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Old Feb 4, 2006, 9:30 PM   #1
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I downloaded the Gardian Knot Codec 1.9 and then used Mp4Cam2AVI to convert some of my very first videos froma VPC-C6 to avi. I then used ShowBiz DVD2 to create a DVD.

It seems to me that the video is a little out-of-sync with the sound. My husband doesn't see it but I'm convinced that there is a mismatch - a short delay in mouth movement compared to sound in playback.

Has anyone else experienced this? I'm not really into doing much more for post editing but if there are particular settings I should be using in Mp4Cam2AVI that would improve this or perhaps other quick steps I'd love to know - otherwise the camera may be going back.

Thanks
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Old Feb 5, 2006, 12:31 PM   #2
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The first thing to do would be to shoot a test video with precise sound, and play it back on your TV directly from the C6. If the sound is OK there, then your problem lies in the software you use to create the DVD. If the sound is out of synch when you playback directly, then there is something wrong with your C6.
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Old Feb 5, 2006, 8:22 PM   #3
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Thanks for the help scrambler. It's the software. Playback was fine on the tv.

What kind of editing software is capable of letting the user add images, sounds, transitions, etc for these mpg4 files?
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Old Feb 5, 2006, 9:03 PM   #4
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If you have an mpeg4 codec installed (which you do as you can play the files on your computer), then most editing software will be able to open the file and let you edit it. what happens is that when it loads your file, it uses the codec to decode it , then it performs the edits and add on on the decoded file, then when you want to save your modified file, you will need to re encode it. At this time you can re encode in an mpeg4 or any other format for which you have codecs for.

There are various editing software with more or less capacity depending on cost. The Free (with XP) windows moviemaker will let you edit, add transition, title and some effetcs as well as sound, but only re encodes in Wmv Format (at various compression rate)or DV.

There is a free SW called VirtualDub which can do quite a bit of treatment on the video, and can re encode with the codecs available on your machine. User interface is not very ellaborate, but it is efficient.

Then for a moderate cost you can get SW like Ulead Pinnacle Studio or Adobe premiere.

Then you can move onto more professional SW such as Combustion from Discreet (now Autodesk)

Re encoding potentially means some loss of quality especially if you re encode in a radically different format, but not necessarily. Ideally you would want to be able to perform edits and add on in the original format, but I do not know what software (if any)can edit and modify video in the mpeg4 format.


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Old Feb 5, 2006, 11:15 PM   #5
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Collinsk:

According to MP4CAM2AVI website, this program is supposed to repair the AV desynchronization:

http://mp4cam2avi.sourceforge.net/index.htm#faq

"There are many video converting apps. Why should I use MP4Cam2AVI?

........

3. It fixes audio/video sync issue. Audio and video lengths in MP4 video fragments are not exactly the same (i.e. for Sanyo/Fisher C1, audio is ~50ms shorter). When you join many video fragments, you will have audio/video desync increasing to the end of the target file. MP4Cam2AVI solves this problem - it inserts silence when audio stream ends or crops 'silent' frames at the end of each fragment."

Maybe you are hearing a brief period of silence produced by the MP4CAM2AVI so that the A & V streams are now matched up. Or maybe this repair process is not absolutely perfect.

If you are meticulous about getting the audio and video absolutely right, and you are computer savvy:

a) You should first play the video to see whether the audio or video lags behind. If you are telling me there is a slight lag of the lips movement after the speech, the video lags slightly behind the audio.

b) "Demux" (separate) the audio stream from the video: eg. AVIMux (freeware)

http://www-user.tu-chemnitz.de/~noe/Video-Zeug/AVIMux%20GUI/

c) If your video editor does not support AAC audio used by the Sanyo, use an independent audio editing program to re-encode the audio to WAV. You should note the original sound quality (frequency, bitrate) if you want to match it in the new WAV file:

freeware audio editor #1 - DBpowerAMP (v.10 is the last freeware version) - simple user interface, only for conversion:

http://soft.li.ru/dbpoweramp_music_c...e_v10_1-752-2/

freeware audio editor #2 - audacity - complete tweak of audio file:

http://audacity.sourceforge.net/

d) Re-constitute the audio and video streams in your video editing program - this depends on which program you use but I am sure VirtualDub can do this (audio must be in WAV format).

freeware video editor VirtualDub:

http://virtualdub.sourceforge.net/

Using VirtualDub (VD): I won't go into the exact keystrokes unless you are really pursuing this!

