5.1 Dolby Surround not working on DVD burn

[JeremyAndrewDavis]

I have an Encore project for a feature film.  I built the project with the option to choose 5.1 Dolby surround or stereo. When I burn the project as a Blu Ray the disk plays the 5.1 surround properly. When I burn the same exact project as DVD the 5.1 plays as a stereo mixdown. 

How can I get the 5.1 audio to play properly on the DVD?

Thanks in advance.

[Richard M Knight]

Are you making the 5.1 file as a Dolby Digital AC3? what is the data rate.

[JeremyAndrewDavis]

Yes, the Dolby audio is AC3. I don't remember exactly the bits/sec I used to export the AC3 but I want to say 640kbps. Is there a way to look that info up after the file is created?

Thanks for the help.

[Richard M Knight]

640 is a valid data rate for Bluray but is too high for the DVD spec. Encore is probable re-encoding it in to a lower data rate stereo.

If you are using Premiere look at the mpeg2 dvd export, it will give you the highest data rate for dvd, I think it is 448 (or something similar)

[neil wilkes · Accepted solution]

640kbps is indeed too high for DVD-Video specifications, although some players will actually output this correctly. That said it is a bad idea to deliberately include a stream that will not play properly - if at all - on all systems.

Maximum data rate for AC3 on DVD-Video is indeed 448kbps, and it may interest you to know that this data rate has all the top end going unidirectional above 14.4kHz - this means you lose a lot of the pan information.

I would also avoid using AC3 on Blu-ray. Encore will accept DTS, and may even accept DTS-HD MA (I will test this) in passthrough mode (meaning you will not be able to preview the output) and to my way of thinking, AC3 is the lowest grade you can use for 5.1 on Blu-ray and I believe it should never be used. That is a personal opinion though.

[neil wilkes]

Sorry about the additional post - I hit the wrong key.

To continue from the above I strongly suspect the system has automatically downmixed the 5.1 to stereo.

Whether or not this has happened in the actual transcoding to AC3 or the downmixing has happened in the actual DVD player (highly possible because the encoded bitrate is just too high) is hard to tell - what happens if you right-click the encoded AC3 file and check it's channel count using something like MediaInfo? If you can download & install mediainfo and have a look, we can ascertain what has happened from the results page.

(After installing the tool, please open it & set the preferences to allow the right-click context menu which will then allow you to simply select the AC3 file, right click on it & have a report onscreen in seconds)

[JeremyAndrewDavis]

Thanks guys!

Dropping the data rate to 448kbps did the trick.