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话题: 48khz to 44khz conversion without re-encoding video?

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Is there a way to convert existing ripped MPG files that have 48khz to to 44khz without re-encoding the whole file again? I have tried many methods with no luck...

for those who don't know why this is important...
You have just ripped your promo only DVD and all the videos look great coming straight from the disc.
But when the audio plays is sounds like ... well it just sounds bad.. .. after some research here on this forum I have found it was the sampling rate. 48khz is the problem. It sounds soooo much better at 44khz from some reason using VDJ. I would love to keep the video at its orginal ripped state with only re-sampling the audio... without too many steps.. there is alot of videos to go through... or is this a topic that should be put on hold due to an update to software that will fix this audio problem?

anyone.. anyone?
 

发表时间 Sat 31 Dec 05 @ 10:11 am
TMPGenc will de-multiplex the mpeg file into audoi and video streams, you can then convert the audio stream and (re)multiplex into mpg2..
 

发表时间 Sat 31 Dec 05 @ 3:58 pm
I tried that.. but the thing is when you demultiplex it is a 48khz 16 bit wav file. After resampling and normalizing if needed in Sound Forge I saved it as a 44khz 16 bit wav file. I then tried to multiplex them back with no luck. It will only accept AC3 (dolby digital) or MP2 (layer 2) audio streams. I then started saving them as MP2... what a pain.
 

发表时间 Sat 31 Dec 05 @ 7:34 pm
That is because you are trying to create a SVCD compatibel mpeg2 file. you can create a 'normal' mpg2 stream with a 44KHz wav file. Or at least afaik..

but you should really check doom9.org for more info..
 

发表时间 Sun 01 Jan 06 @ 1:13 am
I am not trying to create a svcd compatible mpeg2 file....

I am simply demultiplexing and attempting to multiplex it back using the the PCM Wav audio and M2V file. Believe me I know the drill. I have been doing video stuff for some time now. I was just curious why can't I multiplex it back using a wav..

you try the experiment...
grab any MPG2 or VOB file ripped from a PCM audio DVD disc. Demultiplex it using TMPGEnc Plus and try to even multiplex what you just ripped apart... won't work. it has to be a MP2 audio or AC3 for it to work.
 

发表时间 Sun 01 Jan 06 @ 1:19 am
A couple of things:

First, I found that by improving my sound card, I could use VOBs without any lag. I went from a Sound Blaster Audigy 2 zs to an X-Fi card. This jump imporoved my ability to play VOB files with no noticable lag.

Next, If you can play your VOBs (or MPEGs for that matter) using your external decoder (in your extensions set up), you won't have to worry at all about making any conversions.

Finally, IF YOU MUST CONVERT, I recommend a program called MPEG-VCR and others recommend ImToo MPEG Encoder. The latter program (although I haven't tried it in a full version) is supposed to allow you the ability to do batch conversion.

Technically, demultiplexing converting the file and then remultiplexing is a way of decoding and re-encoding. That would take you forever. Using MPEG VCR or ImToo doesn't require re-encoding and should take a few seconds per file to re-sample.

I will say this, what concerns me most is, if I take and down-sample my files now... when VDJ supports upsampled files, I may feel that I have an inferior file and go about reloading everything again... Just food for thought.
 

发表时间 Mon 02 Jan 06 @ 6:05 am
I am using a MAYA 44MKII sound card. I have no lag issue.
I am hearing a difference in how the sound quality is between 44 and 48 though.

I am still experimenting with my set up to make it optimum for video mixing. I am buying a new video card to help with my slow FPS while using two video streams and scratching using the TCV. I am buying the GeForce 6800GT 256 MB card. I have found that using the Nvidia PureVideo Decoder helps with that too. Now I am not sure if it will help with the audio issue. I would love to not have to resample all my audio to 44khz. Just trying to find the easiest way if I have to.
 