You should open the (original) video in the prgram first, and chop off some frames from the very beginning or very end of the video, depending on whether the audio or video lags behind.

** From what you said about the lips lagging behind the speech, you should try chopping a few tens of miliseconds of frames off the very beginning of the video. **

Then you can insert the WAV file to replace the original soundtrack of the video, and see if it matches up; in VD you must re-encode the video in order to see the result - but you can interrupt the encoding after a few seconds to see a sample of a few seconds of the converted video.

It may take several attempts because there is a lot of trial-&-error involved.

(I suggest clipping the video to match the audio, presuming from the description by MP4CAM2AVI that the Sanyo Xacti always produces a shorter audio file about 50 ms shorter than the video)

RE: scrambler's concern about quality loss from re-encoding:

Note that MP4CAM2AVI does NOT re-encode or modify the original MP4 data in any way: it merely changes the "container" ("MP4" versus "AVI") information of the file, so that the computer can recognize which video codec to use to play the video. The actual video data is not altered in any way, because it relies on the similarities between many MPEG-4 codecs, such as MP4 (from Apple) and DIVX/ XVID, that they can be played by each other's codecs.

At least in VD, there is an option (in both "video" and "audio") for "direct stream copy" - this ensures NO re-encoding and no loss of the original quality of data. If you are still in doubt, there is another option to make "uncompressed" file (original Windows AVI), so that you can assured that there is absolutely no video compression.

Audio compression and re-encoding is not as traumatic to our ears as video compression to our eyes (unless you really lower the re-encoding audio file quality significantly!!). In any case, I suggest converting the original AAC codec to WAV - WAV is the "uncompressed" audio format: this produces a HUGE audio file but ensures there is no loss of the original audio quality.

Therefore, if you are really meticulous, it is possible to do all the above tweaking without any loss of the original video and audio quality, until the step you use a DVD converting/ burning software, when the video and audio streams are now actually being re-encoded/ compressed to DVD format.

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Old Feb 6, 2006, 2:54 PM   #6
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I think the real problem comes from the fact that if you glue together many small fragments the offset will slowly increase and you can't fix it uniformly through all the movie. It will be very annoing to fix each fragment separately. I don't know the solution for you in that case.

My solution (when I finally get the camera) will be to just keep the video in the format the camera made it. Why should I re-code it at all? :-)
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Old Feb 7, 2006, 1:11 AM   #7
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Androxylo:

"Why re-code it at all?"

This goes all the way back to collinsk's original description:

Because most people want to burn the video onto VCD or DVD to play it on the TV by their DVD player. Although MPEG-4 DVD players (which plays DIVX/ XVID, many acutally requiring "DIVX certified" formats) are getting popular, none will play "unmodified" MP4 video files.
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Old Feb 7, 2006, 12:52 PM   #8
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blindsight wrote:
Quote:
Because most people want to burn the video onto VCD or DVD to play it on the TV by their DVD player. Although MPEG-4 DVD players (which plays DIVX/ XVID, many acutally requiring "DIVX certified" formats) are getting popular, none will play "unmodified" MP4 video files.
Maybe it's worth to re-check awailable mpg4 players that are popping up every day and have a range $40-$60. Maybe some of them already play the vc6 format as is.

If not, the solution is either have your PC connected to your multimedia output system, whatever it is (as I do with my projector) or to buy a new multimedia computer.

The Microsoft-based media center PC will cost you $300-$400, but if you want something smaller and cheaper, there are some new Linux-based devices coming out, like:

http://www.onlybestrated.com/mvix-mv...iter-p-65.html

They are usually pretty small and you don't pay the heavy Microsoft tax. Another one:

http://www.shop4tech.com/?go=view_it...4760&r=183
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Old Feb 7, 2006, 1:00 PM   #9
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You can turn any PC into a sort of a Media center, all you need is to have a Video card with Video output. I have an old PIII, I put an ATI all in Wonder in it (it is even only a PCI card), I got it for cheap on Ebay, and I use my PC as a TIVO, a VCR, and I can view all the Videos on the Web on my TV.

Of course it is not powerfull enough to play the C6 Mp4 smoothly, so I am going to have to upgrade sooner or later anyway.:roll:
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Old Feb 7, 2006, 1:07 PM   #10
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Thank you all for your help. The issue for me however is to create movies out of the video I take and put them on dvd for easy playback for myself as well as family members with various types of dvd players, computers, etc. I often add menus, other pictures and images, funny sounds, etc. I really am looking for a product that will permit me to do this as I can now with my minidv tape footage.
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