PAL disc question...

[mjl1297]

I have a region 2 PAL disc that I would like to crop just a wee bit of the bottom due to a slight jitter in the original transfer. After I do the crop I would like to do the re-encoding preserving the original quality of the file. Size of the final file isn't a concern at the moment. What is the best way to save this DVD to my hard drive and what programs should I use to open, crop, and re-encode in order to accomplish my objective as outlined above? I was thinking DVD decrypter to get it to my HD and doing the crop and re-encode in Virtual Dub but I'm unsure of the settings to use.

[ricardouk]

1- demux dvd (audio + video) with dvd decrypter

2- crop your video track with an avs script

DirectShowSource("C:\demuxed video.m2v", audio=False)
Crop(8,2,-9,-4)
Lanczos4Resize(720, 576)

3 - convert your avs script with hcenc or quenc

4 - mux the audio track from step 1 with video output from step 3 with muxman to create the dvd structure

5 - burnnnnn

[hech54]

The only reason to use DVDDecrypter would be if you wanted to take the entire contents of the disc as one, giant VOB (File Splitting - NONE in the settings)......since I'm guessing this is a home-made DVD?

Adding a black border onto the video would be much smarter than cropping IMO. There is a cool VDub plugin called Border Control that I use often to mask overscan. Add enough border to mask the overscan then use the same amount on the other 3 sides to make it look nice....no change to the original size of the video.

[ricardouk]

Avs2DVD can do this for you in one go, you can edit the avs script it uses internally by adding crop or black borders through avisynth, in avs2dvd select the option to not reconvert the audio.

[poisondeathray]

After I do the crop I would like to do the re-encoding preserving the original quality of the file.

Not possible when you re-encode for DVD (lossy compression)

[mjl1297]

After I do the crop I would like to do the re-encoding preserving the original quality of the file.

Not possible when you re-encode for DVD (lossy compression)

Why not since it is all digital, if it is a DVD to begin with, and if I do everything without any compression?

hech54 this is a commercially produced DVD that I basically just want to duplicate and crop or black border the bit of jitter at the bottom of the widescreen image.

[poisondeathray]

After I do the crop I would like to do the re-encoding preserving the original quality of the file.

Not possible when you re-encode for DVD (lossy compression)

Why not since it is all digital, if it is a DVD to begin with, and if I do everything without any compression?

Because the transformations you are requesting require re-encoding (either a crop + resize, or overlay method) .

You could use uncompressed or lossless recompression , but that's not DVD compatible.

You will suffer at least 1 generation loss of MPEG2 compression, there is no way around it.

[guns1inger]

Don't crop and resize unless you know for sure your video is progress. If it is interlaced you will damage the image. Also, cropping and resizing distorts the image. This is why borders are being suggested.

If you use a lossless codec then you will minimise damage, however you will end up with a 60+ GB file. If you want to put this back on DVD at some point, you will have to re-encode it to mpeg-2, and will lose some quality at this time. If you use a high quality encoder and don't try to squeeze the file size too much, you may find the loss is not visible, or barely visible.

[mjl1297]

I'll go with the borders then if I do it. I'm starting to think it may be a media issue and the particular player I'm using as I am not seeing it in other players.

It is odd to me that you would suffer generational degradation with an all digital workflow even if you kept things the same format throughout and used a quality encoder. I thought the whole point of digital was to avoid the issues that were inherent in the analogue workflow.

[poisondeathray]

I'll go with the borders then if I do it. I'm starting to think it may be a media issue and the particular player I'm using as I am not seeing it in other players.

Are these different hardware players? Different displays? It could also be degree of overscan on various displays obscuring the borders

It is odd to me that you would suffer generational degradation with an all digital workflow even if you kept things the same format throughout and used a quality encoder. I thought the whole point of digital was to avoid the issues that were inherent in the analogue workflow.

Both re-compress ; but the difference with a digital workflow is there isn't additional transmission losses on top of the generational losses (e.g. due to cables , interference etc...)

The 1's and 0's are bit for bit identical when you transfer digital information . But you aren't just transferring it, you 're changing the information itself when you overlay a border or crop/resize the frame. If you stay in the digital domain as uncompressed format, there are no additional compression losses, only the 1's and 0's that you changed are modifed. But that isn't compatible with DVD-video standard. You require MPEG2 compression, and you cannot alter parts of a frame without re-encoding those affected frames (and possibly more than those frames due to long GOP compression). Each time you re-encode, more data is thrown out when using lossy compression , this leads to artifacts , rounding errors, and loss of information