FS7: FS7 - Outputting 25/30fps through HDMI output

J

joshbirchfilms

Member
Guys,

Today I was trying to output 25/30fps through HDMI output on the FS7 and I was having trouble. Whenever I outputted this and connected the HDMI to decimator it was saying the FS7 was outputting 59.97 rather than the desired 30fps. Is it only able to output at 50 or 59.97 fps?

Also was having the same issue with the A7sii, but from what I gather that is limited to only 60fps output through HDMI

Any help would be appreciated

Josh
 
Yes what you are seeing is correct in the case of he FS7. For example if you are shooting HD and select in your menu "Video/Output Format/" and select 1920 it will come up as 1920x1080PsF. This PsF setting stands for "Progressive Segmented Frame." This is actually a progressive output but it is constructed in such a way that the 25 frames are stored into an interlace (50i) container. Each frame is broken into two identical fields with no 50th of a second time displacement between the lines as would happen if it were a true 50i recording. The reason this system was developed was that CRT monitors were on the whole with just a few exceptions only capable of displaying 50/60i interlaced signals. By splitting and outputting the 25/30 frames into 50/60 fields the signal could be displayed on CRT monitors even though the signals were in fact progressive. External recorders, convertors etc will see this PsF signal as Interlace and this is correct because that is actually what the recorder or converter is seeing, an Interlace Container. Not to worry you are actually recording 25/30p but with each frame split into two identical fields.

Where a problem can arise with this recording method is when it comes to post production. Many NLEs will detect the incoming footage container as interlaced and say "Ah! Interlace footage" and set the project up as an interlaced project. Or the editor will if he thinks it is interlaced footage. This is obviously incorrect as we know the footage contained in the container is progressive. This is a trap for many editors who aren't aware of the progressive storage of footage in interlace PsF containers. Post production must be made aware of the fact that this is progressive footage and that that the project settings MUST be set to PROGRESSIVE regardless of the fact whether the editor or the NLE thinks the container is interlaced and therefore sets the project to interlaced. A big no, no! If the footage is treated as interlaced in the project you will end up with a lot of head scratching and heartache in post. Make sure the NLE is treating the footage as progressive and you are all set to go :)

Happy shooting

Chris Young
CYV Productions
Sydney
 
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