How to convert progressive to interlaced

[Rafael Amador]

The standard for 1920×1080 is always Interlaced. Progressive stuff is broadcasted/streamed as interlaced., so just send the movie as it is.
To make real interlaced from progressive stuff would take very long and will degrade de picture.
rafael

[Andrew Rendell]

Just putting the 1080P footage into a 1080i sequence will make it output in PSF (Progressive Segmented Frame) where the lines will be split into field one and field two. That’s how progressive is usually handled. TBH, I don’t know anyone who has bothered trying to fake the time separation between field one and field two anyway.

You can transfer from 8 bit to 10 bit… you won’t get the full benefit of the 10 bit space but most broadcasters I deliver to will accept material originated in 8 bit at the moment.

[Anette Olsen]

Rafael, what do you mean by the ‘standard’? When I do the export to Quicktime from the timeline? (I use fcpX).

I read somewhere, that if the sequence is progressive it won’t export to interlaced – but this is what you say?

(and how can I check if it is? The info doesn’t show…)

[Rafael Amador]

[Andrew Rendell] “Just putting the 1080P footage into a 1080i sequence will make it output in PSF (Progressive Segmented Frame) where the lines will be split into field one and field two. “
No need.
You will lose one generation.
If you just interpret the file as Interlaced, it will be read field by field instead of the whole frame at once.
As I said, the standard for 1920×1080 is interlaced, so whatever the file is Interlaced or progressive, it always be read/streamed field by field.
When your camera records 1080p, the SDI puts the picture out field by field this doesn’t change the Progressive nature of the picture, because both fields (upper and lower) have been generated at the same time. No between-frames motion.
Just give them the 1080p master. Their system will play it field by field.
rafael

[Andrew Rendell]

[Rafael Amador] “You will lose one generation”

What do you mean by that ?
Digital video doesn’t have generation loss unless you process the pictures in some way, e.g., transcoding to a different codec.

We’re both effectively saying don’t change it.

I’m really only adding that I’d make it into an interlaced file myself, inside the NLE, rather than giving it to the channel as a progressive file, and that’s because a couple of years ago I delivered a progressive file to a broadcaster and their playout screwed up the field order and caused a load of grief going backwards and forwards trying to apportion blame – in the end I had to hold my hands up and take responsibility because I hadn’t delivered precisely what their delivery spec was.

[Rafael Amador]

[Andrew Rendell] “What do you mean by that ?
Digital video doesn’t have generation loss unless you process the pictures in some way, e.g., transcoding to a different codec.”
Well, you wrote: “Just putting the 1080P footage into a 1080i sequence will make it output in PSF”.
In that case the sequence will be rendered and, unless your 1080P master is Uncompressed and you process Uncompressed, the movie will be recompressed. One generation lost.

[Andrew Rendell] “a couple of years ago I delivered a progressive file to a broadcaster and their playout screwed up the field order and caused a load of grief going backwards and forwards trying to apportion blame – “
if the file was Progressive, there is no way to mess up with the fields order.
it can be read as Progressive, Upper first or Lower First; Always will look progressive. Al the lines of any frame have been recorded at the same time. No motion difference between both field if read as Interlaced..
rafael

[Andrew Rendell]

[Rafael Amador] “if the file was Progressive, there is no way to mess up with the fields order.”

I think you are making the mistake of assuming that play out technology is similar to edit suite technology and that the people who operate it are similarly technically adept as editors. The first one isn’t true and the second can’t be taken for granted.

I have seen files transmitted where the fields were wrong, so for example line 566 was above line 3 instead of below it, so to imply that that’s impossible is deeply mistaken.

I learnt a long time ago to deliver precisely the specification that is requested. That’s the only way for it not to be my fault when things go awry somewhere along the line.

[Anette Olsen]

Andrew and Rafael, thanx for trying to help.

I might try Rafaels suggestion of putting my progressive sequence into a interlaced sequence – only I’m working with FCP X and it doesn’t seem to give the possibility of choosing…

So my question remains, if Compressor can be used to convert from progressive to interlaced?

[Rafael Amador]

[Anette Olsen] “I might try Rafaels suggestion of putting my progressive sequence into a interlaced sequence “
I haven’t suggested that.
Things are more simple.
rafael

[Anette Olsen]

But you wrote this: “Just putting the 1080P footage into a 1080i sequence will make it output in PSF”
what did you mean by that then?

And is that possible in FCP X?