old vhs restoration

[ishwinderjauhar]

hi
i was trying to restore some old vhs recordings and was facing the following problems-
1. White line on the right side of the picture
2. a lot of grain
3. colours appears bad
4. wierd lines appearing at different times, colour lines.

I am using adobe premiere and after effects for editing.
If i use the premiere filters to reduce noise then the picture appears very soft on the television.
Deinterlacing mpeg 2 files also is not having the desired effect.
can you please go through the video attached and give suggestions as to what steps/filters i can undertake

[jagabo]

The bright vertical line can be largely fixed by an overlay. Before on top, after on bottom:



A little more tweaking should be able to do even better. I used this in AviSynth:

src=Mpeg2Source("02.d2v", CPU=2).ConvertToRGB()
fix=ImageSource("sub.png").RGBAdjust(r=1.1, g=1.1, b=1.1)
StackHorizontal(src,Overlay(src, fix, 0, 0, mode="subtract", pc_range=true))

I didn't see any problems with deinterlacing. What problems were you seeing?

[magillagorilla]

Some chroma smoothing or chroma noise reduction will get rid of most of that yellow splotching in the light area and purple grain in the dark areas.

[ishwinderjauhar]

any good link as to how to deinterlace, i saw the procedure on 100fps.com, did not get it... i think i am doing it wrong.
i'll try the overlay and get back to you
thanks

[magillagorilla]

Use AVISynth to fix chroma and deinterlace. It will do a way better job than an NLE. Almost all of your noise is chroma noise. Don't try to remove all the grain. It's vhs and grain is what makes the image. Too much smoothing will make your footage look fuzzy or plastic.

My favorite deinterlacer is QTGMC(slower, sharpen=1) If your goal is computer playback only, keep both fields. The resulting video will be double frame rate, 59.94fps (NTSC source) or 50fps (PAL source). This is the best looking way wo deinterlace VHS in my opinion. You eliminate interlace lines and retain your temporal resolution. It's very slow but clean.

One of my favorite chroma smoothers is in Virtualdub called camecorder noise reduction. This filter knocks out most color splotching and bleeding.

[jagabo]

If you're going to DVD there's no need to deinterlace. DVD and televisions fully support interlaced video. If you're going to upload to Youtube or some other video sharing site you'll want to deinterlace.

[jagabo]

A better VCR will probably clean up a lot of the tracking problems. Look for a SVHS deck with a line TBC.

A simple fix for getting the audio in both channels is using a Y adapter cable to split the mono output from the VCR to the capture device.

MergeChroma(last, McTemporalDenoise(settings="very high", interlaced=true))
before/after:


For MPG files use DgMpgDec to deblock. Build and index with DgIndex then open the file via Mpeg2Source("filename.d2v", CPU=4) in AviSynth. That will give you good deblocking. You can get deringing too (this video is too blurry for ringing to be a problem) with CPU=6. The above image was done with deblocking (though it was saved as JPG at a low quality setting so some blocks have come back).

[magillagorilla]

Good chroma cleaner Jagabo. I'll have to try that.

Is the footage being captured to your computer from VHS>MPEG? You should capture to a lossless AVI format if you can, like Huffyuv. Your post processing will look much better. Blocking will be a non-issue in lossless. Plus if you keep the video in the YUV color space you may have more control over color levels and chroma as YUV is like the native VHS signal. Really the color isn't that bad, it's a bit green. Maybe Coloryuv(Autolevels=true, Autowhite=true) would help. My syntax may be a bit off. Some people aviod the "auto" settings. I find it works well in a lot of footage.

Like Jagabo said, if you are going back to DVD, don't deinterlace. I choose to restore all of my footage to progressive as I don't plan on using the DVD format in the future.

[sanlyn]

A better VCR will probably clean up a lot of the tracking problems. Look for a SVHS deck with a line TBC.

That's best, but good luck finding one. A DVD recorder as pass-thru is your next best bet.

A simple fix for getting the audio in both channels is using a Y adapter cable to split the mono output from the VCR to the capture device.

