by pausing the video once every second to make the video match the audio.

[BobSapp]

MKVMerge works. Just divide 25 by 23.976 and the result (1.0427093760) put in "Format specific options">"Stretch by": and Start muxing....

[wulf109]

TFM Audio Tool can change 25 to 23.96(Pal to NTSC) I've used many times without problems.

[FlankerB]

MKVMerge works. Just divide 25 by 23.976 and the result (1.0427093760) put in "Format specific options">"Stretch by": and Start muxing....

That is not a propper way to do this for all purposes. That doesn't change the audio stream, only the way it is reproduced and can introduce pitch change. Eac3to is the best way to do this (I believe it does pitch correction).