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processing of audio in AV capture

Started by cyber, 2009.05.05, 10:04:22

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cyber

Hi all, I have problems with video I capture using OS/2; audio isn't synchronized with video, it late for several seconds (this way TV show was emited, recording is OK.). Now I want to synchronise audio and video and do not know how to do this. I was try even on friends Win machine with Virtual Dub and some video editing studio I found, but there is no option at all for such thing ?  Any experience wich program can do this moving audio in to stream ?

Saijin_Naib

I'd just use Premiere to clip the audio and sync manually. I think some programs can also sync automagically (Any Video Converter).

cyber

While waiting ot access Win machine I've found a solution:
1. edit audio by cut part of selected seconds in wav file from begining and paste to end of file (not delete!) with SS!
2. join audio and video with mencoder, test - there is no need to wait to process whole file, after start join-in it is posible to watch video file with WV or mplayer while is still converting.
3. then deleting parts of unwanted video also with mencoder.

Using complicated and long comands and paramethars lead to mistakes, so i write some scripts to do parts of this procesess and now is OK. :)

And all this using OS/2 or eCS. Anyway, thanks Saijin

The Blue Warper

Hi, cyber,

I never used it, but ProjectX seems the right match for your needs.  Jürgen Ulbts made a version that runs on OS/2:
http://www.rbri.org/projectx/projectx.html

Regards

cyber

I was tried it some years ago and mainly ProjectX has no usable codec output support for me. And on my machine (PIII 550MHz 256Mb) using Java program to edit larger video files is pretty slow, while ffmpeg and Mencoder work surpriseosly fast.
But isn't bad idea to use MPEG2 while editing and then convert to any other format. Thanks, I've check current version.

warpcafe

Hi,

I can only speak for Windows, where I use ProjectX and that runs perfectly for re-synching the audio.
I basically do the demux with ProjectX (corrects the wrong offsets) and then cut this (commercials, lead-in/lead-out) by using Mpeg2Schnitt. Afterwards, the stuff is muxed back into the output (mux is done from Mpeg2Schnitt automatically by calling external batch).

The truth however is that while ProjectX works also fine on OS/2, I can't tell what one can do with its outputs  later, since there might be an issue with codecs and/or software to get a muxed, usable output from this.
OTOH, I don't think it is impossible, perhaps someone here can tell what is available...?

What is the file format of your "raw" recordings? MP(e)G, PVA, ...?

HTH
Thomas
"It is not worth an intelligent man's time to be in the majority.
By definition, there are already enough people to do that"
- G.H. Hardy

cyber

#6
Quote from: warpcafe on 2009.05.08, 15:29:43
I can only speak for Windows, where I use ProjectX and that runs perfectly for re-synching the audio.
I basically do the demux with ProjectX (corrects the wrong offsets) and then cut this (commercials, lead-in/lead-out) by using Mpeg2Schnitt. Afterwards, the stuff is muxed back into the output (mux is done from Mpeg2Schnitt automatically by calling external batch).

The truth however is that while ProjectX works also fine on OS/2, I can't tell what one can do with its outputs  later, since there might be an issue with codecs and/or software to get a muxed, usable output from this.
OTOH, I don't think it is impossible, perhaps someone here can tell what is available...?

Output is not problem, with Mencoder and FFMPEG You can convert in whatever You want. I've tried and understand how to cut chunks with ProjectX, but no idea how to sychronise audio ???  What demux is for ?

Quote from: warpcafe on 2009.05.08, 15:29:43
What is the file format of your "raw" recordings? MP(e)G, PVA, ...?

Ive use just native OS/2-eCS codec: I think it is Ultimotion, it have good quality but it has way larger files than DivX or similar.

warpcafe

Hi,

demux = de-multiplex.
In the program stream you'll get audio and video data in the same "file" (or signal).
De-muxing will split the file into 2 files. 1 with the audio, 1 with video.
During that process, projectx is able to re-synch the data by correcting the contained timecodes which are most often not correct (is that by intention? ;) ).

In order to burn this on a DVD or to simply feed it to a playback device, again 1 file only is expected to contain both types of data (audio, video), so this is when you "mux" the stuff again.

