Options for Very Low Complexity/Quality Video?

[SMurf]

Hello,

Here's the situation: I have a load of videos that I've viewed quite often, I know them very well. I want to be able to take them on the road, but I don't have much storage to hand (about 8 GB).

Because I know these videos, I would like to compress them in such a way as to exploit the latent images as I remember them, so I would only encode smaller, greyscale frames for example. I have no plans to do much with any audio tracks, aside from reduce to mono.

Has anyone done any research into "discernable" low bitrate, low complexity video compression (walking the tightrope between something that can be made out and meaningless blocks of goo)? By "low complexity", I mean would not cook a sub-1 GHz CPU during playback.

Are there any codecs that are optimised for greyscale input?

[pieter3d]

Hello,

Here's the situation: I have a load of videos that I've viewed quite often, I know them very well. I want to be able to take them on the road, but I don't have much storage to hand (about 8 GB).

Because I know these videos, I would like to compress them in such a way as to exploit the latent images as I remember them, so I would only encode smaller, greyscale frames for example. I have no plans to do much with any audio tracks, aside from reduce to mono.

Has anyone done any research into "discernable" low bitrate, low complexity video compression (walking the tightrope between something that can be made out and meaningless blocks of goo)? By "low complexity", I mean would not cook a sub-1 GHz CPU during playback.

Are there any codecs that are optimised for greyscale input?

Pretty curious as to what kind of content this is :)

Anyway, you can configure AVC/H.264 to suit your needs pretty easily - it even supports mono, though color shouldn't really take up much more. Just go for high QP values / low bitrate and downscale the resolution....

[raffriff42]

profile=baseline
tune=fastdecode
crf=26 - no higher unless desperate IMHO
resolution=120p, or as small as possible - preferable to cut size than quality for VLBR's IMHO
framerate=1fps, no frame-blending tricks - looks relatively good at VLBR's, but obviously not good for ping-pong matches etc :)
audio 96kbps - again, no lower unless desperate

A 480p, 30fps test video was cut in size by 90% by changing only size and framerate. But you will have to test for yourself...

[sneaker_ger]

You can probably fit many minutes of film into 8 GByte much better than 1 fps grayscale (though x264 should compress grayscale quite well since the colors are stored in separate planes that can be compressed to nearly zero). So in contrast to raffriff's suggestion I'd also try very high settings (though maybe with lower resolution):
x264.exe input --preset veryslow --bitrate XXXX --pass 1
x264.exe input --preset veryslow --bitrate XXXX --pass 2
(add --level and perhaps --vbv-maxrate/--vbv-bufsize according to playback hardware limitation)

You just have to calculate the bitrate according to the length of films/the remaining amount of storage you have.