Can I eincrease bitrate when encoding 16:9

[scottb721]

Because very little bitrate is allocated to the black bars of widescreen encodes, I assume I can increase the average VBR bitrate to make better use of disc space.


Anyone know what sort of % factor increase I should use for 1.8 and 2.3:1 DVD's being encoded to SVCD ?

I use the bitrate calculator in TMPGE wizard.

On a side note, I've noticed movies with lots of night time scenes have much smaller file size than predicted, for the same reasons as the black bar thing obviously.

[mysticgohan17]

im not sure if DVD players support 16:9 playback of svcds (im not sure if they will resize the picture to the correct aspect ratio)

[scottb721]

My SVCDs are 4:3.
They have black bars top and bottom to maintain the original aspect ratio of the 16:9 DVD.

[Dragonsf]

This has be discussed before.Standalones can't playback anamorphic SVCDs-You have either to switch your TV to 16:9 or use a resize filter before encoding.

[mats.hogberg]

I think you've reasoned one step too far. If you add black borders, the intelligent encoder will allocate very few bits to this area of the image, and use most of the avialable bitrate to where the action really is. This is out of your control, and entirely up to the encoder.
If you tell the encoder to use 2200 kbps (CBR or VBR average), it will be encoded to this bitrate (hence size), even if the effective picture area (not the black bars) is just 10 by 10 pixels. If the encoder is worth anything, it will use the bits where it's needed - the image, not the black bars.

/Mats

[Dragonsf]

My SVCD is 4:3.
It has the black bars top and bottom to maintain the original aspect ratio of the 16:9 DVD.

In that case, make sure, your borders are true black (or at leat all the pixels have the same color).

[scottb721]

In that case, make sure, your borders are true black (or at leat all the pixels have the same color).

Tmpge does the black bars during the encoding.

[proxyx99]

Its not significant (just like plain color screen). Lowest bitrate permitted under the standard. You save on motion if encoding VBR. Do the test. it may be worthwhile if you plan to do more like those. My guess would be 10-15 %.

[scottb721]

Mats - cheers mate.
So therefore, a fullscreen 4:3 won't look as good as a 4:3 with bars that uses the same bitrate as the fullscreen ?

[proxyx99]

yes, by a margin. keep in mind that since you are encoding fullscreen you use bits to tell the decoder "leave it black". Since this is encoded anyway it will use lowest bitrate for this section. Test full black against it and you will have an idea how much did the rest (motion) cost you.
SVCD has a limit max and min. Motion would be closer to max. Run any SVCD through Bitrate viewer and you will see in real time how motion affects the bitrate/size.

[mats.hogberg]

Mats - cheers mate.
So therefore, a fullscreen 4:3 won't look as good as a 4:3 with bars that uses the same bitrate as the fullscreen ?

Yes, that's right. In the first case, we have 480*480=230400 (NTSC) pixels that in theory could (and will) change between frames. Add 20 px black bars top and bottom, and the "moving" area becomes 480*440=211200 pixels. Almost all bits will go into this area, not the black bars, so bits/pixel effectively increases.

/Mats

[ronnylov]

MPEG encoding is done in blocks and macroblocks so for optimal use of the bitrate make sure that the black bars are macroblock optimized (one macroblock is 16x16 pixels).

Also you can take advantage of the overscan area of the TV even if it's a fullscreen SVCD. You can't see the outer edges of the picture so you can make them black as well.

FitCD is a great tool to calculate a macroblock optimized rezising script for avisynth. As an example I can have 16 pixels of black around the picture area of a SVCD and I can't see it on my TV because it's hidden in TV overscan area. If your movie is widesceen then you can save some bits by having 16 pixels of black on left and right side and a multiple of 16 pixels black bars on bottom and top of the picture.