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  #1  
08-01-2015, 03:38 AM
Guessed Guessed is offline
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I don't post much anywhere so please forgive.

My hardware is: AIW 800XL AGP, E4600 C2D @ 2.4, 2GB RAM, SB X-Fi, 2 HDD for OS & to save to, all on an
ASRock 4CoreDualVSTA with Via chipset

: JVC HR-S7500U (TBC really helps clean things up)

- I dont have anything OCed and is stable with APG @ 8X but I keep it on 4X

My situation is I am capturing VHS and have used the guides on this site with the settings suggested in them, resulting in good captures proportional to the original sources. I want DVD copies so I have used the MPEG guide, done multiple captures at different bitrates (as I learn) around the suggested rate of about 3000-3500kbps target, up to around 7000kbps. I know it says anything over about 4000 is just a waste of bytes with diminishing returns, but I figured if it is any better at all then its fine, as long as it fits on a disc, a burnt disc is a burnt disc and I dont care if it takes longer to burn. I captured using MPEG2-DVD
in MMC using the Cropping option sometimes when needed to get rid of distortion at the bottom.

I then decided to give AVI captures a try, again using the guides here (Thank You) with MMC and HuffYUV multi-thread. It captured great and could definitely see the improved quality. Even with a very poor quality source tape I captured its 90 minutes with only 5 dropped frames and the CPU utilization was only at 10%, similar to earlier MPEG captures, so hardware is not an issue. I was just surprised that I could capture at 10% CPU utilization but it went up to about 40% during playback, since I thought both were software based being AVI.

Anyways, I then tried to capture AVI (always using the same source tape as above) in VirtualDub instead of MMC due to its reputation and to be able to use its filters and features like cropping. The problem is, unlike with MMC, no matter what settings I change it drops frames terribly, 15-20%. The longer the capture the worse the frame dropping gets. In only 5 min of capture I can be down to about 23fps instead of 30. I am pretty sure that even though this happens, the CPU usage still stays at about 10-15%. Even when not capturing, the preview/overlay window drops frames and skips after a while and gets worse the longer it goes.


I am looking for feedback on possible reasons/settings in general or within VirtualDub that may be causing this with the hopes of being able to use it.


Also, when I capture MPEG for DVD, 90-120 minutes is about 3-4 GB, which is fine for that purpose. But I would also like to give people a copy of the same captures for storage and playback on their computer, in a decent 4:3 resolution and format, with a codec/container that a Windows based computer with relatively basic common software would be able to play back, and have smaller file size of about 500MB-1GB.
What are the best options, and how do I get there, in steps.

Sorry for the length, but thanks for any help.
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  #2  
08-05-2015, 03:22 PM
sanlyn sanlyn is offline
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Quote:
Originally Posted by Guessed View Post
I would also like to give people a copy of the same captures for storage and playback on their computer, in a decent 4:3 resolution and format, with a codec/container that a Windows based computer with relatively basic common software would be able to play back
Any computer can play MPEG. If you're thinking of something like h264 encoding to get a somewhat smaller bitrate, remember that re-encoding lossy formats like MPEG is a quality loss, and h264 doesn't handle interlaced video as cleanly as MPEG (we nit-picky geeks can see a difference, but many viewers can't). You can try h264 encoding in mp4 containers which is fairly common, but many versions of software like Windows Media Player don't handle aspect ratios correctly with many containers. 4:3, by the way, is an aspect ratio, not a "resolution". MP4 containers can also contain video resized to 4:3 proportions and encoded for square-pixel playback.
You can avoid re-encoding degradation by capturing to lossless media, which can be the source for any kind of encoding and format you want for delivery afterwards.

