Audio Out Of Sync When Cutted

[pateras]

Hello to all.

I have a very strange problem to share with you and if anyone have an idea to help me it would be great.

So here it is:

I have bought and avermedia capture hd H727 device to use with my pc

When i capture via hdmi everything seems fine in all resolution and i have no problems playing the mpeg file after.

So i'm now using megui to convert with xvid the video.
Video converting just fine but audio is away out of sync but not always (not in all the captures)
Searching and reading i found that the problem appears when i want to cut of some parts with audio cutter.
If i encode the complete mpeg file without cutting everything seems fine.
But if i cut just a second from video and audio the out of sunc appears.

I've tried every possible adjustment and nothing happend.

The only solution i found so far is to use
1. mpeg header corrector to recreate the file
2. MPEG-VCR to demux mpeg
3. megui to encode video and audio after cut some parts.

with this steps final avi file works fine even audio is sync ok but it needs quite some time the whole process.

I'm running this with
Inter Dual core 2.2Ghz E4500
Ram 4GB
Vga Intel 82945G (On Board)
Windows Xp SP3

If anyone can help?

[DB83]

Have I understood you correctly ?

You capture as mpeg. Probably mpeg-2
Then you try to edit/cut that
Then you convert that to xvid

You are probably not cutting the video on an i-frame and that causes the mpeg to go out of sync

Try avidemux in copy mode to do the editing but make sure the bar indicates you are on an i-frame. There are other utilites also available that will cut on an i-frame.

[pateras]

Ok. Thanks for advise. I'll try and make post of results.

[hello_hello]

How are you cutting? I'm just wanting to confirm you're not doing anything "odd". I assume you're cutting as you encode, and not cutting the video before or after it's encoded? Is the audio out of sync by the same amount from start to finish or does it change as the video progresses?

Normal procedure would be to open the source video with MeGUI and index it (using the File/Open menu), and letting MeGUI extract the audio in the process.
You'd create an AVIsynth script for encoding the video and save it.
You'd then open the script with MeGUI's AVS Cutter and specify which bits you want to encode. When that's done you'd use the AVS cutter to save the cuts to the script and also save a "cuts file" to your hard drive.
The audio would then be opened with MeGUI's Audio Cutter along with the "cuts file" which it'd use to cut and rejoin the audio accordingly, or you'd load the cuts file into the audio encoding section and it'll be re-encoded using the same cuts as the video.
Finally the cut (or re-encoded) audio and the encoded video needs to be muxed into a new AVI/MP4/MKV (either manually or using AutoEncode or OneClick), and in theory the audio and video should be in sync.

Is the above process the one you're using? If so it shouldn't matter where you cut as you're not cutting the video as such, you're simply re-encoding just the bits you want and cutting/re-encoding the audio to match. I use the above method regularly without sync problems, but there's possibly a few issues which can cause it to go wrong on the odd occasion, however off the top of my head I can't think of any which would cause the audio to go out of sync if you're editing/cutting while encoding which wouldn't also apply when re-encoding the whole file.
If you're using the above process, can you capture/split/upload a small sample of video which can't be cut without giving you audio sync issues?

[hech54]

2. MPEG-VCR to demux mpeg

That's silly. Just CUT the mpeg file with MPEG-VCR since you have it already.
People's obsession with demuxing just boggles the mind.

[hello_hello]

What if MPEG-VCR can't cut exactly where you want it to without re-encoding the area around the cut point? Aren't you re-encoding a bit of the video in order to cut it before then re-encoding the whole lot?

And assuming you use MPEG-VCR to cut the file before re-encoding it, won't you have multiple sections which need to be joined back together after encoding? Isn't it impossible to add the audio from the original mpeg files to the output AVI without demuxing it?

[pateras]

How are you cutting? ....

I work exactly as you mentioned with megui and all the steps you said. Its not my first encode. I use this program for over 3 years now but i had another capture card installed.
The problem appeard since the new card installed (avermedia) and as i mention before not in all files (weird!!)

I tried avidemux as suugested by the friend above but no luck.

2. MPEG-VCR to demux mpeg

That's silly. Just CUT the mpeg file with MPEG-VCR since you have it already.
People's obsession with demuxing just boggles the mind.

If i cut with mpeg-vcr the result is same as megui. audio out of sync. So i demux the corrected mpeg and re-encode only audio to mach fixed mpeg.

Its really weird all this problem. Today i'm trying to do this with another pc just in case.
If that wont help i'll format and install win 7 and try again.
Thank you all for helping.

[hech54]

Check out the specs for this card:
http://www.amazon.co.uk/AVerTV-CaptureHD-Digital-Recorder-Support/dp/B002MRROO4

• System Requirements
• For TimeShift and Record in MPEG-2, Intel Pentium 3.0GHz with HT (Hyper-Threading) or equivalent
• For HDTV (H.264) Preview and HD/HDMI Capture: Intel Core2 Duo 2.4GHz or equivalent , 1G RAM or above, VGA card supports DirectX 9.0c or above, PCI-Express x1 Slot, Sound card, Windows XP/ Vista and Windows 7

[pateras]

Thanks heck54 I've already read that before buying this card. The weird problem is that the original captured file is synched without problems or frame losses. Also if i encode the complete mpg stream (without cutting) again it plays fine without sync problems.
So i figured out the problem is when i cut and not at minimum specs of my pc.
As i said i'll try change pc or even format the old one in order to test also the minimum specs mentioned.
I'll let you now the results.

[DB83]

Upload a sample capture - say one minute - with plenty of synced sound. Indicate what you want to cut out. You try it and then let us try the same.