4:3 LB to WS

[Pentax]

Source file:
TiVo recording of a TCM movie at Best Quality (480x480, 5800), 4:3 Letterbox

Situation:
1) The file is slightly over DVD5 size (about 2%) and needs a bit of shrinkage.
2) TCM broadcasts wide screen as a postage stamp and no matter how much I manipulate the DVD player's zoom, my HDTV's many format options or the delivery to the TV as HD or SD the result is unsatisfactory; a conversion to 16:9 is needed.

Result (with 544Beta): When I create a DVD both accept non-compliant and include closed captions are checked. I use the LB to WS preset, but reset the resolution to 480x480 rather than the 352x480 that the program chose. The program sets max GOP to 15 because of the CC. And I am told that the Quality (bitrate) will be 5.71. That sounds about right for a starting value of 5.79. But at completion I am told that the bitrate is actually 4.77, an 18% reduction. I then look at the files; the VOBs total only 3.63 GB, 17% below a disc capacity. Huh?

I also created the DVD as a DL; only the GOP was changed to 15. I got a yellow triangle just after muxing started but the creation completed successfully. I ran this through DVD Rebuilder using two different encoders to shrink and convert to 16:9, leaving resolution at 480x480. The result was almost perfect; captions were lost. DVD-RB has a save captions option but it didn't work on this file. Maybe that is because 480x480 is not an officially supported resolution and I have to tweak some things to make it work.

I sure would like VRD to get the bitrate up and use all the space on the disc. Can do?

[Dan203]

Since you're doing a recode and crop anyway you should try setting the resolution to 720x480. The disc will be more compatible that way and you wont lose any quality. Plus the encoder should use up all the bits making it fit the DVD better.

Dan

[Pentax]

But why did VRD tell me it was going to encode at 5.71 and then do it at 4.66?

I tried 720x480 and came back here to report the results when I saw your reply.

The first attempt was on the same file. The result was fine, but took twice as long.

The second attempt completed as I am writing this. It did not require a reduction but it would not let me use the existing bitrate, insisting on a higher one to fill up the disc.

:)

[Dan203]

I'm not sure about that. We do use a VBR encoder so it's possible that it simply didn't need all the bits that it was given.

As for your other "issue"...

The "No Change" option maintains the original bitrate when no transcode is required. However when a transcode is require it causes the system to calculate the maximum bitrate allowed for the selected media size. This is done for two reasons...

1) We don't actually know the true bitrate of a video until it's be run through our muxer, only the header bitrate which is usually wrong.

2) When transcoding it's always best to use the highest possible bitrate to maintain the original quality.

Dan

[Pentax]

OK, I can see how the higher bitrate could provide the best chance of not lowering quality even if it can't raise quality.