How old is that 7500 VCR? If it's had no maintenance in a long time, you likely need a frame-level tbc to help maintain proper frame speed without dropping frames and to correct for unstable playback with worn belts, capstans, and other parts. You need the line-level tbc in the 7500, but it's not a full-frame tbc for frame timing. Dropped frames are also called by resource-hungry antivirus apps, especially if your a/v likes to work system scans while you capture. Capturing to the same hard drive that houses your OS is another cause. Other than those kinds of problems, you might let us know how you've set up VirtualDub for capture. For most people, the defaults except for capture size and compression usually work OK

Cropping head-switching noise off the bottom of the frame isn't the way to handle the usual head-switching noise. It should be masked with black border to retain the proper frame size without added resizing and altering the playback aspect ratio. Cropping is fast but it does take time and CPU; it likely wouldn't affect lost frames, but it's possible. Most people when capping to losslss AVI leave the borders as-is and fix them in post-processing without altering the original image porportions.

Capturing analog tape to MPEG isn't the cleanest way to do it. It depends on the final quality you want. MPEG is a final delivery format, not an editing format. 4GB for a 90-minute MPEG is about right if you keep a decent bitrate and use variable bitrate with 2-pass encoding. Action video requires more bitrate than video that seldom moves. VHS noise also eats up more bitrate.

You can reduce a 4GB MPEG to 1 GB or so with these steps:
a) reduce the frame size. This means deinteracing, resizing, and reintelacing. If your recordings are movies, they're likely telecined, which can't be deinterlaced. Apply inverse telecine instead.
b) Reduce the bitrate appreciably when re-encoding by abou8t 50% or more.
You can expect substantial quality loss by reducing an original video to 25% of its original data content, especially without cleanup of the source.
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08-07-2015, 01:58 AM
Guessed Guessed is offline
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Sanlyn, thank you so much for your response, I really do appreciate it. I was beginning to think no one would, just because I have only posted something anywhere about 4 times now over the years and no one ever has replied. Do I have to do anything specific to add to your Thank You count?

I really am a beginner at this and anything software based (more interested in hardware), and although I try to read about stuff, I am not a reader by nature so I find it difficult to learn when there is a lot of reading involved to get there.

Anyhow,

All my software setups in both MMC and VD are very much in accordance to the suggested ones given by LordSmurf in his guides on this site since I really dont know what I am doing and am not a big experimenter. That is why I cant understand why MMC will capture AVI with absolutely no problems and VD is nothing but dropped frames. I am using MMC 9.08 because my x800XL doesnt want to be detected in 9.02 and earlier for some reason, although I dont seem to be having any probs with 9.08. I am also trying to use VD v1.9.11 (with filters) from this site, with only the basic default suggested settings changed.

I am using a clean basic Windows XP install with no AV, nothing extra except necessary drivers and MMC & VD. OS is installed on one HDD and captures saved to another.

I bought my 7500 brand new years ago but it has had very very little use over the years. I dont have the money or extreme quality concerns for an external TBC. I have to do my best with what I have now.

The distortion I am getting is a small uniform strip from one side to the other on the bottom only, which I am assuming IS head-switching noise that you mentioned. Although it is not optimum like you said, I used the Cropping option in MMC to get rid of it, which for me would suffice to get rid of it in a worse case scenario even if it changes the resolution slightly and distorts or stretches during direct MPEG captures.

Stupid ? but is 2-pass encoding something other than default capture in MMC Mpeg or a setting I dont see?

As mentioned in my first post I captured the desired video also in AVI (not cropped) with MMC with great clean problem-free results. I can use it as the source to create my desired <1GB computer based files for distribution, and also to convert it to MPEG doing 2-pass encoding if different than MMC direct MPEG2-DVD capture. I did direct MPEG2-DVD capture also because I read to just do MPEG directly rather than the time and effort from AVI source.

For my <1GB files I was thinking of just decreasing the resolution and bitrate and use MPEG again to keep things easy form my the sake and for easy compatibility playback. I read this topic ..... http://forum.videohelp.com/threads/221030-Film-captured-(Huffyuv)-now-how-to-convert-it-to-DivX
but was wondering if it is worth my trouble. Is PCM audio compressed in MPEG or just video? Would Xvid and MP3 in an MP4 container be much smaller and worth the trouble for my inexperienced self?

Sorry for another very long post, and again Thanks for any response.
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