Forcing the frame rate to 29.970fps when the capture is not

[FulciLives]

Hello !

I've been using a PCI TV tuner type capture card (the AverTV Stereo).

I've been using VirtualVCR to do my captures and trying the dynamic audio resampling method of A/V sync.

This seems to work MOST of the time but sometimes the audio sync is off. The most annoying thing is that it will be off and on ... for instance it will be dead on and then creep a bit for a short time and then get back in sync and over again.

Originally I used iuVCR to capture using the AUDIO as the master stream. This always seemed to work except my final FPS would never be exactly 29.970fps but always something very close (like 29.964 or 30.041 etc.)

So I've been sticking to VirtualVCR since it does give me a rock steady 29.970fps for the video.

However ... I Recently got pissed off about the sometimes out-of-sync audio so I tried FlyDS which seems to work the same as iuVCR as you set the AUDIO as the master stream which seems to keep sync but gives you a final FPS that is usually not exactly 29.970fps

So I got to thinking ...

What if I use the following AviSynth command:

AssumeFPS(29.970, true)

So I put that in my AviSynth AVS script and guess what ... it seems to work. So far I've only tried it with two long captures (both from VHS about 90 minutes each) and it stays in sync (as per the original capture) but I can use CCE to encode (whereas before I had to use TMPGEnc because of the odd FPS number).

One capture was 29.966fps and the other was 29.953fps

I actually run the AviSyth AVS script twice. Once through CCE to do the VIDEO and again through TMPGEnc to get LPCM audio (which I then normalize in a WAV editor and then convert to AC-3 audio).

Anyone have any comments on this method i.e., is it somehow BAD or WRONG to do this?

So far I'm tickeled pink that it is working since I don't feel I need to blow my wad on a Canopus ADVC-100 just to get perfect A/V sync (and I didn't want to deal with the 4:1:1 vs 4:2:2 color thing either).

- John "FulciLives" Coleman

P.S.
Here is the exact AviSynth AVS script I used for my last project using this method:

LoadPlugin("mpeg2dec3.dll")
LoadPlugin("convolution3d.dll")
avisource("D:\capture.avi")
Trim(518,149033)
AssumeFPS(29.970, true)
crop(0,4,0,-12)
SeparateFields()
Convolution3D (0, 6, 10, 6, 8, 2.8, 0)
Weave()
AddBorders(8,8,8,8)

Original capture was at 704x480 and I had to trim 12 off of the bottom to cut off that VHS garbage you get then I always like to trim a couple lines from the top as well (just in case there is garbage there although it never seems to look like there is) and then I used the AddBorders command to add black (to bring it from 704 to 720 for the width and then I center the image with equal black dead space on the top and bottom so I'm back at 480 for the height).

[ronnylov]

I use the assumefps(25,true) to convert from NTSC to PAL and it works when converting from 23.976 to 25 fps without audio sync problems. When I use this method I make sure using wav file as audio instead of compressed format. One thing that is good to know is that the sampling frequency of the output is changed to keep the audio in sync with video. So when you encode this avisynth script in tmpgenc it will resample your audio before compression. I use an external sample rate convertor called ssrc in tmpgenc because I know this one is very good in quality.

Have you tried VirtualDubSync? This software will resample the audio in real time (by using ssrc resampling) to keep sync with video without dropping frames. It will do the same thing as your method but in real time. I have tried it and for me virtualdubsync caused dropped video frames (probably too cpu demanding).

I use AVI_IO to capture. I always get perfect sync with avi_io but with the cost of some dropped video frames to keep video in sync with audio. Your method seems to bee a good way to sync the audio with the video without dropping video frames.

[Gazorgan]

Dam, nearly Identical to what I use. And yes, the same problems.

I use an AVI framerate conversion utility. I'm at work, so I can't remember the name, but it has the same icon as the 4cc changer on my toolbar. I've had excellant luck with captures in the 29.90 to 30.02 range. Most are 29.965-29.975 range from IUVCR. No sync issues in my typical 1 hour TV captures, after clipping out commercials(in vdub).

[dcsos]

Premiere has a RESAMPLE routine when it senses the input video is a certain frame rate, and you dial up a different output cadence (ie 29.97 from 30 fps input) it just properly resamples to the new rate, allowing one to
chooze field prefrence and pixel shape as well..
Wouldn't this be easier?..
(It'll also add frames as in coming from 23.7 PAL to 29.97 US)

[FulciLives]

I use the assumefps(25,true) to convert from NTSC to PAL and it works when converting from 23.976 to 25 fps without audio sync problems. When I use this method I make sure using wav file as audio instead of compressed format. One thing that is good to know is that the sampling frequency of the output is changed to keep the audio in sync with video. So when you encode this avisynth script in tmpgenc it will resample your audio before compression. I use an external sample rate convertor called ssrc in tmpgenc because I know this one is very good in quality.

