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Hey!


I'm still a bit unsure about max bitrates for 3D encodes. I know that you have to add 1/3 of the target bitrate for the 2nd eye stream and I read somewhere that 38 Mbit/s must not be exceeded. Does that mean that if I have an audio stream that is 2 Mbit/s I get 36 Mbit/s, I have a maximum target bitrate of 24 Mbit/s (24 Mbit/s for the left eye / 12 Mbit/s for the right eye?)

Cheers!

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Hello Jan,

The Blu-ray Disc Association specifications state: The maximum bitrate for a 3D Blu-ray playlist is 64 Mbp/s

The max bitrate for the video streams in a 3D BD playlist is 60Mbp/s.

(The maximum bit rate for the Base stream can be no more than 40 Mbp/s)

If you are using the DSE MVC encoder, we recommend that you do NOT use the default setting of 38 Mbp/s which references the base stream bit rate. Using a lower BR such as 32 as the max for the base stream will still provide great quality and good assurance that you aren't in danger of over loading the allowable BR for the MVC streams.

All other assets in the playlist, like audio and subtitles must not exceeded 4 Mbp/s combined.

Best regards, Rob

Hello Rob,


thank you very much for the quick and informative answer!

Kind Regards,

Jan

No problem Jan,

Allow me to clarify a bit.

Since the max bit rate is 64MBPS for a 3D Play list you can have your audio streams and subtitle stream assets add up to more than 4 Mbps as long as the video streams Mbps does not cause the combined bit rate to go over 64. It is a balancing act if your playlist is crowded with assets and you are trying to use as high a bit rate for your assets. It is not uncommon for the Video Streams as an example will have to be re-encoded at a lower bit rate to allow the compiling of the 3D playlist to pass with out errors or warnings in DSA.

Rob

Hi Rob,

could you elaborate a bit on the whole issue. 

Often, with VBR 2D encodes, I am seeing very high, short spikes with encodes (over 50) but never had any issues. Neither Dostudio nor Eclipse or Sony's verifiers complained.

I sometimes get warnings (no error though) in the log with MVC encodes going over 64 though Eclipse also doesn't complain afterwards and the discs replicate and play just fine.

I have, however, never managed to get MVC encodes from Cinevision that a client supplies to pass Eclipse when used in combination with Dostudio (and the confirmed settings during the encode are very, very low - 25mbit for the base). I get the same over 64mbit warning in the log as I sometimes do with other encoders that replicate and pass just ok, however, with Do projects with Cinevision MVC encodes Ecplipse always spews out errors and I have to ask for the source files and encode again myself. I have also been told by my client that those files mux and pass just fine within Scenarist projects.

Hello Peter,

I haven't seen too many 2D VBR encodes that quickly "spike" above 50Mbps, but I can see how that may not trigger a response from the DSA mux engine or the BDROM Verifiers.

One thing to remember with Eclipse verifications done at the replicator. These reports are not meant to be full BDROM format A/V verifications. Meaning they aren't doing full compliance checking of the content of the project. The Eclipse verifier is doing replication capable verification. That is why there are other BD-ROM verifiers that should be used to fully check a BD project for compliancy before replication. The Eclipse verifier is not an approved BD-ROM verifier by the BDA.

Without knowing what other assets are in your playlists when using Cinevison encoded MVC files, it is hard to comment on why you are seeing buffer overflow errors/warnings in the DSA log or from the Eclipse reports.

Hope this helps, Rob

Hi Rob,

tnx for the reply.

I had two 5.1 DTS-HD Master audio file in my playlist, but even without any audio at all I got the error. The only thing that helped was a re-encode using a different encoder.

I had this happen on three different projects from different sources but all were Cinevision encodes so it seems unlikely to be an operator error on the original encoding side. And this was with a very low max bitrate for the base of 25mbit which is way below what should be acceptable. I am curious to hear weather anyone managed to get a Do 3D project with Cinevision MVC assets successfully muxed and replicated without issues.

Peter

Hello Peter, If you would like to share the encoded Cinevison streams that you are referencing I would be happy to run them through the Sony BD Verifier to confirm if they are BD spec compliant. I would also create a similar project and see what I can reproduce.

Send me an email at dostudiosupport@am.sony.com

best regards, Rob

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