Hope this explains.
And yeah, I know... cutting isn't really ProjectX's sweet spot. However, the way is quite similar to how other programs do it: cut-in point, cut-out point, etc... but other programs are more comfortable. However, it also depends only on what "view" you have selected in ProjectX... I'll try if I can find the one-page tutorial again, it explains quite good... (it's somewhere on the internet, I have to scan my bookmarks)

Cheers,
Thomas
"It is not worth an intelligent man's time to be in the majority.
By definition, there are already enough people to do that"
- G.H. Hardy

The Blue Warper

Quote from: warpcafe on 2009.05.09, 22:22:44
I'll try if I can find the one-page tutorial again, it explains quite good... (it's somewhere on the internet, I have to scan my bookmarks)

Hi all.

Well, I don't know if this is what Thomas was referring to, but here's a ProjectX tutorial with some screenshots:
http://www.doom9.org/DigiTV/projectx-fullguide.htm

cyber

Yeah, this is gonna be over-muxing; I've got recordings in Ultimotion video and wav audio, then I should pack 'em together in to MPEG2 for ProjX, then demux 'em using ProjX to sync and mux again to cut unwanted scenes and then I could use FFMPEG to pack em' in to final target format (This is not should be MPEG2 for DVD)?
Using command line with lot of paramethars and file names doesn't look such complicated when compared to this process. ;) For sure is faster.
There is one more question from me, related to precise determine cut-in and cut-out points; is any of our native players can play slow and frame by frame like ProjecX?

warpcafe

Hi!

Quote from: The Blue Warper on 2009.05.10, 01:12:35
Well, I don't know if this is what Thomas was referring to, but here's a ProjectX tutorial with some screenshots:
http://www.doom9.org/DigiTV/projectx-fullguide.htm

Yeah, "doom9"! That is exactly the one I was referring to. :)
Thanks for chipping in!

Regards,
Thomas
"It is not worth an intelligent man's time to be in the majority.
By definition, there are already enough people to do that"
- G.H. Hardy

warpcafe

Hi cyber,

Ah, OK - your streams are already separated... OK. I didn't exactly understand the implication when you said "Ultimotion". Got it now.
Well, since I have to deal with MPEG2-streams, for me it is very convenient to have ProjectX doing the offset correction since I need to de-mux the stream anyways. In your case I think you can either check whether a program like PVAStrumento exists for OS/2 (not sure if it is Java) or perhaps use ProjectX too - I don't know. But basically it should support input with separated audio and video (?). Not sure however if timecode correction (re-synch) will then work the same way (if works at all).

For the players, I can't tell. Sorry.

Cheers,
Thomas
"It is not worth an intelligent man's time to be in the majority.
By definition, there are already enough people to do that"
- G.H. Hardy

cyber

Quote from: warpcafe on 2009.05.11, 11:56:10
Ah, OK - your streams are already separated... OK. I didn't exactly understand the implication when you said "Ultimotion". Got it now.

   Ahem... I think that Ultimotion can carry audio too but mine recordings are separated, because some old OS/2 recording exe limitations.  I wasn't think earlier this may be important.

Quote from: warpcafe on 2009.05.11, 11:56:10
PVAStrumento exists for OS/2 (not sure if it is Java) or perhaps use ProjectX too - I don't know. But basically it should support input with separated audio and video (?). Not sure however if timecode correction (re-synch) will then work the same way (if works at all).

   Nope... PVAStrumento is dark side only... If video editing does matter, eCS is 10 years behind. Or more. :( 
But You give me some idea I need to check.

cyber

>But You give me some idea I need to check.

Dead end.  I've assume that something is possible using Mencoder, but no way.  :(

Making it manual using comand line kick ass.  8)  Fortunatly, I do not need to do this often.

sebi1234

I was tried it some years ago and mainly ProjectX has no usable codec output support for me. And on my machine (PIII 550MHz 256Mb) using Java program to edit larger video files is pretty slow, while ffmpeg and Mencoder work surpriseosly fast.
But isn't bad idea to use MPEG2 while editing and then convert to any other format. Thanks, I've check current version.




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