It works, but the result sounds rather flat and dull. I had this problem with an opera project, which jagabo might recall. Got better results with free audio program Audacity (http://audacity.sourceforge.net/). First, save audio-only from the video as uncompressed .wav. Instead of using the simpler "make tracks mono" command (that's the same as using a Y-adapter), first make the two tracks mono instead of stereo. The interface will show two tracks, one with audio and the other blank. Then copy the whole "good" track, paste it over the empty track, and make the audio "stereo" again. Then save the new stereo version to .wav. It will still be mono technically, but richer with better dynamics. I read somewhere that the Y-adapter trick does something to the phase and dynamics in the original audio that makes it sound pretty tepid.[/QUOTE]

MergeChroma(last, McTemporalDenoise(settings="very high", interlaced=true))

jagabo suggested this earlier in another thread. If you have badly faded video that develops horrible chroma noise and weird color when you pump up saturation, this trick does a nice job. Thanks, jagabo.

[jagabo]

A simple fix for getting the audio in both channels is using a Y adapter cable to split the mono output from the VCR to the capture device.

It works, but the result sounds rather flat and dull.

Hmm. I never had that problem. You may get a -3 dB reduction in volume though.

The OP should be aware that there may be two audio tracks on a VHS tape. A low-fi mono track and a high-fi stereo track. Always use the stereo track if the tape has one, it will sound much better. Of course, you need a high-fi VHS deck to get that track.

[sanlyn]

Volume stays the same with that Audacity method (no volume loss or gain this way, but it will sound "louder"). No change in file file size, either (I have no idea how that works!). As I understand it, splitting the signal has detrimental "phase effects", parts of the original channel cancelling the other on playback. It's not just a volume loss on each channel. If you have an amp or preamp with a mono switch, you can hear something of that dulling effect thru speakers. Wish I had that ancient mono-stereo article around from Stereophile magazine, but basically that's what I recall.

The phase change can be heard if you have an FM tuner. Find a noisy FM stereo station with static, etc. Tune the station in mono if your tuner lets you, or switch your amp to mono. Much of the high-frequency hiss and some static recedes into the background. It's all still there, but the inter-channel phasing has changed.

[magillagorilla]

Sanlyn, you are mostly correct. When going Stereo > mono you may not want to just combine the cables. Depending on how the stereo was created you could be dulling some frequencies while boosting others. You can run in to the reverse phase cancellation issue like how those active noise cancelling headphones work. Conversely, if the two channels contain sympathetic frequencies you could get frequency amplification or new frequencies that were not there before (harmonic distortion). But if the stereo has discrete sounds in either channel, think late 60 recordings where the bass guitar is entirely in the left channel and the guitar on the right, your method of mono would eliminate valuable data.

However, mono to stereo (2 channel mono) does not suffer from this problem. You are merely replicating 1 signal in to 2 channels. The only variance is that you have devided the voltage and may experience a drop on db level, this is easily corrected. Since the mono source does not contain two competing signals, phase cancellation is not possible. All of my VHS camcorders were mono. Splitting the output with a Y connector to a stereo recorder works fine.

[sanlyn]

All of my VHS camcorders were mono. Splitting the output with a Y connector to a stereo recorder works fine.

On the project I mention, the signal was recorded as "stereo" by a dvd recorder. Whether the VCR or the dvd recorder had a dead channel or what, I don't know (not my recording). But only the right channel has audio. You can tell the source was supposed to be stereo, as it's a live stage recording and you often hear a voice get lower (and what appears to be slight echo or reverb from the missing channel) when a character moves to the left side of the scene.

Some years back I heard of a software/hardware package that could analyze phase info if one channel was missing, and work a mix that "rebuilt" the missing track (limited separation). It cost $4K USD back then. No telling what it costs now.

[magillagorilla]

My levels are off and I accidentally rendered it 720x480, oops. Anyway those chroma splotches that were bothering me are gone and the footage deinterlaces well.

[pirej]

I tried one of the scripts i have used before on bad vhs, but i dont have time to tweak anything..
The script is powerful and slow (0.79 fps), but this vhs(mine too) is in VERY bad condition.

[magillagorilla]

pirej, nice script, any chance of sharing it? You are able to mask a lot of that traccking, horizontal noise. I'm not all that great with color. I always tend to desaturate and lean towards cool whites. That's just what is comfortable to my eye.

[jagabo]

pirej, nice script, any chance of sharing it?

The link is in his post.