want to encode VCD to h.264

[se4923]

Q1.is it possible to encode VCD to h.264 to make the file size smaller but still have the same quality (or just a little bit lower)?
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I found somewhere on the internet

"Video Bitrate could be lowered by 5%-30% compared to a regular MPEG-4/DivX/XviD without
any quality loss."

so I think it possible for VCD(MPEG-1) too but I don't know which Bitrate I have to use

=========================
I see the chart from this file
http://postgrad.eee.bham.ac.uk/gxd186/VideoCoding.ppt
and see that

at the same psnr
mpeg1 use 1000 kbps ,h.264 use 400 kbps = lower 60%

so VCD use 1150 kbps I encode h.264 with 460 kbps

Video size and frame rate are the same as original

but I got the poor quality

===========================
Q2.I want to ask which Bitrate I should use OR should I try muliplepass?

thanks
(please try to understand my poor english)

[wyti]

if you want a target bitrate you should use multipass it's by far better than one pass ABR.

But if you don't care about reaching an exact file size, you sould try crf mode, crf try to maintain a certain level of quality regardless of the bitrate it use

generally : if you want to reach a certain quality level, use crf mode.
If need to reach a certain file size use 2 pass bitrate mode.

[se4923]

1.I have try crf mode and the output file size is much bigger.
2.I don't know the file size(or bitrate ) that I want but I just want it lower without any quality loss

[Ranguvar]

1.) Then use a higher CRF value.
2.) Use a bitrate calculator, like the one in MeGUI. But if you get CRF working, that should be better, as all is done in one pass.

[Sharktooth]

remember CRF 18 is a nice starting point since for most people it looks "transparent" (that means you cant distinguish the original from the encode).
keep rising it until you get your desired quality and an acceptable filesize.

[wyti]

Or if you want smaller file with the same quality you can raise your settings to more time consuming but better quality wise settings.

[Sagekilla]

VCD is typically very low resolution --- 352x240 IIRC. So you can easily get away with using some very slow settings (--subme 7 --trellis 2 --me umh etc)

[em500]

I found somewhere on the internet

"Video Bitrate could be lowered by 5%-30% compared to a regular MPEG-4/DivX/XviD without
any quality loss."

so I think it possible for VCD(MPEG-1) too but I don't know which Bitrate I have to use

=========================
I see the chart from this file
http://postgrad.eee.bham.ac.uk/gxd186/VideoCoding.ppt
and see that

at the same psnr
mpeg1 use 1000 kbps ,h.264 use 400 kbps = lower 60%

so VCD use 1150 kbps I encode h.264 with 460 kbps

Video size and frame rate are the same as original

but I got the poor quality

You might get comparable quality with much lower bitrates from h.264 compared to VCD MPEG1 if both were encoded from the same source. But if you transcode a VCD source to h.264 the situation is probably very different, and you may not save much if you want to maintain roughly the same quality as the VCD.