max video/audio bitrate for DVD

[Eric J]

I recently received my Pioneer A05 and I am experimenting with encoding before actually burning any DVDs.

I am using MyDVD as provided with the A05. MyDVD requires PCM audio, eliminating AC3 as an option.

I have been experimenting with TMPGEnc to encode, given all of the negative reports in connection with encoding with MyDVD. I recently discovered that if I load the DVD/NTSC presets under TMPGEnc, I cannot adjust the video bitrate to any higher than 8000. However, if I open a new project, do not load any presets, and set all parameters manually, I can set a video bitrate higher than 8000, at least up to 9500, which I understand is the maximum used on commercially pressed DVDs.

I understand that a combination of high bitrate video and PCM audio will have implications as to the total amount of footage I can fit on a single DVD. However, given my intended content (home video) that is not a concern.

Is there any other limitation, such as a total combined audio/video bitrate that I need to be aware of? I plan to use the burned DVDs both on a computer with a software player as well as in a set top box with a television.

Also, does anyone have experience using video bitrate settings greater than 8000 under TMPGEnc? I am considering VBR, max 9500, average 8000, and minimum 5000 or 6000. I am willing to live with long encode times and (relatively) limited total footage on a single DVD, but I would like to have the highest quality image possible.

Any insight would be greatly appreciated.

Regards,

Eric J

[SLK001]

The overall maximum bitrate for a DVD is 10.8Mbps, of which 9.8Mbps is the maximum video. The rest is allocated to ALL of your audio soundtracts (if they are present on the DVD they have to be included) and ALL of your subpicture streams. There is also a navigation stream that is about 1Mbps that goes on top of the audio and video.

There is some mis-conceptions on this board about lowering the bitrate so that there will be less pixelization. This is totally untrue - DVD data is read from a disk at a CONSTANT 11.80Mbps all the time. If you only use 5Mbps it doesn't matter, because the data is still read at 11.80Mbps. The extra 7.8Mbps is simply discarded by the player.

The maximum audio for a STANDARD audio stream is 912kbps. However, PRIVATE AUDIO STREAMS (such as DTS and SDDS) can be higher. I believe the DTS can be up to 1.56Mbps.

[Eric J]

SLK001, thanks for the detailed reply.

If I understand correctly, then, there is no implication of the requirement for PCM audio by MyDVD upon the available video bandwidth. The video stream gets allocated 9.8 Mbps without regard to the amount of audio bandwidth consumed. As such, I should be able to go hog-wild with the video bitrate (up to the stated 9.8 Mbps) as long as I am willing to live with the space constraints.

If I have misinterpreted anything, please set me straight.

Regards,

Eric J

[SLK001]

A danger of encoding at the max, is that some encoders don't "hard limit" at the maximum rate, but actually allow the bitrate to exceed the maximum rate. A lot of authoring programs will reject your video stream for max bitrate violations (they all should). Very, very, very few video clips need to be encoded at the max rate. As a guide for what value you should set your max rate, check the video stream using BitRate Viewer to examine the "Q"uantification factor. If it is under 10, then you have a very good encode at your bitrate. CCE has the ability to check the "Q" and adjust the bitrate accordingly on the fly.

For your audio (home video) you should be able to keep your audio around 128 - 192kbps or less and not notice any quality drop. The implications for your audio is that it should be less than 912kbps.

[SLK001]

Let me correct somethings that I said above:

The overall MAXIMUM BR of a DVD is 10.08Mbps.

Here are the DVD particulars:
1) RAW data is read from the disk at a constant rate of 26.16Mbps.
2) The 16/8 demodulation process reduces this to 13.08Mbps.
3) Error correction consumes 2Mbps, leaving 11.08Mbps of program/navigational data.
4) Data Search Information (DSI) consumes 1Mbps, leaving 10.08Mbps being fed to the program buffers.
5) The MAXIMUM video BR is 9.8Mbps.

[Eric J]

Thanks again, SLK001.

Regards,
Eric J