JPEG2000 bandwidth setting for commercial cinema

[rtX]

What JPEG2000 bandwidth is it good/typical to select for a normal commercial cinema print? I assume the higher the better?

[rtX]

Answering my own question, having asked people who should know, I'm advised that 250 is a good setting.

[carl]

The higher the better, yes... the commercial DCPs that I have seen have varied quite wildly in bit-rate. I think the effects of J2K compression are fairly subtle, though. There is one DCP-o-matic user (an experienced cinema technician) who says that he has done A/B comparisons of conversions from Blu-Ray and could see no difference down to 50Mbits/s. Perhaps if you are using higher-quality sources you will notice more of a difference.

The bit-rate makes almost no difference to encoding time, so the only practical difference is that your files will be bigger (and hence take longer to copy / ingest).

[funkytwig]

Most commercial (holywood & Indie) use around 175. I think blu-ray equivalent is 70 no 50. It does depend on your source, if its Canon DSLR no need to go crazy.

[stereo3d]

250 are in theory, but it depends very much on your content.
If you have very grainy material all these grains will be seen as important details and require
a higher rate. However I have seen buffer overflows on dci servers especially with grain.
I would not recommend to use the highest rate.

[swirfelt]

Old thread, hoping to revive it!

Most commercial (holywood & Indie) use around 175. I think blu-ray equivalent is 70 no 50. It does depend on your source, if its Canon DSLR no need to go crazy.

I have a project shot on Canon DSLR and I am trying to produce a DCP. Because of the limitations of my computer (I assume) DCP-o-matic keeps crashing when I reach about 3% of the process when I try to use the pre-chosen bandwidth of 100.

I managed to create a DCP by lowering the bandwidth to 50. Before I try it at my local cinema I might try to run one at 75.

If the source material is shot on Canon DSLR, what would be a good bandwidth? No need to go crazy? Is 50 fine?

The Quicktime inspector tells me the source material is all below 50 Mbit/sec but that is in its native h.264 state.

Related to this is another question. My material has been edited in Premier and the DCP I just made was made by exporting as ProRes 422. Is there a point in doing this or would I be better off running an uncompressed H.264 file to convert in DCP-o-matic?

Sorry for all the newbie questions. I hope you have patience with me.

[carl]

I have a project shot on Canon DSLR and I am trying to produce a DCP. Because of the limitations of my computer (I assume) DCP-o-matic keeps crashing when I reach about 3% of the process when I try to use the pre-chosen bandwidth of 100.

This shouldn't happen... unless you are by chance running 32-bit Windows with a fast CPU. If you give us more details of this crash I can try to fix it. First questions would be: what version of DCP-o-matic and what happens when it crashes?

[Carsten]

As a general rule, 200MBit/s is a set-and-forget-setting. Some servers have trouble with rates reaching 250MBit/s, so, keep it below the max spec setting for standard content. Set DOM to 200MBit default in prefs, and then never bother again, unless you are doing HFR at some point.


As Carl points out, you may have your thread setting too high on a 32bit system/DOM software version. Try encoding the DCP with a thread setting of 4 for now and see if that makes a difference. Or switch to 64Bit system and DOM.

- Carsten

[cloud06]

As a general rule, 200MBit/s is a set-and-forget-setting. Some servers have trouble with rates reaching 250MBit/s, so, keep it below the max spec setting for standard content. Set DOM to 200MBit default in prefs, and then never bother again, unless you are doing HFR at some point.

I can confirm this. Sometimes going over 200 mbit/s can produce random green frames on some servers.

[swirfelt]

Hello,

Thank you for your replies!

So, I tried creating a DCP on my mum's MacBook Pro which is a couple of years younger than mine and has quad-core. I had the same result, the program crashed when I tried the 100mbit/s but it went a bit further before the crash, probably got to about 60% or so. Managed to get it to do one at 80mbit/s.

My set-up is as follows:

Latest version of DCP-o-matic, downloaded last week.

System Version: OS X 10.11.6 (15G31)

Model Name: MacBook Pro 15 inch (mid 2009)
Model Identifier: MacBookPro5,3
Processor Name: Intel Core 2 Duo
Processor Speed: 2.8 GHz
Number of Processors: 1
Total Number of Cores: 2
L2 Cache: 6 MB
Memory: 8 GB
Bus Speed: 1.07 GHz