发表时间 Mon 02 Jan 06 @ 12:09 pm
@ Low-fat-al: When you play a file that is 48k vs 44, are you playing it using the internal decoder? Vob, for example, needs to be played with an external decoder (The windows media player one). This last Friday, I took and played vobs rather than mpegs and was concerned that there would be video lagging behind the audio. The audio, as I remembered, didn't sound bad at all. When I did this on Friday, the audio (at 48k) sounded fine and I was surprised to find that the videos didn't lag noticably (if at all). Consequently, I didn't have to downsample because it is the VDJ decoder that has problems with 48k, not my internal stuff.

 

发表时间 Tue 03 Jan 06 @ 12:15 am
I will experiment some more and try to use the external decoder when I get my new video card and see if that made a difference... like I said before.. I DON'T want to have to resample all my video files. BTW.. I am using MPG files not the VOB's.. it is ripped using the same method as smartripper just different software is all.
 

发表时间 Tue 03 Jan 06 @ 12:20 am
clayPRO InfinityMember since 2005
Tonight was the first night for me at the club with the new PC & VDJ.

Some videos there was no noticable lag, others there was PLENTY of Lag. Not sure why some performed better than others. I used Smartripper for Promo Only discs, ripped as VOB files.
I've got a Asus 7800 GT video card and a M-Audio Delta 44 soundcard. The quality of the video is great. The audio seems to be fine for a bar (could be better). The video/audio delay is better on some videos than others.
For example, Gwen Stephanie's Hollaback Girl was Terrible, whereas Sir Mix a Lot's Baby Got Back was dead on.
Not sure. Mods if you are even reading this..or if you even care that I spent 3 Grand building a PC specifically for your software, and was told VOB's are great (as per Cyder) but MADE NO MENTION OF ANYTHING LIKE THIS. I have to learn AFTER THE FACT.. and that IS A REAL PISS OFF.
90% great, 10% really crappy.

What now?


 

发表时间 Tue 03 Jan 06 @ 9:45 am
clayPRO InfinityMember since 2005
OK night number 2 with the new show. Tonight was worse. Maybe my ears were being more critical tonight, but there is a noticable difference between my standard CD's audio quality and the audio from the VOB files at 48mhz.
AND the timing of the audio/video was so off that people actually came up to the booth to ask me what was wrong with the videos!
This is extremely frustrating for me, and I'm starting to think that I just might of wasted a LARGE amount of time and money in something that isn't doing at all what I thought. I read hundreds of threads on this website before I made ANY purchasing decisions. I exceeded the reccomended PC specs by a LONGSHOT. I bought a legitimate copy of the software off the VDJ site. I have waited patiently for ANY actual technical support from VDJ, or even a glimmer of hope that somebody ANYBODY is working to resolve these problems on the software.
The audio plays without hesitation, but the video may pause for a second, time delays on VOB files, bad audio quality from the VOB file even using an external decoder.
I'm gonna turn this PC into a personal gaming box, eat the money I spent on the software, and forget anyone ever told me that this could be done.
UNLESS anybody at VDJ will take two seconds out of their day to respond to this and tell me that they are working on it, and I should See results in the not-too-distant future.

Clay
 

发表时间 Wed 04 Jan 06 @ 9:55 am
man.. I don't want to get to that boiling point...
that is why I just converting the audio to 44khz now... so I don't have to wait for anybody on the tech team to say, "WE GOT IT!!"... because that may never happen.

Clay... you should just resample your audio to 44khz and run a test... I imagine it will work. just sucks how time consuming it is.
 

发表时间 Wed 04 Jan 06 @ 10:06 am
clayPRO InfinityMember since 2005
Hey Low-fat-al!!

Sorry, just needed to vent.

Can you give me details as to exactly what I need to do to re-sample the audio?
What program did you use, how did you do it?

All my videos are straight off Promo Only DVD's ripped with SmartRipper as VOB files.

I appreciate your assistance VERY much!!

Clay
 

发表时间 Wed 04 Jan 06 @ 9:31 pm
well the steps are plenty and time consuming...

