h.264 to prores 422 (proxy) workflow

I accidentally posted this in Cafe LA forum, sorry for the cross post. I think this is the right place.

I've searched all over and found really good information about prores, prores proxy but still have a lot to learn about codecs. I haven't been able to find the answer, or maybe didn't understand what I read on my specific situation.

I have a Sanyo FH1, shooting in 1080p/30. It creates mp4 files h.264 encoded. I've been working with them on my macbook pro (4Gb) and they are a little slow to render. After reading up on this, I saw in the lafcpug newsletter an article on working on a macbook pro using prores 422 proxy. I tried it out and it seemed to be a little faster rendering, played RT better for sure and the file sizes were about the same as the original.

Here's my questions.

1> aside from the render time / RT difference (maybe 5%), is there an advantage to editing in 422 or 422 proxy? Is the quality better?

2> when I recompress my h.264 to prores 422 proxy using media manager, do I just edit in that format and then relink my project to the original h.264 clips or should I convert my originals into prores 422 AND prores 422 proxy files and archive the h.264 original files? I can't imagine that converting from h.264 to prores 422 would improve the quality.

I view my movies on a 52" 1080p LCD TV and it looks great without dealing with prores but it would be nice if I could convert all clips to one format before editing to make sure I have the fastest editing workflow possible.

Thanks in advance for the input (especially on #2 above).

Alright, for the record, it's H.264.

>I can't imagine that converting from a.264 to prores 422 would improve the quality.

It doesn't, but as you noticed, it speeds up your rendering time, and gives you much better RT performance. H.264 is a very compressed format, and heavily processor intensive to work with. ProRes is an intermediate codec (or as Apple will refer to it as a "Post Production codec". ProRes is designed to withstand numerous generation hits without visibly losing quality, also, it is virtually indistinguishable from Uncompressed.

>when I recompress my a.264 to prores 422 proxy using media manager, do I just edit in that
>format and then relink my project to the original a.264 clips or should I convert my originals
>into prores 422 AND prores 422 proxy files and archive the a.264 original files?

You can use Compressor for that purpose. It's much faster than media manager. You should always keep a copy of whatever the camera generates as that's your source. Whenever you have any issues with the transcoding, you go back and check your source. Convert everything to ProRes, edit and finish in ProRes.

I haven't tried ProRes Proxy, but it's created for offline cuts. You could try going to ProRes LT. That's probably about 4 times the size of your H.264 source, but the quality should be better than ProRes Proxy. If you can afford the storage to transcode to ProRes, all the better.



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Thanks, yeah I caught my a.264/h.264 blunder after I posted and changed it. No wonder some of my searches were coming up empty

I'll try to switch to compressor and try out 422LT.

My thought on proxy was that I could convert the H.264 source files to the offline proxy files (since I only have a macbook pro to edit on), and then re-point the project back to my source files after editing to re-gain the quality lost from the proxy conversion before final output. I'm trying to figure out if there's an advantage to converting my source files to the 422 or 422LT if I use the proxy workflow as I would only be using those files once I re-point my project to them. -- not sure if that makes sense.

Here's the options for workflow I'm thinking of:
option 1>
convert h.264 files to 422 Proxy
edit with 422 Proxy files
relink project back to h.264 files
output
option 2>
convert h.264 files to 422 (or 422 LT) AND 422 Proxy
edit with 422 Proxy files
relink project back to 422 (or 422 LT) files
output
option 3>
convert h.264 files to 422 LT
edit with 422 LT files
output

I keep thinking that option 1 seems to be the way to go.... but again, I don't know much yet. Option 3 seems the most simple. I'm afraid the data rate of 422 or 422LT is too much for my macbook pro though.

Thanks for your response.

Option 1 is not good. FCP isn't designed to work well with H.264.

Option 2... Well, that defeats the point of transcoding if you're going to transcode twice.

If you have the space for ProRes, I'd go to ProRes directly, cut and output from there.


>I'm afraid the data rate of 422 or 422LT is too much for my macbook pro though.

Have you tried? There's no issues, as long as your drive is fast enough to handle ProRes. ProRes LT shouldn't be a problem at all. It's the same data rate as DvcproHD, which heck, you can even cut on single USB 2.0 drives at that bit rate.



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