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NeroVision "capture" of DV files corrupts aud... - 2/14/2005 2:31:52 AM   
waltersbg

 

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The only "capturing" I do of video is from my Sony TRV-330 Digital 8 Camera. I either capture digital video from the tape in the camera or I use the camera to convert analog video (from a VCR) into DV format. In both cases, the DV data is transferred to my computer via firewire.

I currently have 3 options for transferring the DV files. One is the capture option in Windows Movie Maker. I don't like this option because it seems to capture as DV-Type 1, which is not compatible with some other programs I use.

Another option is the simple little freeware program WinDV. It works fine but it doesn't have any control panel included, so I have to use the play, pause, rewind, etc... buttons on my camcorder and this is a pain.

My 3rd option is to use the "Capture Video to Hard Drive" in NeroVision Express (3.0.1.27). It seems to work fine. However, when I tried to use avisynth on the resulting .avi file (in order to apply filters and such before sending it off for encoding to mpeg2 with a dedicate encoder), avisynth complained of not being able to decode the audio. Initially, I just assumed that this was because of a missing codec or something on my system.

However, I noticed that DV captured with WinDV from the same camera and DV files that I had captured on another computer from the same camera using Pinnacle Studio both worked fine in avisynth. Hmmm...

So, I went and downloaded the Gspot codec info utility and used it to look at all my various DV-avi files. The DV-avi files which had been loaded by WinDV and Pinnacle all reported "PCM Audio" in the audio codec name field. However, the DV files read in using NeroVision Express say "0xfffe: <unknown>" in the codec name field and Gspot reports that it is "unable to find a codec which will decompress this format".

Windows programs are able to play the DV-avi files loaded by NeroVision Express OK, but anything that actually tries to use the codec information from the file gets confused. It appears to me that NVE is corrupting or altering some value in the DV-avi file. I thought that a DV transfer like this was just a transfer of data (as opposed to a video "capture") so I'm not sure why NVE would do anything to the data. Whatever the case, it leads to different results than the DV files that come from other programs.

I'd like to use NVE to capture my DV video, but I can't if it is going to result in a file that is not understood by avisynth and other programs. Am I the only one who has ever run into this? It wouldn't surprise me too much. I seem to have a knack for the obscure. Is there any chance that this is an NVE bug and will be fixed?

Thanks,
Mike


< Message edited by waltersbg -- 2/14/2005 2:37:21 AM >
Post #: 1
RE: NeroVision "capture" of DV files corrupts... - 3/3/2005 3:07:41 AM   
waltersbg

 

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Based on the lack of replies, I have a feeling that I am the only one who has run into this issue and/or cares about it. But, on the off chance that somebody who has run into this same problem searches the forum and comes across this post, here's what I've discovered:

The avi file contains a data structure (called WAVEFORMATEX) that describes the audio format of the audio portion of the avi file. In all my capture programs except for NeroVision Express, the value of the first field in this data structure, wFormatTag, is set to 0x0001. This equates to a format of WAVE_FORMAT_PCM.

For some reason, the DV captures done with NVE result in a wFormatTag of 0xFFFE, which equates to a format of WAVEFORMATEXTENSIBLE. This is a format that, according to microsoft, is supposed to be used for "waveform-audio data for formats having more than two channels or higher sample resolutions than allowed by WAVEFORMATEX". Since the DV audio is only 2 channels and uses a sample rate of 48Khz, there is no reason that I can see to use the WAVEFORMATEXTENSIBLE format.

Since the WAVEFORMATEXTENSIBLE is not a single, spec'd format but rather something that can be extended to add additional features, I don't expect to find a codec that claims to be able to decode it. I've considered just using a hex editor to modify the 0xFFFE to a 0x0001, but I don't think this will work because an additional data structure is added when using the 0xFFFE format so everthing will be out of whack if I just change this one value.

