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View Full Version : Buffer Underflow in Scenarist BD 5.7


iJohn
6th April 2012, 14:26
I've been trying to mux a Bluray 3D, but I keep getting a buffer underflow. I read a whole topic about it on this forum, but the whole calculation thing seems a bit vague to me.

About the (encoded) blu-ray: I used 15.5 Mbps bitrate for the base view with a maximum of 35 Mbps (default in Cinevision). For the dependent view I used a bitrate of 9.5 Mbps with a maximum of 20 Mbps (also default).

I knew that bufferflow could happen, from the guide i've been following to create this 3DBD, and how to solve it (changing the tsmuxerrate). So thats what I did, the video+audio bitrate combined should be the tsmuxerrate and this usually falls between 37-42m. But my encode resulted in a 25 mbps bitrate + DTS (1509 kbps), so I tried 27 mbps but this resulted in an underflow in about 10 seconds. When a lot of other tsmuxerrates didn't work out, I tried everything: 18-19-20-21-22-23-24-25-26-27-28-29-30-31-32-33-34-35-35.5-36-36.5-37-37.5-38-38.5-39-39.5-40-40.5-41-41.5 (here is where I am currently)

I began with halfs when the mux started to progress, from 35 on the underflow came at 50% of the mux. From tsmuxerrate 37000000 and further I started getting the underflow at 91%.

By default the Base tsmuxerrate was set on 42000244 and the dependent on 21999744 (still is).

Anyone can help me with the calculation? (buffer/maxrate)
Should I change the tsmuxerrate of the dependent view aswell?
How can I prevent this in the future? Lower the maximum bitrate in Cinevision?

mp3dom
6th April 2012, 18:03
If I'm not wrong, there are two particular PDFs in the knowledge base of Rovi that explain how to avoid buffer underflow when muxing 3D project and what are the considerations to use when you need to encode for 3D projects. Honestly I'm not working with 3D projects, so I can't help you directly.