Quality problems after merging two .avi files

[Metallo]

Hi,

I have transferred two DV cassettes from my digital camcorder to my PC in order to compress the files in DVD format.
Sometimes, my camcorder has problems with mosaic effect, especially when it is too warm, therefore the effect appears in the DV files I have transferred, but I can live with it.
If I watch the files on my PC using either WMP11 or VLC, you just see the little squares appearing and that's it.
I decided then two join the two files (13 GB every file) and used the latest version of VirtualDub to open and append them.
Once the merge was completed, it looked perfect but...when the mosaic comes in it becomes no longer a visual effect but and audio effect too.
Every small variation sounds as pops and crackles in a vinyl lp.

No idea why this happens, hope somebody can clear up my mind.

Thank you folks.

Alex

[Baldrick]

Are you using video->direct stream copy and audio->direct stream copy settings in virtualdub?

[redwudz]

If you are using Direct stream, then maybe the tape itself has damage. That could explain why it also affects the audio. And could you describe more fully what you mean by 'mosaic'? It has a lot of interpretations. A screen shot would be helpful.

If it's 'macroblocking', VD has some deblocking filters available that may help. http://compression.ru/video/deblocking/index_en.html But you would have to re-encode, at least that portion of the video. I use the Cedocida DV Codec for that.

And it likely makes no difference, but what program did you use for transfer? I use WinDV most times. You could also try a different DV type, DV-1 or DV-2, though I doubt that will help. But they do use different audio handling methods. The newest VDs can handle either format.

[poisondeathray]

If the separate files already have the mozaic artifacts, joining them won't "fix" it.

I find avidemux handles appending files better than vdub, especially for audio sync issues - worth giving it a try imo

[filmboss80]

Are you seeing the macroblocks in the camcorder image BEFORE encoding to the computer? If so, it is either dirty camcorder tape heads or (like redwudz said) damaged tape. Get a minidv head cleaning tape and run it very briefly in the camcorder, then play the tape in question again.

[Metallo]

Hi,

I read all your comments and here my questions/statements:

Yes, by mosaic effect I mean macroblocks.
My camcorder has this problem since two/three years after I bought it (Panasonic NVDS33EG), it is not depending on the cassette brands, 'cause I tried different ones with same result, it is not depending on dirty heads either, 'cause they are clean, I noticed it does it after one hour of use in playback, it is not much and it occurs mostly were zooming is involved in the recording.

Now, the DV files are transferred using WMM 2.1 and are definitely DV-Type 1.
The .avi files I get play fine, exactly the same as the tapes (with the same small areas of macroblocks).
I don't want to re-encode them, no way.

Obviously, I use video->direct stream copy and audio->direct stream copy settings.

What I did, I have encoded them to .m2v/m2a for DVD and now I will have to find a way to join the two files together, that should give me the expected result.

I will also try avidemux though, I am convinced the issue is in VirtualDub, the compressed m2v/m2a are perfect without any crackles in correspondence with the macroblocks.

Cheers
Alex

[Metallo]

Well, I have installed Avidemux 2.4.3 and tried to open the two dv files, it simply fails to do so, message is:

Attempt to open M:2008_07_Canada. avi failed!
Could not open the file

I tried the two m2v files I got from the master DV files and it fails to open them too.

It's not a good start with a new application

Alex

[Metallo]

If the separate files already have the mozaic artifacts, joining them won't "fix" it. I find avidemux handles appending files better than vdub, especially for audio sync issues - worth giving it a try imo.

Well, I have installed Avidemux 2.4.3 and tried to open the two dv files, it simply fails to do so, message is:

Attempt to open M:2008_07_Canada. avi failed!
Could not open the file

I tried the two m2v files I got from the master DV files and it fails to open them too.

It's not a good start with a new application

Alex

[poisondeathray]

Now, the DV files are transferred using WMM 2.1 and are definitely DV-Type 1.
The .avi files I get play fine, exactly the same as the tapes (with the same small areas of macroblocks).
I don't want to re-encode them, no way.

