DoReMi IMS-1000 - MPEG2 MXF interop

[Rowanmac]

Hi DCP'ers!

So i've got one of these DoReMi IMS-1000's...
http://www.doremilabs.com/products/cine ... ia-server/

And DCP-o-matic is a great tool, like the best tool ever actually for our baby cinema, and I've never had a problem with ingesting the DCP's it creates. But, I was wondering about the amount of time it takes me to convert content and encode JPEG2000, if there was another speedier alternative to JPEG2000.

My IMS-1000 can supposedly
■Support MPEG2 MXF interop (DCP)

Mostly, it's short crappy 16MB MP4's i'll get given to play from sponsors, I know the quality is going to be pathetic, but it blows out to an hour to convert and ends up being 23gb! We do sessions with DVD's too, but to deinterlace and convert a 1:30:00 documentary takes longer that I have the disc in my hands for sometimes. We avoid using the DVD player through the HDMI input on the IMS-1000 because the HDMI input has been glitchy sometimes and has crashed the "security manager" (so the suppliers tells me), and spewed white-noise or dropped audio entirely on occasion, forcing a reboot and fast forward in front of the audience.

I know that MPEG-2 is depreciated in DCI DCP's, but my player can still play it apparently. Does DCP-o-matic support MPEG2 MXF? I pretty sure ffmpeg could. I assume it would still be a transcode rather than a repackage, since the colourspace conversion would still need to take place? That might mean there is no time really saved?


It lists seperatly from DCP that...
MPEG2/H264/VC1
■720p, 1080i and 1080p support, up to 60fps
■Bitrates up 50MBits/s
■4:2:0 8bits

So, I can't get it to see any .mpg files (I just thought it might look for .ts files, will try shortly). I contact DoReMi, and apparently you need another multi-thousand dollar StreamIt or LE100 device to make the above work, but was wondering is anyone had any luck streaming to the IMS from a PC? Apparently it should work with MPEG-2 transport streams, but getting them there is a mystery.


Cheers,
Rowan

[carl]

DCP-o-matic does not support MPEG2 MXF interop DCPs, at present; I have thought about implementing it (for reasons of encoding speed) but so far I have been put off by the potentially large amount of work, and the fact that I would guess that support for MPEG2 MXF will be dropped from projection systems a lot sooner than JPEG2000 MXF. Hence it seems to make more sense to work on the more modern standard, and find ways of encoding that more quickly.

I'm pretty certain the encoding speed of MPEG2 MXF would be much faster than JPEG2000, probably faster than realtime on modern hardware.

If there was a lot of interest and/or financial support the priority of MPEG2 support may increase, but right now it is fairly low priority.
Best, Carl

[Rowanmac]

Hey Carl,

Would be interesting to survey the lay of the land on MPEG-2 IOP supporting players. Nevermind though, just thought it might be a simple -vcodec MPEG2 switch for ffmpeg, but like you say time is hard come by.

Thanks again for the great software.

Cheers,
Rowan

[carl]

Nevermind though, just thought it might be a simple -vcodec MPEG2 switch for ffmpeg

It might be pretty close to that ... hard to say. If there's interest, it's probably worth a look Like you say, it would be interesting to know how many MPEG-supporting projectors there are in the field and how long they might stay in the field...

[Rowanmac]

Hey Carl,

Just a followup, i've done some research and found the following DCI compliant hardware that supports MPEG-2, all the latest products seem to do it.

• Christie IMB (can apparently play generic MPEG2/4 files anyway, what a sensible idea!)
  MikroM MVC201 4K IMB
  Qube XI 4K IMB
  Dobly Show Player DSP100
  Dobly Screen Server DSS200 (latest product)
  Doremi IMS-1000
  Doremi DCP-2000
  GDC SX-3000 and SX-2000 (supports MPEG-2 though didn't specify MXF)
  Sony Server IMB-SA
  Ultra-Stereo Labs Integrated Media Block: CMS-1200 and CMS-2200

Digicine FilmStore Player - TBC, i've contacted them.
NEC IMB/IMS is unknown, struggled to find any info or manuals

Cheers,
Rowan

[Carsten]

As far as I know, Sony LMT200 and LMT300 (SRX-R220/320) are the only projection systems without MPEG-2 support.


Most servers still support MPEG-2 not only because of legacy Interop MPEG-2 releases (there have been no such releases during the last 3-4 years), but in order to support live streaming DVB-S broadcasts (live concerts, opera, sports, etc.).

