Any advantage to shooting 720 for downscale?

R

robcollins

Active member
I'm shooting a training piece that will end up being scaled to 512 x 384 (part of an interactive flash module). Is there any advantage to shooting 720 vs. 1080 for this?

Thanks in advance for any advice.

Rob
 
I have always scaled my HD footage down in post. Maybe some folks will disagree for some reason. I would rather just keep my source clips as high of a resolution as possible. Maybe you will want a higher resolution later on. If this footage is for a client and you are able to use the footage for a portfolio, you get the 1080p version, or maybe your client will want to go back and pay you for a higher resolution version of the video.
 
If it were me, I'd shoot at 1080p as well. That way, if I ever needed it higher rez like blackcat says, I have it. I've not compared 720p to 1080->720p on my AF100, but on other cameras, I've not always been impressed with the downsampling algorithms or other shortcuts they have used to reduce the resolution.
 
My thought as well, thanks for the confirmation. I wanted to make sure there wasn't something in this codec that changed the equation somehow. It begs the question, though, aside from 60p, why would one ever shoot 720 on this camera? On my EX1 it was for overcranking, but that's not an issue here.
 
I can't think of a reason why I would use it. Camera users like options, and a camera at this price point has a range of different users.

Someone might test out 720p and find out that the camera's downrez looks fine to them. I guess it could save some stress on your editing machine, but the final delivery is eventually going to be compressed in some form anyways. I would still prefer my source clips to be as high rez as possible. If I shot a film, I might only make a DVD release of it. However, I could use 1080p stills for web promotion. The stress I save on my system by working in 720p HD over 1080p is not worth it.
 
I've used 720p on the AF100 for times when the broadcast infrastructure we were using was 720p -- mainly for FlightLine Films. What we do there requires live footage and we despise interlaced, so that means 720/60p.

Outside of that environment, I always use 1080p.
 
The only reason I have ever heard is super fast turn around requirements, other than that, 1080p all the way :)
 
One positive as on all HD cameras, if you know you are going to SD resolutions 720p24 or 720p30 will give the codec more bitrate per frame as there is less information to process. So overall less compression.
 
Bassman2003 said:
One positive as on all HD cameras, if you know you are going to SD resolutions 720p24 or 720p30 will give the codec more bitrate per frame as there is less information to process. So overall less compression.
Click to expand...

If that's the case, and the difference is noticeable in theory, then that would be a good reason to shoot 720/30 in my situation. Can anyone confirm that 720 brings less compression in a way that's discernible? In the end I'm compressing the hell out of the video to FLV low bit rate (painful), so the advantage of having a 1080 master may outweigh a small capture compression edge.

Thanks all for the info and feedback.
 
Bassman2003 said:
One positive as on all HD cameras, if you know you are going to SD resolutions 720p24 or 720p30 will give the codec more bitrate per frame as there is less information to process. So overall less compression.
Click to expand...

I suppose, but you will also downrez the larger frame in post. It is hard for me to imagine a noticeable difference there, at least in a real world scenario.

I have used 1080p masters for low bit rate FLVs on several cameras. The results always worked out well for me.
 
I agree, this is where theory and practice need to come together. If there is concern about codecs, then 720p would help. I don't know if there is a concern about AVCDH at this point. People seems to be quite impressed. I have only heard noise about banding of which I do not know if bitrate would affect either way.
 
For sure, it is an interesting thought. I am having a great experience with the newer high bitrate AVCHD. I can't imagine that the 720p downrez is going to give any real quality over the 1080p downrez. Any banding would come from the camera being 8bit. Sadly, 720p can't change that. It is what it is.

And now, I am off this machine for the evening!
 
Thanks again all. The consensus seems to be that for practical applications, assuming a modern editing platform, only 720 at 60p could make sense, if delivering in that format. Any dissenters?
 
That is interesting. Hadn't thought about the lower bit rate requirements of 720p and the effects on compression. Might be a neat test with a REALLY challenging scene for the compressor.
 
Rob, I think at the end of the day the best approach is to do a little test. Do you have an AF-100? If so then setup a tripod and shoot the same scene in 720p and then 1080p. Put the scene in your editor and create a Flash file, a DVD and a Blu-ray from each resolution. Then watch them all critically and make YOUR decision. This is the only way to truly know what is best and you learn along the way. Post the results in this thread if you do the tests.
 
Bassman2003 said:
Rob, I think at the end of the day the best approach is to do a little test. Do you have an AF-100? If so then setup a tripod and shoot the same scene in 720p and then 1080p. Put the scene in your editor and create a Flash file, a DVD and a Blu-ray from each resolution. Then watch them all critically and make YOUR decision. This is the only way to truly know what is best and you learn along the way. Post the results in this thread if you do the tests.
Click to expand...
And if you don't have an AF100, I bet a nickel one of our members would be glad to shoot a shot in both modes and send you the files.
 
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