I guess, if I want to use the NVE-captured DV files with avisynth, I will load the files with the avisynth command "DirectShowSource" instead of "AVISource". By doing it this way, the NVE-captured DV files will use DirectShow to properly decode the video and audio. I wanted to stick with AVISource, since it feels like I have better control over which codecs are used, but it doesn't look like this will work with the "WAVEFORMATEXTENSIBLE" audio format that is part of the NVE DV avi files.

Just thought you'd like to know. LOL!

Later,
Mike


< Message edited by waltersbg -- 3/3/2005 3:09:43 AM >

(in reply to waltersbg)
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RE: NeroVision "capture" of DV files corrupts... - 3/6/2005 1:21:58 AM   
reboot


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Before you go running off complaining about NVE3, I did an experiment.
NVE3, by default, captures AC3 audio. YAY! Bonus! That's what we need for DVD, right?
Right...however...not one other program on your computer understands AC3 audio, so you can't edit, can't do much at all, without some sort of AC3 decoder.
Here's where it get's tricky. You can get a free AC3 decoder here: http://ac3filter.sourceforge.net/
Download and install it, and see if it fixes your NVE3 troubles.
If it doesn't, click on the configure button of the NVE capture window, and see if you can configure it to mp2. Even LPCM if necessary.
At least Avisynth won't choke on it :D

BTW, using NVE3, can you capture directly to mpeg-2 @ 720x480 with no dropped frames?
If so, just keep going through the program once the capture is finished, and it will output the finished DVD, all edited and ready.


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(in reply to waltersbg)
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RE: NeroVision "capture" of DV files corrupts... - 3/7/2005 3:14:02 AM   
waltersbg

 

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Joined: 2/8/2005
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reboot:

Thanks for your reply.

I don't mean to be complaining about NVE as much as I mean to be describing an issue with the DV-avi files that I "capture" with NVE. I'd love to use NVE for this part of the process, but the resulting avi file isn't working for some of the steps I'd like to take.

I'm curious to know more about the experiment you did. Did you capture Digital Video (DV) format directly from a camcorder (or other DV source) using NVE? That is the situation that I'm in here and I would be even more baffled if NVE was turning the audio into AC3 in this case.

NVE ENCODES to AC3 by default, but I'm not encoding here. I'm simply transferring the DV-avi data from my camcorder to my computer. The audio should be PCM, 2-channel, 48Khz, 16-bit. It does appear, in fact, that the audio in the NVE-captured file is this format but, for some reason, the audio format value is being set to 0xFFFE instead of 0x0001. If it was encoding the audio to AC3 format for some reason, the format value should be 0x2000, I think.

At any rate, I hadn't even realized that there were such things as .avi files with AC3 audio, so I decided to try your solution. I installed an AC3 decompressor on my system and tried loading the file into avisynth again. Same error as before.

The reason that I don't capture directly to mpeg-2 is that I'd like the freedom to run my encoding in 2-pass VBR mode (whether I use NVE to encode or Procoder or Quenc or whatever). I'd also like the freedom to run the avi through filters first. If I capture directly to mpeg-2, I give up those abilities.

In cases where my incoming video is very good and/or my desired output quality is not so high, I think that capturing directly to mpeg-2 and then taking it right through the process in NVE to produce the final DVD would be a great way to go. Unfortunately, my DVD player won't play along with that option, due to an issue described here:

http://www.cdrinfo.com/forum/tm.asp?m=100404&mpage=1&key=𘠴

Again, it may sound like I'm bashing NVE. Really, I'm not. I wouldn't spend so many hours trying to figure out how to make it work for me if I didn't want to ultimately make it my tool of choice. If I can just get around some of the issues described in this thread and in the one I linked above, I'd probably be using NVE for everything except maybe the most demanding captures that require extra filtering and long, slow, thorough encoding.

