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  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

H.264 from RedCine-X...What is the optimal data rate?

M

Meryem Ersoz

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I'm making H.264 Quicktimes from REDCine-X v.11.

Using the H.264 default setting and the default setting was 90 KBytes/sec

This produced files that looked terrible - blocky and unwatchable.

So I clicked off the "Limit data rate" box and pushed Compressor quality to Best (from Medium)

These files look just fine. They are also large, and transcoding at these settings is slow. I might as well be kicking out ProRes, almost.

But there must be an optimal setting between unlimited data rate/Best and 90 Kb/Medium

Does anyone have an optimized data rate for kicking out good clean H.264 files from REDCINE-X?

Somebody must have this. I don't do much DIT work, so all of my transcoding to date has been to ProRes, but I know bunches of you kick out these dailies regularly. What's the secret sauce? (And I don't do enough of this to both with a Matrox Compress HD card or other 3rd-party purchase - I just want to be able to do this with my tower, Rocket, and REDCine)

Thank you, collective brains!
 
well, did my own testing. I wouldn't drop too far below a 2560 kb/sec limit (2.5 mb)

x264 looks nicer but produces files roughly 40% at the same data rate, so a good compromise on a slightly larger file for better quality. if anyone cares...
 
5000 kb/sec is a safe benchmark. Its' approximately DVD quality. I've also seen it be used for broadcast. I would rate 2500 as acceptable. 5000 as good and a base standard, 10,000 as hedging your bets and going for best quality, and 20,000 is going overboard.

Hope this helps.
 
Thanks, Nick - I did test H.264 at 5000 kb/sec and it produced a visibly better quality...but the larger file size was slightly off-putting - I was just wondering what kinds of trade-offs folks were making between quality and file size, in terms of producing dailies which pleased producers. since I have produced several films but am also RED shooter for many years now, I tend to believe the camera guys when they tell me, "it looks sharper in the RAW" - but I'm wondering what qualities people are presenting to non-shooting producers which are pleasing, yet portable...

these are good baseline suggestions. thanks for your input.
 
Meryem Ersoz said:
Thanks, Nick - I did test H.264 at 5000 kb/sec and it produced a visibly better quality...but the larger file size was slightly off-putting - I was just wondering what kinds of trade-offs folks were making between quality and file size, in terms of producing dailies which pleased producers. since I have produced several films but am also RED shooter for many years now, I tend to believe the camera guys when they tell me, "it looks sharper in the RAW" - but I'm wondering what qualities people are presenting to non-shooting producers which are pleasing, yet portable...

these are good baseline suggestions. thanks for your input.
Click to expand...

Another idea is to use "multiple passes" when you make the QT. But that takes forever. Consider using SORENSON SQUEEZE. It has MANY FLAVORS OF .H264. They generate different "looks" (some more contrasty, some less). That's probably a good place to start if you really want to test options on your own. I prefer it much more to compressor. MPEG Streamclip is great too, but doesn't have as many .H264 codecs as Sorenson.

Hope this helps!

- N
 
Skip RCX for H.264!! I'd suggest installing a Matrox Compress HD card, and using Compressor. You can get stellar results at 2Mbps. Small file, great quality, fast process. RCX does not compare.

Von
 
what Von said ... I am generating dailies for ipad after transcoding Avid MXF Files and the datarate of the h264 is 2000 kbit/s max, resolution 720p.
best wishes and kind regards,
martin
 
Von,

by the way- very interesting article.
What kind of MXF do you generate for QCing in Avid Mediacomposer?

best wishes and kind regards,
martin
 
Von Thomas said:
Skip RCX for H.264!! I'd suggest installing a Matrox Compress HD card, and using Compressor. You can get stellar results at 2Mbps. Small file, great quality, fast process. RCX does not compare.

Von
Click to expand...

What are you then using as source in Compressor? I suppose it doesn't take R3D, so do you use a Prores format to render out from there?
Or would it work with the Quicktime Proxies (reference movies) that you render out from RCX?
 
martinnoweck said:
Von,

by the way- very interesting article.
What kind of MXF do you generate for QCing in Avid Mediacomposer?

best wishes and kind regards,
martin
Click to expand...

Thank you Martin. DNxHD 36 all the way to 175, it's all post dependent.

Von
 
Mathieu Ghekiere said:
What are you then using as source in Compressor? I suppose it doesn't take R3D, so do you use a Prores format to render out from there?
Or would it work with the Quicktime Proxies (reference movies) that you render out from RCX?
Click to expand...

Mathieu,

I normally produce ProRes 422 LT, then send that to compressor.

Von
 
Does anyone else have trouble limiting the data rate for H264 when using RCX-Pro? I'm on build 14, and if I set Quicktime to export 480x240 (for quick reference to send to transcriber) and limit the data rate to 500kbps, the file comes out larger than it should be, and quicktime says it's about 2,500kbps.

I'm on on mac pro, 10.5.8.

EDIT: Figured it out. Redcine is in KiloBytes (KB) per second not kilobits (kb) per second. Silly me.

Does anyone know how to compress audio in redcine to something like AAC?
 
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