View Full Version : Help with capturing PAL VHS and upscale to to 720p
RainbowThief
17th July 2020, 12:38
The original video masters to two shows have been lost, all I have are PAL VHS ex-rental tapes which I need to convert for use as extras on a Blu-ray release. The original (lost) masters were shot in the PAL format in 1982.
I'm considering upscaling to 720p / 23.976 fps for this.
Any suggestions as to the best way to go about this?
I guess it would be via an S-VHS deck with TBC. I'm unfamiliar with AviSynth, so would need help in setting this up and scripting - or I guess I could use the MeGui option.
I've experimented so far by recording to high-bitrate DVD-R and ripping with HandBrake and forcing the frame rate change from 25 to 23.976. As there's very little on-screen movement it looks pretty decent (it's a stand-up comedy show). I was wondering how I could get better results?
I'm a Mac user, but I also have a Windows 7 PC for authoring Blu-ray discs.
Thanks,
Sharc
17th July 2020, 12:57
My first thought is why you would want to convert (framerate and format) the PAL footage? PAL 720*576i25 is perfectly Blu-ray compliant ........
RainbowThief
17th July 2020, 14:01
I don't think PAL 25i is compliant on worldwide Blu-ray players. We will need masters that can also be used for other projects which will incorporate film clips etc.
Sharc
18th July 2020, 00:00
I've experimented so far by recording to high-bitrate DVD-R and ripping with HandBrake and forcing the frame rate change from 25 to 23.976. As there's very little on-screen movement it looks pretty decent (it's a stand-up comedy show). I was wondering how I could get better results?
By leaving it interlaced 720x576 25i, anamorph. When you convert the interlaced video to 23.976fps progressive it must be deinterlaced, means one loses 50% temporal resolution and slows it down with typical audio pitch shift.
A Blu-ray player which does not play 720x576 25i should be returned to the shop IMHO as it does not comply with the standard.
You could however also bob-deinterlace the 25i video to 50p and upscale it to 1280x720 (square pixel) which is also blu-ray compliant.
I think these are the 2 options you have.
Asmodian
18th July 2020, 00:45
The original video masters to two shows have been lost, all I have are PAL VHS ex-rental tapes which I need to convert for use as extras on a Blu-ray release. The original (lost) masters were shot in the PAL format in 1982.
I use a Panasonic 1980p, TBC, and Blackmagic Intensity Shuttle to capture lossless. DVD is not a good capture format for interlaced video no matter the bitrate (4:2:0).
You could however also bob-deinterlace the 25i video to 50p and upscale it to 1280x720 (square pixel) which is also blu-ray compliant.
This is what I would do. I would not want to trust the player or display to deinterlace well, though many do, and 1280x720p50 is a great final format for PAL.
Sharc
18th July 2020, 08:56
I use a Panasonic 1980p, TBC, and Blackmagic Intensity Shuttle to capture lossless. DVD is not a good capture format for interlaced video no matter the bitrate (4:2:0).
Agree. Capturing to lossless 4:2:2 is clearly preferred provided one has the gear and skills. Capturing to high bitrate DVD/mpeg-2 is a poorer compromise which may help less experienced users to avoid issues with A/V sync, dotcrawl, aspect ratios, cabling and the like.
In any case, the subsequent encoding/compression for blu-ray should be done with compliant settings (format, buffer control etc.). I don't know whether handbrake does all this properly. There is a good chance that the disc authoring software will reencode everything once more to make the stream compliant.
Quite a few pitfalls ahead ..... ;)
manolito
18th July 2020, 15:04
I have been capturing analog TV and VHS for many years, and I disagree with some of the recommendations.
I do agree that the best way to capture is using a lossless codec and capture to 4:2:2 in interlaced mode, the container would be AVI. Audio should be captured as linear PCM.
Encoding to a different format and postprocessing should not be done during capturing. Even with a very fast computer this will reduce quality because it must all be done in real time.
You seem to assume that VHS is always interlaced. Of course the VHS technology is interlaced, but the content can well be progressive. And if it is then there is no need for deinterlacing at all.
Converting this captured file to 720p at 50 fps is overkill IMO. The horizontal resolution of VHS is below 300 lines, so even with a frame size of Half DVD (352 x 576/480) there should be no quality loss. Full DVD size is all you need, and AFAIK DVD compliant MPEG2 streams are compatible with BluRay.
scharfis_brain
18th July 2020, 16:08
Since I've not seen a TV with a better deinterlacer than QTGMC,
I also tend to upscale any VHS-content to 720p50.
MPEG2 interlaced is a horrible mess:
- fast action still is very blocky with DVD compliant 9.8 Mbps.
- interlaced YUV 4:2:0 will smear chroma even more in the vertical direction and most Bluray-players won't handle interlaced 420 chroma gracefully (CUE)
- any effort done into denoising will be lost in MPEG-2 artifacting.
- most TV sharpeners will enhance all MPEG-2 related artifacts even more.
My workflow:
- adjust luma chroma to make it fit well into 16..235 Rec.601
- crop black bars and garbage from the outermost portions of the video
- use QTGMC with some VHS related tweaks (heavy chroma processing etc.)
- apply awarpsharp to align chroma to luma (formerly known as chroma transition improvement, CTI)
- enhance textures and detail with some sharpener, without introducing bloaty oversharpening
- nnedi3 for vertical doubling
- spline36resize to 960x720
- adding left and right borders according to taste (black, blurred zoom etc.)
- encode using x264
Sharc
19th July 2020, 20:26
It seems that the OP has lost interest, or he is learning Avisynth, or we have scared him off .....:(
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