Have you tried VirtualDubSync? This software will resample the audio in real time (by using ssrc resampling) to keep sync with video without dropping frames. It will do the same thing as your method but in real time. I have tried it and for me virtualdubsync caused dropped video frames (probably too cpu demanding).

I use AVI_IO to capture. I always get perfect sync with avi_io but with the cost of some dropped video frames to keep video in sync with audio. Your method seems to bee a good way to sync the audio with the video without dropping video frames.

Well I can't use that mod of VirtualDub for capture purposes since my capture card uses a WDM driver which pretty much makes VirtualDub anything worthless for capture.

I have never tried AVI_IO so maybe I will give it a chance but I must admit that I am rather happy so far with FlyDS because it seems to work just like iuVCR but offers a very easy-to-use and easy-to-read AUDIO LEVEL METER that makes setting the AUDIO INPUT LEVEL a breeze.

As for the audio in TMPGEnc I have it set to HIGH QUALITY (SLOW) in the ENVIRONMENTAL SETTINGS.

Would I be better off to link to SSRC? I thought SSRC was only for doing 44.1k to 48k conversions etc.?

- John "FulciLives" Coleman

[FulciLives]

Dam, nearly Identical to what I use. And yes, the same problems.

I use an AVI framerate conversion utility. I'm at work, so I can't remember the name, but it has the same icon as the 4cc changer on my toolbar. I've had excellant luck with captures in the 29.90 to 30.02 range. Most are 29.965-29.975 range from IUVCR. No sync issues in my typical 1 hour TV captures, after clipping out commercials(in vdub).

Glad to hear that my solution is something that actually works and seems to be a decent solution to audio sync VS proper frame rate.

Would still be interested to hear what AVI framerate conversion utility you use but I'm so far happy doing it with AviSynth since I'm using AviSynth anyways for other things such as the Convolution3D filter.

- John "FulciLives" Coleman

[FulciLives]

Premiere has a RESAMPLE routine when it senses the input video is a certain frame rate, and you dial up a different output cadence (ie 29.97 from 30 fps input) it just properly resamples to the new rate, allowing one to
chooze field prefrence and pixel shape as well..
Wouldn't this be easier?..
(It'll also add frames as in coming from 23.7 PAL to 29.97 US)

Sounds interesting but I don't have Premiere nor do I want to invest that kind of money. I mostly just capture movies and TV shows which require just simple editing such as trimming the start and end and cutting out TV commercials when they are there. Seems to me that Premiere is really something that is OVERKILL for all that.

Plus my captures are sometimes HuffyUV and mostly PICVideo MJPEG (19 quality settings) and I thought Premiere was more for DV editing?

- John "FulciLives" Coleman

[FulciLives]

I've just realized that TheFlyDS capture program is not listed in the TOOLS section of this website so here is a link to it:

http://www.asvzzz.com/index.htm

I think it is a GREAT capture program

- John "FulciLives" Coleman

[dcsos]

If you have a CODEC properly intalled PREMIERE will see it and allow you to edit with that format on its timeline whatever it may be..
I know PREMIERE's expensive and don't get me started about the newer
BUGGY PREMIERE PRO that only goes on XP they just put out

Perhaps a bundled with capture version might come your way as the LIGHT version has the frames reample function built in.
Reading with interest about your method tho'

[FulciLives]

If you have a CODEC properly intalled PREMIERE will see it and allow you to edit with that format on its timeline whatever it may be..
I know PREMIERE's expensive and don't get me started about the newer
BUGGY PREMIERE PRO that only goes on XP they just put out

Perhaps a bundled with capture version might come your way as the LIGHT version has the frames reample function built in.
Reading with interest about your method tho'

That reminds me I have a version of Ulead VideoStudio 7 that came in some package I got.

I wonder if that does the same sort of thing that you are talking about in regards to Premiere?

I don't suppose you would know

- John "FulciLives" Coleman

[vhelp]

Fulci,

I'm not familiar w/ ivVCR or whatever it's call :P
but, I know that vdub has two areas to input fps. And, if you go through
the settings windows, you'll never get a locked fps, and it will fluctuate,
probably to stay w/ audio or something.
.
.
But, if you use the button at the bottom right, and selet your desired fps,
it will always stay at ie, 29.970 fps w/out probs.

