Encoding VBR MPEG1

[SimonSez07]

I use AVISynth to create VCD resolution AVS files from my DVD's using DVD2AVI and MPEG2DEC. I then want to encode the video into Variable Bitrate MPEG1 files at the highest quality possible for playing in my SEGA Dreamcast.

I usually use CCE for my SVCD's, but when I use CCE for VBR MPEG1, I get files that are about half the size I expected. I cannot indefinately increase the 'average bitrate' setting to achieve proper filesizes because I am limited as to what I can set the 'maximum bitrate' to because of the capabilites of the Dreamcast's MPEG Decoding Engine.

When I use TMPGEnc instead, it is MUCH slower, I am unable to ensure that keyframes are inserted at scene changes, and I think the video is converted to the RGB colorspace before being encoded (which decreases overall quality).

Any ideas???

Thanks,
Simon

[cofferscuffs]

1) AVIsynth keeps the YUV format so there is no YUV->RGB conversion.

2) File size in VCD/SVCD does not relate to quality or time of the video.

3) This post was in the wrong forum - moved now.

Sorry I can't help you more.

[SimonSez07]

Originally posted by cofferscuffs
1) AVIsynth keeps the YUV format so there is no YUV->RGB conversion.

Correct, AVISynth keeps the YUV output untouched from the MPEG2 decoding process, but I think TMPGEnc converts each frame to RGB before sending it to the MPEG Encoding Engine which would then convert it back to YUV before encoding, resulting in quality loss.

Originally posted by cofferscuffs
2) File size in VCD/SVCD does not relate to quality or time of the video.

I'm not entirely sure what you meant by this, but the three attributes you mentioned (File Size, Quality, Duration) are indeed related. For a fixed Duration, the larger the File Size, the better the Quality.

Thanks for your suggestions and thanks for putting my post in the right forum.

-Simon