An interesting VEGAS 8 render problem

[compusic]

we know that a encoder based on MPEG compressing technology requires that video frame's pixel number should be integer times of 16. For example a 480X272 video frame, both 480 and 272 are integer times of 16.

for vegas 7 and previous version, for a 480X270 project ( a 16:9 project), if I want to render the video using mp4 or 264 encoder, even I set the frame to 480X270 in the encoder's setting tab, the encoder will change the frame to 480X272. I thought I knew why, since it's a MPEG encoder.

but waite, now the same project in VEGAS 8, render using mp4 or 264 encoder, if I set the output frame to 480X270 in the encoder, the encoder will not change it. the rendered video is definitely 480X270! I have cheked it using Gspot.

then why? how can this happen? does VEGAS 8 have another advanced encoder? or the MPEG compressing standard has changed or improved?


thanks.

[Dark Shikari]

It doesn't actually have to be mod16. Encoders will happily pad the edges with mirrored lines of pixels, which will be cropped automatically on playback.

[compusic]

It doesn't actually have to be mod16. Encoders will happily pad the edges with mirrored lines of pixels, which will be cropped automatically on playback.

But the encoder in Vegas 7 and previous versions does add 2black lines, change a 480X270 frame to 480X272, which has been confirmed in Gspot.

the encoder in Vegas 8 does not add any extra lines, if your project setting and ender setting are 480X270, then the rendered file is 480X270.

[desta]

It's likely that Vegas 7's encoder could actually encode @ 480x270, but that Vegas 7 itself didn't recognise it as a valid input resolution, and therefore literally added (not padded) the extra lines.

Vegas 8 has probably been updated to accept these inputs and let the encoder just pad the resolution. Like DS said, these extra lines will actually be present in the stream, but the stream info will also tell decoders to crop them off again when played back (rendered).