Scenarist and 16:9 mpeg-1 encodes

Rexversusu · Messages: 141 Registration: 06.21.2002

Hi all, Trying to build a dvd from vcd sources, specifically 16:9 mpeg-1 352x240 NTSC (progressive), 23.98 fps. Scenarist complains about the 16:9 aspect ratio being incorrect, as well as the 23.98 fps (yes, the asset is in it's own VTS). I know that 23.98 fps is a legal frame rate for dvd, and that 16:9 is certainly allowed. I hate to have to transcode to mpeg-2 (so i can set 3:2 pulldown), does anyone know what resolutions/formats Scenarist allows? Thanks!

arpecker · Messages: 201 Registration: 04.16.2002

Most probably your bitrate is off, as Scenarist doesn't allow more than 1858kbs on mpeg1 streams.

bmw325iman · Messages: 98 Registration: 10.29.2002

uhh, i think the dvd spec only supports 25 and 29.97 fps, and also supports 23.976 'FILM' when it is 'pulled down' to 29.97 with TFF and RFF flags? Enf...

comrade1 · Messages: 727 Registration: 07.05.2003

Bitrate is standard VCD 1150kbps, so that isn't it. Unfortunately, 16:9 issue aside, it does appear that 23.98 fps isn't supported unless 3:2 pulldown is set, which you obviously can't do on an mpeg-1 stream. So, I guess I'll have to transcode to mpeg-2 at a high VBR bitrate and set 3:2 pulldown. You know, it seems to me that there ought to be a way to convert mpeg-1 to mpeg-2, without re-encoding. After all, IIRC, the actual algorithm is the same, in terms if I, B & P frames, however mpeg-2 supports all the nifty header extensions, like 3:2 pulldown, fields, etc.

Soungazm · Messages: 251 Registration: 06.09.2003

Flood: why would you need to use a high VBR bitrate to transcode to mpeg-2? Being that the source is low bitrate I wouldn't think you would need any higher than say 3000kbps peak to maintain the same quality.

EvilM3 · Messages: 179 Registration: 10.06.2001

Because the source contains a good deal of mpeg artifacting, and re-encoding produces a good deal of quantization (i.e. mpeg doesn't deal very well with noisy source). I ended up with an average bitrate of about 3500 kbps, peaking up to 7-8 mbps during action-heavy scenes. While the re-encode is slightly lossy, it's only barely noticable. I probably could have jacked the bitrate way up, and had no noticable loss, however disc space was a concern (trying to fit four 45 minute episodes on one dvd + menus), so I opted for some loss.