black borders and bitrate

[svdf]

hello, i was wondering about the black borders... do they actually require a high bitrate... or let's say: if i have a mpg with black borders, is it larger/smaller or the same size as one which is encoded with "full screen"

because i have a widescreen movie and a 16:9 tv, but if i encode it fullscreen and i stretch it on my tv i get a stretched out image, because i need a black border around it... so i encode with "full screen keep proportions"...

so does it take bitrate? those black borders.. and if they do: haw can i make them at least smaller so that if i stretch it on my 16:9 tv, i get the right proportions...

thanks

[DJRumpy]

Black borders require very little bitrate, for MPEG, as they do not change from keyframe to keyframe. Unfortunately, you didn't specify which type of MPEG and resolution your going for, so we can't help you. Try giving us a little more info. Is this MPEG for DVD, and at 720x480, half D1 (352x480), SVCD (480x480), etc...

[svdf]

well i'm making an (X)vcd with a resolution of: 720 X 576. i thought of useing center(custom size) but i couldn't find out what the height would have to be...

i hope you can help me now

thanks
stef

[energy80s]

Just crop the borders out and replace them with pure black in the TMPGenc crop feature. This will keep your frame size correct and allocate the maximum amount of bitrate to the actual image.

[svdf]

? you mean cut the sides of so that i have 16:9? but i don't want that... i like the borders!...no i want jus to make them smaller in the mpg so that i have less bitrate for them so there is more left for the movie... i hope you understand it... it's dificoult to explain in english

grd

[Truman]

The pure black borders have no motion and not much details / sharp edges / colors. That means, the borders will only encoded for I-frames and because there is only one color and no motion, borders require a very low bitrate.
If you want to convert 1:2.35 to 16:9(for example), the borders get smaller and the actuall movie gets bigger. So you need a higher bitrate to encode that movie.

[svdf]

If you want to convert 1:2.35 to 16:9(for example), the borders get smaller and the actuall movie gets bigger. So you need a higher bitrate to encode that movie.

yeah that's what i want... to have more bitrate for the movie so that the quality gets better...

[energy80s]

You've lost me there!

My suggestion removes the borders already coded on the disc and replaces them with pure black stripes. This will guarantee the minimum amount of bitrate will be used to re-encode them, with the vast majority of the bitrate going to the actual image.

[svdf]

ow well no maybe you didn't understand that i have an divx movie... they don't have black borders...(forgot to tell ) so what i was thinking: is there a way (frameservind in vdub or something) to add borders to the avi file so that it's 16:9 resolution (without cutting the edges off!!) and then encoding it in tmpgenc in fullscreen mode... i've tried but i don't know wich filter to use...

[DJRumpy]

To answer your question, you need to encode your 16:9 movie as a 4:3 movie. This will add letterboxing to the movie, while keeping it 'whole'. Most if not all DivX movies you find on the web are usually 16:9 with any letterboxing chopped off. Use the following to add the letterboxing back on for a 4:3 movie, just fill in the missing vertical resolution to bring your file into spec.

For example, if your DivX file is 640x272, and you want to convert it to DVD resolution, then you would convert it to 720x304, and add borders to fill out the 304 vertical to 480 (ntsc).

Same example, converting to SVCD, you would resize to 480x208, and fill out the remaining vertical (480-208=272) to 272 letterboxed area ( 272/2 = 136 top and 136 bottom letterbox)

1:2.35 movies: 720x304, 640x272, 576x240, 512x224, 480x208, 400x176

1:1.85 movies: 720x384, 640x352, 576x304, 512x272, 480x256, 400x224

1:1.33 movies: 720x544, 640x480, 576x432, 512x384, 480x368, 400x304