Hi, I have a SMPTE dcp 25fps. Can I create an Interop dcp from this with frame rate at 24fps and and add in new audio that has been stretched and pitch shifted to match new frame rate?
Seeking to provide an interop dcp in situations where spmte won't work. (without having to deliver two separate dcps)
Cheers
David
VF DVP with different frame rate and audio
-
Carsten
- Posts: 2804
- Joined: Tue Apr 15, 2014 9:11 pm
- Location: Germany
Re: VF DVP with different frame rate and audio
You can convert it to a 24fps Interop DCP, but not as a VF. It needs to be a self contained OV. You don't need to stretch the audio externally, DCP-o-matic will do it automatically when you set the new DCP framerate.
DCP image and wrapping parameters are not allowed to vary between OV and VF. A VF to a SMPTE OV needs to be SMPTE, and IOP_VF to IOP_OV.
Note it is okay to deliver 25fps in IOP. For 24/25 fps alternative versions, you need to supply separate self contained OV versions.
One type of server, the Dolby DSS/DSP100, will not play 25fps, not in IOP, not in SMPTE. For those locations, a 24fps version is mandatory.
- Carsten
DCP image and wrapping parameters are not allowed to vary between OV and VF. A VF to a SMPTE OV needs to be SMPTE, and IOP_VF to IOP_OV.
Note it is okay to deliver 25fps in IOP. For 24/25 fps alternative versions, you need to supply separate self contained OV versions.
One type of server, the Dolby DSS/DSP100, will not play 25fps, not in IOP, not in SMPTE. For those locations, a 24fps version is mandatory.
- Carsten
-
Bandersd
- Posts: 2
- Joined: Mon Jul 24, 2017 7:02 am
Re: VF DVP with different frame rate and audio
Thanks Carsten,
DCP-o-matic internal audio time stretch will have a pitch shift, will it not?
Glad to hear IOP will play 25fps - seem to get different thoughts on that.
So for best practice - to cover all bases - I should have a SMPTE 25fps DCP and have 2 alternate versions: IOP 25fps and IOP 24fps for servers that have different limitations?
- DAvid
DCP-o-matic internal audio time stretch will have a pitch shift, will it not?
Glad to hear IOP will play 25fps - seem to get different thoughts on that.
So for best practice - to cover all bases - I should have a SMPTE 25fps DCP and have 2 alternate versions: IOP 25fps and IOP 24fps for servers that have different limitations?
- DAvid
-
Carsten
- Posts: 2804
- Joined: Tue Apr 15, 2014 9:11 pm
- Location: Germany
Re: VF DVP with different frame rate and audio
Hi, yes, there is a slight pitch shift when using the automatic correction in DCP-o-matic. Did you try it in order to find out if it matters? It should only matter in those few locations running a DSS100 anyway (or a GDC SX2001, which shows some 25fps weakness as well). In many locations, these very old servers have been replaced because of this 25fps weaknesses.
At least keep in mind that many pitch shift techniques do introduce harmonic artifacts as well, and wether these or the pitch shift is more noticeable can be debated on (and is content dependent). But, of course, you can do your own tests.
IOP in 25fps have been distributed wide often in europe and e.g. australia. While it is not formally covered, all server manufacturers had to implement it practically. Some sites may have failed with 25fps and blamed 25fps INTEROP, while in fact, it was a DSS100, and a SMPTE 25fps version would have failed just as well. It is still advisable to include a 24fps version if possible, but add a note that the 25fps version is the preferred one.
- Carsten
At least keep in mind that many pitch shift techniques do introduce harmonic artifacts as well, and wether these or the pitch shift is more noticeable can be debated on (and is content dependent). But, of course, you can do your own tests.
IOP in 25fps have been distributed wide often in europe and e.g. australia. While it is not formally covered, all server manufacturers had to implement it practically. Some sites may have failed with 25fps and blamed 25fps INTEROP, while in fact, it was a DSS100, and a SMPTE 25fps version would have failed just as well. It is still advisable to include a 24fps version if possible, but add a note that the 25fps version is the preferred one.
- Carsten