Sound Out of sync in encoding Divx Movies

hamster

I recently got a hold of FlaskMpeg (.594 Intel Version) and Divx 5.02 and the Radium codec for sound. I tested it out on a movie to see what kind of quality was achievable and must say I was impressed. The only snag I have is that the sound gets out of sync after 30 mins into the movie (or just move the movie forward a few minutes and back again). Now I read about encoding the sound sampling rate at 48KHz rather than 44.1KHz. The encoding in FlaskMpeg was done with sound and video combined (ie I didn't separate the sound and fix it in VirtuaDub). Just curious, did anyone find this a problem or has used VirtuaDub or something similar?

lynchie

I use the Gordian Knot Rip Pack for doing all ripping/encoding and I havent had one file out of sync yet. They all work perfect. Check out doom9.org for more info.

elmer

the sound sampling rates are changable in flask mpeg - well for the next time . like lynchie i'd recommend taking a look at gordian knot - great package with excellent quality

as for fixing the existing movie take a look at

http://nickyguides.digital-digest.com/audio-synch.htm

you should be able to ignore most of the article and jump straight in to the virtua dub bit . check towards the end of the movie as the sync will probably be out most at that stage

hamster

Hmm.. the Gordian Knot Rip Pack looks interesting alright. Thanks I'll give it a whirl and see how it goes!

CivilServant

So if you have something that's out of sync how do you repair it?
The film plays grand from the start but if I fast forward it goes totally out of sync which sort of suggests that the movie length and sound length are different lengths. I think?

The original copy was fine but was burned on a bad disc, (vivastar:mad: ) and ripped with isobuster, but the last few sectors contracted lepersy and are unrecoverable.

hamster

CivilServant,

Try what Elmer suggests: http://nickyguides.digital-digest.com/audio-synch.htm I hope to try this later. I have a movie that starts out fine and gradually gets out of sync. I'm going to play around with the gordian knot package first.

elmer

I've found the vivastar disks to be very good - yeah virtuadub will do the trick for all your resyncing needs

hamster

I read in the documentation that encoding with LAME at 96Kbit at 48Khz still gives syncing problems (and actually is downsampled) so I'm going to try 128Kbit rate instead.

Stark

you can extract the sound from a divx film using virtualdub (open the divx in virtualdub and use Save Wav... on the left). From there you can use lame to re-encode the wav, using lame -b 128 --resample 48
You can then re-mux the audio using virtualdub. Under the audio menu, instead of AVI audio choose Wav...
Be aware though that re-encoding mp3 is like taping a cassette from a cassette, you lose quality each time.

The points to watch out for are don't re-sample the original audio and don't use variable bit rate or average bit rate mp3 because AVI is poorly equipped at handling them.

(If you want a proper solution try using OGM instead of AVI and vorbis instead of mp3 - you can encode the audio at 56kbps). You can actually use the OggMux/graphedit to directly convert your AVI to an OGM file which might fix the sync problems without the need to re-encode.

sceptre

^ er, what he said

(nice technical bit put simply)


I dunno about this encoding audio at the same time - it doesn't help if your machine isn't pretty damn fast. WIth my aging p-500 I still like to do audio and video on their own and combine at the end. I've only had synchronisation problems once (with Abre los ojos - first time using a R1 disc). Gordian Knot gets good reviews from everywhere though - if your machine is good enough to do it all in one sweep, good for you.

You might run into a minor annoyance when resyncronising the audio using the steps outlined on digital-digest (or using any other method). If you resynchronise so it's perfect on your machine you may notice problems playing the file on other machines. It's caused by the same problems that occur when you fix bad frames on an encoded file. Might not bother you at all (or affect you) but just something to be aware of in advance.

elmer

gordian knot does it all seperately too sceptre - it just batches it up so you can leave it and let it get on with it

maxheadroom

The best site I ever found with step by step instructions for ripping using gordion knot is http://www.everwicked.com


I've never had synch problems in AVIs using MP3 or the original AC3 track, but ogg and the ogg container seems like a much much better solution.


Now, if only I could find a proper subrip file for amèlie I'd be sorted...

elmer

I have amelie at home - you want the vobsub or just a text version?

maxheadroom

a text version - I've got all the files from the DVD on my HDD (taking up about 9GB including the various versions of the audio and DIVX files I've made), but I can't get the subtitles to rip to text properly, and I can't use vobsub files in an OGG container.

pickarooney

Here's a text version of Amelie subtitles in English, if that's any use to you. It's based on time rather than frame numbers, so it should be easy enough to match to the video.

pickarooney

Ack, didn't attach it. Here:

hamster

"Ogg Vorbis is a new audio compression format" and is supposed to better at lower bitrates? Is this true? I heard of ogg back in September. I think I'll try it out... I tried out mp3pro there and an example of it was that a 96kbit bitrate sample was as good as a 128kbit sample and even runs on non-aware mp3 players as mp3.

But Ogg sounds interesting?

sceptre

Ogg is open source so no-one need feel guilty about encoding using the hacked external Fraunhofer mp3 codec that they may have downloaded from the web if they use Ogg instead.

That's one advantage for starters. Quality is quite good too.

hamster

Yes, it looks good too at lower bitrates... looking for a good ogg encoder at the moment.

Just came across "speex". It's pretty good at encoding speech between 8kbs and 32kbs. I have a lot of audiobooks and seems like a good idea. Although converting the lot back to wav and into the desired format is destructive but maybe for future endevours...