Thanks again,
Mike

(in reply to reboot)
Post #: 4
RE: NeroVision "capture" of DV files corrupts... - 3/7/2005 10:27:19 AM   
reboot


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Because it's Nero, I suppose anything is possible.
I did a direct capture from DV cam, via NVE3, then saved it to the hard drive.
Result, an avi in perfect condition, with AC3 audio!
Nero absolutely insists on transcoding it, and I see no other option except LPCM audio.
It won't simply "take" the file and save it, as is.
I seriously doubt that the Nero people ever considered that we (the general public) would attempt to use NVE for this purpose. I think they assumed we would be capturing TV or VHS, and use a different app for our DV sources.
Anyhow, having it saved with AC3 is sort of a blessing in disguise, as there are not many apps that can take ac3, in a program stream (or elementary streams for that matter) and edit them successfully.
Just another reason to not use NVE I suppose.
You've done a lot more experimentation with it than I, and I would have given up long ago, in favour of something like Vegas, Pinnacle, or Premiere.
Even those can complain about AC3 (or simply not "see" it), without some sort of plugin (usually costing more $$$).
I even purchased the tmpgenc AC3 plugin for DVD Author, and Mpeg editor, and it never did work. I'm in the process of returning all my tmpgenc software, in favour of something that does work! In this case, I'm leaning towards Mainconcept EVE. Integrated with their superb encoder, you can't go wrong.
I know this isn't what you wanted to hear, but it's all I can come up with for now. Hopefully others will have suggestions/solutions for NVE.


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Who needs a life, I have internet! :D

(in reply to waltersbg)
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RE: NeroVision "capture" of DV files corrupts... - 3/7/2005 1:11:26 PM   
waltersbg

 

Posts: 13
Joined: 2/8/2005
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reboot:

Thanks again for your reply.

How did you determine that the audio of the captured AVI was AC3? My captured avi file can be played fine in all the player aps (using DirectShow, I assume), so I wouldn't even be worrying about the audio format if it weren't for the fact that I tried to open it in avisynth. Every codec identification tool that I can find, indicates that the audio format is "extensible" or "ogg". I haven't found anything to indicate that it is AC3. How did you figure this out?

I wonder what would happen if I set NVE to encode in LPCM format? If I set that as the default and then went back into NVE and captured DV from my camcorder, I wonder if the audio format would change to PCM and then I could successfully load it into avisynth without using DirectShow? I'll have to try that.

I take it as a personal challenge to figure out how to work with what I've got. I hate spending money on new programs if I can make what I've already got work. Since Nero came with my DVD writer, I'd like to make it work. I'm also trying many freeware programs. The last thing I want to do is to purchase another $60-$100+ program to do what I should be able to do with what I've got. Then again, if my time is worth anything I've already spent a lot on this!

Thanks,
Mike

(in reply to reboot)
Post #: 6
RE: NeroVision "capture" of DV files corrupts... - 3/7/2005 5:12:32 PM   
reboot


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Joined: 3/6/2005
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Gspot reports that it's AC3.

Try recording LPCM audio, you've got nothing to lose but a little time, and at least it will be editable in just about any program you want (if NVE is doing what I think it's doing).

The reason behind my thinking, is this: Nero must interface with the cam and the hard drive. In order to do that, it must recognize the input, and then determine an output. The cam cannot write to the hard drive, thus Nero must be doing it. If Nero is doing it, it follows that whatever options you set in NVE are determining the output from NVE to the hard drive.


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Who needs a life, I have internet! :D

(in reply to waltersbg)
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RE: NeroVision "capture" of DV files corrupts... - 3/8/2005 5:03:02 PM   
waltersbg

 

Posts: 13
Joined: 2/8/2005
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reboot:

When I run Gspot on my DV-avi's that I capture with NVE, the audio codec is unknown (format 0xFFFE, like I said in my original post). I wonder why yours is showing up as AC3. Is it possible that your camcorder is encoding it as AC3 and Nero is just passing it along?

At any rate, I will try setting the NVE default to LPCM and see what happens.

Thanks for your input,
Mike

(in reply to reboot)
Post #: 8
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