Cheers
Alex

DV Type 1 cannot be handled by VFW (video for windows), which vdub uses.

Here is a free converter
http://www.ulead.com/download/dvconverter/download.htm

[Metallo]

Now, the DV files are transferred using WMM 2.1 and are definitely DV-Type 1.
The .avi files I get play fine, exactly the same as the tapes (with the same small areas of macroblocks).
I don't want to re-encode them, no way.

Cheers
Alex

DV Type 1 cannot be handled by VFW (video for windows), which vdub uses.

Here is a free converter
http://www.ulead.com/download/dvconverter/download.htm

Are you suggesting to convert my master file from type 1 to type 2 so that VDub can possibly do a better job?
Why then VDub does not prevent me doing the merging by saying it cannot handle type 1?

Thank you for your help
Alex

[poisondeathray]

I rarely deal with DV these days, so maybe some other people can chime in here if there are faster/better methods. This is how I remember doing it a long time ago so maybe things have changed?

https://www.videohelp.com/glossary?D#DV

[redwudz]

The newest versions of VD can handle Type 1 or Type 2 DV-AVI. The audio handling is different with each type. You should be able to convert them back and forth to either format with no quality loss.

I'm was thinking converting to Type 2 'may' solve the audio problem. But I would try it with a short clip or a copy of the original so you don't damage it. The macroblocking filter is probably still worth a try, though I don't know how well it will work when the problem seems to be with the camera. You are probably correct that it is heat caused. Using zoom would likely make it more obvious.

With VD you can also use 'conditional filtering', if I have the correct term. That's where only a part of the file is filtered, not all. Or use the 'old fashioned' way and cut out the problem part, filter it and add it back in.

[Metallo]

Hi,

I changed everything to type-2 using the ulead freeware converter but, believe it or not, it messed up the audio making larger part of the files without any audio and just background noise , I don't know the exact term in English, but to describe it, when you get a TV channel and no broadcasting station is received, you just see and hear ground noise, is this the right term??
The video is there but the audio is mostly ground noise.

So, in order to solve definitely the issue, I will use WinDV to rip from the master cassette in type-2.
I will also try to do the ripping in one go, so it won't be needed to join the two files later. I hope WinDV gives me this possibility.

I did not expect to have so many problems to join two avi files, unbelievable.

I tried Avidemux to join the two type-2 files, but have realized that it encodes everything from the beginning, therefore VDub remains my first choice.

Cheers
Alex

[redwudz]

The background noise is probably what we call 'static' or more properly 'white noise', consisting of most all audio frequencies or random noise.

WinDV is a simple program that just does one thing and does it well, transfer DV. You can adjust it to transfer as one large file or by pieces. If you go to the authors site, http://windv.mourek.cz/ , there's a screen shot at about the middle of the page. Run your mouse over it and it explains the functions available.

[Metallo]

The background noise is probably what we call 'static' or more properly 'white noise', consisting of most all audio frequencies or random noise.

WinDV is a simple program that just does one thing and does it well, transfer DV. You can adjust it to transfer as one large file or by pieces. If you go to the authors site, http://windv.mourek.cz/ , there's a screen shot at about the middle of the page. Run your mouse over it and it explains the functions available.

Hi,

I ripped the two DV files again from the master cassette using WinDV.
It worked perfectly, ripped as type-2 this time, but I have not understood how I could possibly rip two cassettes in one single file. In fact, once the first tape was at the end, I clicked the "Capture" button to pause everything, inserted the second tape and clicked again the "Capture" button. The second tape was ripped as a file on its own.
However, I used VDub to join them and this time, probably because the file was type-2, the merge was perfect under any aspect.

Oh, I forgot to tell you that I fully succeeded to eliminate the macrobloking problem, you know how?
Well, it's really hot these days in Italy, I have a fan close to me and decided to divert its flow towards my camera in order to prevent over heating. It worked ! Not a single macroblok in 2h and the whole device was really "cool".
So, I am now sure that the problem is due to the heat of the camera after, say, 1h playback.

That's all for now.

Cheers
Alex