First if you want to keep from re-encoding the video you have to demux the streams.. meaning you have to split apart the audio and video streams so they are seperate. To do this you should use TMPGEnc. It has MPEG Tools that allow this function. Next bring in the audio into something like Sound Forge were can do the neccessary changes to resample the audio. Under "Process" on the top menu is resample. There you must resample the audio to 44khz. You can by the way normalize the audio and do any other changes you need to while having in Sound Forge.. JUST DON'T CHANGE THE LENGTH!! Save the audio as an MP2 audio stream... whatever bitrate to your liking.. I usually do mine at least 192k. Next you have mulitplex the two streams back using TMPGEnc. The final result will be a MPG file playable in VDJ!! With this method you haven't touched the video at all. That is way I do it anyways... someone else on this forum may do it different. Good luck!!
 

发表时间 Wed 04 Jan 06 @ 10:15 pm
clayPRO InfinityMember since 2005
thank you!

I will try it.
 

发表时间 Fri 06 Jan 06 @ 1:17 am
Guys I have a way of changing Promo Only Vobs from 48Khz To 44.1KHz audio without altering the video, that's much easier, but as yet I have not found any way of multiplexing a MPEG2 and a 44.1Khz LPCM (wav) file. I can only encode the audio and mux it to mp2, which isn't bad anyway, as it reduces the filesize and you can encode to 384kbps. I first rip the vobs with DVDDecrypter. This is how I convert the vobs afterwards:

1. Buy TMPGenc MPEG Editor
2. Set it up
3. Start the program then go to it's "option" settings (right hand top corner)
4. Select "preferences"
4. Under the Pref. 1 tab set your output file as the folder you want all the videos to finish up.
5. Under the default output tab select your output target as Common MPEG File
6. Under the default output tab tick the "Always re-encode the audio to the format below"
7. Select your audio output to MPEG-1 Audio Layer II, 44100, Stereo, 384.
8. Press OK.
9. Uner the project menu selct "Start New Project"
10. Add A File or just drop and drag your vob to the window.
11. When it comes up with "File bearing a VOB extension can not be read "as is" select yes.
12. An "Add Clip" window pops up. This is to allow you to cut/edit the video if you wish, but we're not going to bother. Just press OK.
13. You're back to the main window. Select "output" up the top, and the window changes to output mode.
14. Simply press "Batch Register" in the bottom right hand corner. This opens the batch window.
15. Press start on the main window then to add another clip to the batch go back to step 9.
16. Once you have all your files in the batch press "Start Batch" on the batch window.
17. Try one or two vobs out first to make sure the new file works well and is compatible on your system.

I have two "gig" PC's. One plays these files well while the other has lagging and skipping in the video on screen. The only difference between the two machines is the motherboard and the fact that one has Windows separate on a 10,000rpm drive. the specs are as follows:

3400+ (754)
1GB Corsair 3200ll XMS RAM (2 x 512mb)
GeCube X800pro (I keep all desktops and video outputs to 1024x768 60hz)
"Good Machine" : Windows on WD Raptor 36Gb 10,000, Videos on WD Caviar SE 250Gb (8mb Cache)
"Bad Machine" : Windows & Videos on WD Caviar 250Gb (2mb Cache)
"Good Machine" : Gigabyte GA-K8NS Pro nForce3-250
"Bad Machine" : ASUS K8V-MX VIA K8M800

Even on the good machine the frame rate drops a bit on fades sometimes (hardly ever, but it does happen so I won't state that it is PERFECT), it's hardly noticeable and it definately does not alter the audio output, which is seamless. I use the internal decoder for all videos. Once you have encoded the audio of all your videos once, you won't have to do it again and the quality is well and truly good enough not to bother ripping all your vobs again when a 48k solution is found by the dev team.
 

发表时间 Thu 26 Jan 06 @ 4:17 am
acw_djPRO InfinitySenior staffMember since 2005
AussieDJ,

Thanks for the input. It's very useful information.

You config seems ok, but what is your current Video Card for each system? I think the problem is there.

 

发表时间 Sat 28 Jan 06 @ 9:09 pm
Thanks for the great info, I was struggling with the audio now it sounds great.
 

发表时间 Fri 24 Feb 06 @ 9:03 pm


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