Film-Tech Forum ARCHIVE: Christie server buffer overflow DCP 4K

This is topic Christie server buffer overflow DCP 4K in forum Digital Cinema Forum at Film-Tech Forum ARCHIVE.

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Posted by Jordi Aguila (Member # 9875) on 04-18-2018, 12:09 PM:

Hello, we have delivered a disk with a 4K DCP OV with subtitles and another one (VF) with an insert of the title translated.One cinema with christie servers says that they can play perfectly the subtitled version but the dub. version with the insert crashes at the begining of the movie by a buffer overflow.

Do you know if it could be because I have trimmed reel one and insert the title?

Tested in Doremi server without problems.

Posted by Carsten Kurz (Member # 5396) on 04-18-2018, 04:56 PM:

One would have to look at the metadata to see what happens. From my experience, DOREMIs are quite forgiving. At the same time, subtitling using timed text is a bit critical even in standard scenarios, and I would never create a VF with subtitles for a subtitled OV. Thats calling for trouble...not everything that works on a mastering station works in the field.

- Carsten

Posted by Jordi Aguila (Member # 9875) on 04-20-2018, 07:08 AM:

Hi Carsten,

the OV DCP it's a Original Version with spanish subtitles, and the VF is the Spanish dubbed version without subtitles. All it seems that the problem is in the Christie's Buffer when the server precharge the mxfs (video and audio), because first reel is trimmed by CPL (plays first reel from frame 0 to 1'5min aprox, then it plays the litle reel of the title in spanish and then the reel 1 again just after the title). I've done this same workflow in another distribution that was delivered to all Spain without any issue, but in the another distribution was in 2K and in the case that I've now the issue is with a 4K distribution.

Posted by Carsten Kurz (Member # 5396) on 04-20-2018, 09:10 AM:

That means, the VF does not contain any subtitles at all - original subtitles stripped, and only a video insert?

Hard to say what happened there, I guess no one can, not without looking at the files and with a Christie IMS to test.

If this is still a problem, I would try with JUST stripping the subs from the OV, and then add the translated title as a timed-text subtitle. That way, the reel structure and in/out points remain unchanged. And it would work with the existing OV, you would only need to send a new VF with the sub through email.

Again, not everything that works in your mastering software works on all servers in the field. The trick is to anticipate issues and be conservative. We regularly see OVs with added features that could have been done as VFs. However, one is usually wise to NOT go this way, and instead just ignore the additional space needed on the distribution disc.

- Carsten

Posted by Ioannis Syrogiannis (Member # 3235) on 04-21-2018, 10:30 AM:

I would also go the safest way possible.
I just wonder though, seeking to entertain my curiosity: did all essences (video parts, primarily) match attributes?

Posted by Jordi Aguila (Member # 9875) on 04-21-2018, 05:27 PM:

Yesterday was the begining of the screenings and I’ve contacted with the cinemas that have Christie servers. I’ve sended a new VF via wetransfer and new KDMs for this VF and solves the issue because in this VF I’ve presserved the structure of the OV and in the title I’ve displayed a subtitle with the translation of the title in spanish, so it’s obvious that the problem is in the insert. I don’t have any other feedback about problems in the other cinemas with diferent servers. I’ve talked with a cinema that have GDC server, they have tested the DCP VF that have the problem with Christie and works perfectly. Dolby it’s the second most popular server in Spain (Doremi the first) and I supose that works too because if not we’ve had a lots of calls and we didn’t all the premmiere was ok.
Conclusion, Christie servers have problems if you trim long reels in 4K by CPL, the best option is to cut fisicaly this reel and generate new ones to aboid problems.