Still, I think Carls time is better employed towards GPU J2k options than towards MPEG-2 support. For those servers still supporting MPEG-2, there are very different constraints with regard to allowed datarates, framerates, audio channels, subtitle support, etc.


With the industry struggling hard to go SMPTE only DCP releases, it's just not a useful ideal to now implement an even older interop variant just to have some increase in encoding speed.

Encoding can be sped up easily by investing a few hundred euros or $ into a faster or second, third, etc. CPU. It's not that everyone has to stick with 1fps or so.

- Carsten

[Rowanmac]

Hey Carsten,

I'm not really interested in distributing DCP features in MPEG-2 MXF, i'm just after a fast conversion option for local promo & advert type material in-house, that doesn't convert a 16mb mp4 into a 25gb JP2K DCP.

As far as bitrate, framerate, audio channels etc. we already have controls for those.

The thing is (for me anyway) the Doremi IMS-1000 we have highlights a "Key Feature" of "Supports MPEG-2/h264...".
But, only after you purchase and want to stream, you are told by a sales rep that you need a multi-thousand dollar Doremi StreamIt box.

I wrote the start of a program to emulate a StreamIt box. I've had the IMS-1000 connect to me on port 4242 UDP, though it's not an open protocol it seems, the server opens the port and expects a secret handshake, without knowing what the secret handshake is - it's not going to work. It closes the port after 10 seconds of no reply.

Bastards could have used a standard protocol like RTSP, but no of course, there is no money in that...

Cheers,
Rowan

[Carsten]

I know the IMS1000 has some HDMI issues, but I think it's better to use a cheap external media player - that way, no transcoding is necessary at all, for all possible applications, like DVB-S/TS, MKV, etc.

If you have some programming experience, I guess something like a WDTV, Popcorn etc. could be remote-controlled as well, and offers a much broader codec support, also with regard to audio codecs. Maybe some of these boxes offer a higher degree of compatibility with the IMS1000 HDMI port than others?


I'm concerned that to support MPEG-2, even with FFMPEG, it's not just a matter of another checkbox in the GUI. And it's not that coding time drops to zero with it. J2k for DCI is precisely defined and constrained within OpenJPEG. There is no precise codestream definition for MPEG-2 Interop as far as supported servers go. So, finding 'compatible' stream parameters will be a moving target.

- Carsten

[Rowanmac]

I know the IMS1000 has some HDMI issues, but I think it's better to use a cheap external media player - that way, no transcoding is necessary at all, for all possible applications, like DVB-S/TS, MKV, etc.

Thanks Carsten,
Yes this is probably what we will do

I too would rather see GPU JP2k encoding before MPEG-2. If I had the time, i'd try adding to the code myself. Maybe oneday

Great work here guys with DCP-o-matic!!!

Cheers,
Rowan

[df1paw]

I'm concerned that to support MPEG-2, even with FFMPEG, it's not just a matter of another checkbox in the GUI. And it's not that coding time drops to zero with it. J2k for DCI is precisely defined and constrained within OpenJPEG. There is no precise codestream definition for MPEG-2 Interop as far as supported servers go. So, finding 'compatible' stream parameters will be a moving target.

Hi Carsten et al.
I sometimes do the MPEG DCP stuff here for special shows like school screenings etc. and it works faster than realtime on my old dual-core laptop. I've created a bash script which works reasonably well at least for me. Here's the most important part of it (for clarity I snipped the 24p conversion part) - at least for Doremi 2K4 it works this way:

Code: Select all

ffmpeg -i INPUT.WHATEVER -r 24 -vcodec mpeg2video -pix_fmt yuv420p -s 1920x1080 -aspect "16:9" -b 40000k -intra -an video-out.m2v
ffmpeg -y -i INPUT.WHATEVER -acodec pcm_s24le -ar 48000 audio.wav
sox audio.wav left.wav remix 1
sox audio.wav right.wav remix 2
sox audio.wav center.wav remix 3
sox audio.wav lfe.wav remix 4
sox audio.wav surrleft.wav remix 5
sox audio.wav surrright.wav remix 6
asdcp-test -v -L -c "$(uuidgen -r).m2v.mxf" video-out.m2v
asdcp-test -c "$(uuidgen -r).pcm.mxf" left.wav right.wav center.wav lfe.wav surleft.wav surright.wav 

Then you will have two mxf files which could be packaged with OpenDCP's GUI...

If you are willing to test it on other servers I'll post a short MPEG DCP for testing purpose - or clean up code and release the bash script into public domain


Regards,
Andreas Weller