I'm glad you found an alternate method for your audio sync issues though :P

-vhelp

[ronnylov]

AVI_IO use the same type of video-for-windows drivers as virtualdub. I have an ATI AIW Radeon card with wdm drivers only, but I use the vfw-wdm wrapper which enable capture in vfw software like virtualDub and AVI_IO. AVI_IO has built in audio level meter so it's also easy to set up correct level.

ssrc (shibatch sampling rate converter) is freeware and can be set up as external resampler in TMPGEnc environmental settings. I don't know how it compares to the internal resampler, but I've heard that ssrc is a very good and fast resampler so I use that. Yo can get it here: http://shibatch.sourceforge.net/

Some info regarding the VfWWDM wrapper: http://www.doom9.org/index.html?/capture/capturing.html

Here is some info how to set up the wrapper in Win2000: http://www.virtualdub.org/docs_vfwwdm

EDIT: Now I have read some about wdm and vfw capture and I may reconcider and start using a capturing program that uses wdm directly. Here is what microsoft say about it: http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dndevice/html/vidcap.asp

[dcsos]

That reminds me I have a version of Ulead VideoStudio 7 that came in some package I got.

I wonder if that does the same sort of thing that you are talking about in regards to Premiere?

YES it does..
ULEAD Should fix you up just fine..with one resriction..quick time
and all I remember is Quick Time Movie codecs were not displayed properly in ULEAD but all the AVI choices showed up (HUFFY & DIVX & XVID..and working in ULEAD now)

[Gazorgan]

It's AVIFrate located here: http://www.am-soft.ru/avifrate.html

It's been essential for me because IUVCR never hits a framerate exactly. Great for splicing AVI capture segments also.

[dwiesel]

A PAL / NTSC issue that has me confused...

I live in the US...in getting non-US region DVD's (that are also PAL), I use software to remove the region-code and can copy/play the DVD in my player (without manually having to convert PAL to NTSC). Great, fine.

What I have noticed is, the AUDIO PITCH IS TOO HIGH (i.e. plays too fast), thus (logically) so is the video too fast. Is this symptomatic of playing PAL DVD's on NTSC systems? It's terrible. Can this be "fixed" by some kind of manual PAL to NTSC conversion?

The botton line is, the audio pitch is too high...if converting won't help the speed, I'll go as far as stripping out the audio and lower the pitch using some software and then mux it back with the video. Is there a standard/simple solution here?

Thanks.

[FulciLives]

A PAL / NTSC issue that has me confused...

I live in the US...in getting non-US region DVD's (that are also PAL), I use software to remove the region-code and can copy/play the DVD in my player (without manually having to convert PAL to NTSC). Great, fine.

What I have noticed is, the AUDIO PITCH IS TOO HIGH (i.e. plays too fast), thus (logically) so is the video too fast. Is this symptomatic of playing PAL DVD's on NTSC systems? It's terrible. Can this be "fixed" by some kind of manual PAL to NTSC conversion?

Thanks.

Well the problem is that PAL runs at 25fps whereas film is 24fps. Now NTSC video be it progessive 23.976fps or interlaced 29.970fps actually has the same playback speed as film aka 24fps but since PAL is 25fps the film it played back at 25fps

Now 1 extra frame per second doesn't sound like much but that is a 4% speed increase ... 24fps ---> 25fps = 4% speed increase

This is the PAL format. People who live in PAL countries and play back PAL DVD discs on PAL DVD players on a PAL TV still have 25fps with the 4% speedup.

So the problem is with the PAL format.

Now most people cannot notice the pitch shift that happens from 24fps to 25fps but some people can notice it. I guess it just depends on your hearing and pitch level. If you are a musician it might be more noticeable to you for instance. Also if the PAL DVD is mostly music like a concert or musical etc. then the pitch shift, because of the music, might be more noticeable.

Anyways a DVD player that converts PAL to NTSC does so in such a way so that the new NTSC output matches the audio. So no change is being done to the audio.

Now if you do it on the computer you can convert the PAL source (well most PAL sources anyways) back to 23.976fps progressive NTSC and also slow down the audio.

But even then some people complain about the pitch shift.

Anyways for more info on this you might want to read the following thread:

https://www.videohelp.com/forum/viewtopic.php?t=160433

- John "FulciLives" Coleman

[dwiesel]

John, you are the man...thanks for the enlightment! I will get to that thread tomorrow, and will somehow get the audio correct. Nothing's simple is it. 8)

Thanks again, Dave

[DaveS]

It's AVIFrate located here: http://www.am-soft.ru/avifrate.html

It's been essential for me because IUVCR never hits a framerate exactly. Great for splicing AVI capture segments also.

Ivan says uncheck the master stream and it will hit the frame rate....not sure if this then allows the drift to creep in

[Loader]

I need to pass a NTSC dvd to dvd PAL but the NTSC is at 29.970 FPS and when i put the sound to 25 FPS the sound is like a robot can anyone help me please.

Sorry about my english.

[FulciLives]

I need to pass a NTSC dvd to dvd PAL but the NTSC is at 29.970 FPS and when i put the sound to 25 FPS the sound is like a robot can anyone help me please.

Sorry about my english.

Go to the GUIDES and look up the PAL<--->NTSC guide by Xesdeeni

- John "FulciLives" Coleman