DCP VF ATMOS help
Posted: Thu Feb 22, 2024 4:10 pm
Hi fellow o-matics,
Long time reader, first time poster. I was mastering a DCP for a client using DOM (2.16.75, MAC book pro M1 Max), they wanted a 5.1 version to be used for most screenings but also requested an ATMOS version of the film for the odd occasions that the film will be shown at an ATMOS compatible cinema. As the main version of the DCP would be the 5.1 version it made sense to me to make the OV as a 5.1 and make the ATMOS as a VF these are the steps I took. I imported the front logos as a j2c (reel 1) and the main film as a j2c sequence (reel 2) I imported the 5.1 mix and started that at reel 2. I made the OV with 16 channels of audio. I then made a VF to add subtitles by using the 'use this dcp's...' tick box for audio and video. Then I wanted to create the ATMOS VF, I started a new project and imported the OV DCP in and also imported in the ATMOS MXF I received from the sound studio, when importing into DOM it recognised the ATMOS as ATMOS by the (ATMOS) next to the import file. I used the tick box for 'Use this DCP's video as OV and make VF' and left the audio tick box unticked. I started the ATMOS off at Reel 2 as the first frame of audio matched the video not including the reel, I checked this was correct by using the timeline view and the ATMOS tracked looked to start at the correct place, start of reel 2. The sound studio also supplied the ATMOS mxf with about 1' handles at the end so I went to the last frame of the DCP and used the 'Trim from current position to end'. Today we QC'd the DCP in a dolby ATMOS cinema. The 5.1 OV with VF with subtitles was fine and lovely, happy client. Then we came to spot check the ATMOS and the ATMOS was out of sync, the reel at the start was silent and then the audio came in abruptly out of sync on first frame of picture. Luckily the version that will be used first is the 5.1 but i need to get a working ATMOS VF1 for the future. My first thought was that I had trimmed the start of the ATMOS rather than the end, however I then realised it was not out of sync by 1' more like around 10". I then started to think that the ATMOS is some how playing from the start of the DCP including reel 1 and then jumping in when it hits reel 2. Has anyone come across this issue? Further research also suggest that I should use the 5.1 as a sync for the ATMOS, does anyone know if that is true and what that would involve? I also thought maybe I need to put some audio on reel 1 and not let DOM generate silence, if that is the case can it be 5.1 instead of ATMOS? Then my last question is how is everyone checking back there ATMOS DCPs, if I could check it back at the studio rather than renting an ATMOS cinema, even just to check that it is playing in sync, not a full check for quality, just a sync check that would save some money. I know this is a bit of a long one, any recommendations or suggestions are very much welcome. Cheers!
Long time reader, first time poster. I was mastering a DCP for a client using DOM (2.16.75, MAC book pro M1 Max), they wanted a 5.1 version to be used for most screenings but also requested an ATMOS version of the film for the odd occasions that the film will be shown at an ATMOS compatible cinema. As the main version of the DCP would be the 5.1 version it made sense to me to make the OV as a 5.1 and make the ATMOS as a VF these are the steps I took. I imported the front logos as a j2c (reel 1) and the main film as a j2c sequence (reel 2) I imported the 5.1 mix and started that at reel 2. I made the OV with 16 channels of audio. I then made a VF to add subtitles by using the 'use this dcp's...' tick box for audio and video. Then I wanted to create the ATMOS VF, I started a new project and imported the OV DCP in and also imported in the ATMOS MXF I received from the sound studio, when importing into DOM it recognised the ATMOS as ATMOS by the (ATMOS) next to the import file. I used the tick box for 'Use this DCP's video as OV and make VF' and left the audio tick box unticked. I started the ATMOS off at Reel 2 as the first frame of audio matched the video not including the reel, I checked this was correct by using the timeline view and the ATMOS tracked looked to start at the correct place, start of reel 2. The sound studio also supplied the ATMOS mxf with about 1' handles at the end so I went to the last frame of the DCP and used the 'Trim from current position to end'. Today we QC'd the DCP in a dolby ATMOS cinema. The 5.1 OV with VF with subtitles was fine and lovely, happy client. Then we came to spot check the ATMOS and the ATMOS was out of sync, the reel at the start was silent and then the audio came in abruptly out of sync on first frame of picture. Luckily the version that will be used first is the 5.1 but i need to get a working ATMOS VF1 for the future. My first thought was that I had trimmed the start of the ATMOS rather than the end, however I then realised it was not out of sync by 1' more like around 10". I then started to think that the ATMOS is some how playing from the start of the DCP including reel 1 and then jumping in when it hits reel 2. Has anyone come across this issue? Further research also suggest that I should use the 5.1 as a sync for the ATMOS, does anyone know if that is true and what that would involve? I also thought maybe I need to put some audio on reel 1 and not let DOM generate silence, if that is the case can it be 5.1 instead of ATMOS? Then my last question is how is everyone checking back there ATMOS DCPs, if I could check it back at the studio rather than renting an ATMOS cinema, even just to check that it is playing in sync, not a full check for quality, just a sync check that would save some money. I know this is a bit of a long one, any recommendations or suggestions are very much welcome. Cheers!