James, thanks for the info, i should have made that a bit clearer, i was just giving a ball park figure for a low data rate for a 1080 frame. Sometimes you don't have the time to get the best out of a codec and for delivering graphics or titles i would consider this on the low side of what i would want. But i agree, compression is an art and knowing more about it is always helpful. Cheers,
Andi
To: Avid-L2@yahoogroups.com
From: albion@speakeasy.net
Date: Sat, 22 Oct 2011 11:45:56 -0700
Subject: Re: [Avid-L2] Re: H.264 File Size seems low?
Andi, 4500kbps is completely arbitrary even for 1080/60i. You can stay out of trouble and go quite a bit lower depending upon the content, frame size, frame rate, amount of action in frame, amount of noise,...
Depending upon the H.264 video codec supplier (i.e., Main Concept, etc.) you can have access to a number of different bandwidth controls including: CBR, padded CBR, VBR using peak rate, VBR - Quality Based, and VBR using VBV. One application's VBR might render faster than another's CBR.
But the main consideration is not necessarily the data rate (if the quality is good), but that H.264 MPEG4 is generally a distribution/acquisition format due mostly to it's inter-frame (across multiple frames) compression which leads to inefficiencies in random access of individual frames (not good for editing). While ProRes and similar use intra-frame compression which is much more efficient for editing. [H.264 also has a highly efficient intra-frame compression implementation, hence Panasonic's AVC-Intra acquisition codec.]
Another consideration is that current implementations of H.264, are still limited to 4:2:0 chroma sampling, and 8-bit color. Though the MPEG-4 spec (of which H.264 is a part) supports 4:2:2/4:4:4 chroma sampling and higher bit-depths in theory.
James
On Oct 22, 2011, at 10:55 AM, Andi Meek wrote:
> Bring up the inspector (Apple+I or Ctrl+I). this will tell you the data rate. The lower the data rate, the higher the compression, the smaller the file, what data rate have they used to compress the file? For an HD frame size anything below 4500kbps is asking for trouble. H.264 is VBR I think so it probably didn't save them any time encoding it, it may have taken them more time than if they used a CBR codec like ProRes, especially if they did more than one pass. Likewise if there's lots of noise all over the frame then using Animation wouldn't be a great option either as the run length encoding that animation uses only compresses efficiently if there is not much changing from frame to frame. I would have thought that the best option would have been Prores HQ or completely uncompressed. Ask for it again, they're a graphics company so they should know better and if they don't then they should learn a lesson!
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> Cheers,
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> Andi
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> To: Avid-L2@yahoogroups.com
> From: bigfish@pacbell.net
> Date: Sat, 22 Oct 2011 04:54:24 +0000
> Subject: [Avid-L2] Re: H.264 File Size seems low?
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> Saving it from a small original isn't really going to gain me anything. I just want to make sure I'm not getting an inferior product. I'm just not use to a file being this small for 24 secs of 1080I. But from what others have said it's not that uncommon. This is a graphic open title sequence so it shouldn't be delivered in an overly compressed form in my opinion. I can't see any problems with it but they put a bunch of noise effect on the video so it's really hard to tell. A part of me feels like I've just been handed a VHS tape for my graphic master but with a file I can only go by the file size as an indicator of how compressed it might be.
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> --- In Avid-L2@yahoogroups.com, Benjamin Hershleder <Ben@...> wrote:
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>> John, if you're worried, save it out as ProRes HQ.
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>> Benjamin Hershleder
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>> http://ContactBen.com
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>> http://Hershleder.com
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>> Wear It In Post!
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>> Fun T-shirts, mousepads, mugs & more
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>> for Post Production Professionals
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>> http://www.WearItInPost.com
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>> On Oct 21, 2011, at 9:24 PM, James Culbertson wrote:
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>>> That's not a particularly low data rate for well compressed H.264. Some content at that length could be taken down substantially below 10 MB if it is clean.
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>>> James
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>>> On Oct 21, 2011, at 8:32 PM, johnrobmoore wrote:
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>>>> Finder Info shows the same size as QT. It just seems like a low number for 24 secs of 1080I video.
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>>>> --- In Avid-L2@yahoogroups.com, Tim McLaughlin <mcltim.156@> wrote:
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>>>>> Forget what Quicktime says - what dies the Finder say? Get info on the file.
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>>>>> I've found Quicktime to be just flat-out WRONG a lot of the time. The Finder
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>>>>> is never wrong.
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>>>>> --
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>>>>> Tim McLaughlin
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>>>>> Final Cut and Avid Editor
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>>>>> http://vimeo.com/mcltim
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>>>>> www.mcltim.com
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>>>>>
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>>>>>
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>>>>> On Fri, Oct 21, 2011 at 7:02 PM, John Moore <bigfish@> wrote:
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>>>>>> **
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>>>>>> I have a 24 second .mov file for final delivery and the file size is 57.60
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>>>>>> MB according to QT 7. Format is H.264 1920x1080. Millions AAC. Stereo (LR)
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>>>>>> 48.000 KHz
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>>>>>> FPS: 29.97. This seems really small for 24 secs of 1080I HD video. This
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>>>>>> is video with noise to make it look like a 70's/80's sitcom open. I usually
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>>>>>> expect around a gig a minute for full res files, obviously this varies but
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>>>>>> my ball park says it should be around 400MB not 57. The video is live
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>>>>>> action stuff so it's not some super optimized graphic element. I'm told the
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>>>>>> graphics company are young kids so you decide what that means. I said we
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>>>>>> need an uncompressed .mov in animation at best or prores. This is for an HD
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>>>>>> 1080I 59.94 HDCam delivery to a cable network so I think this file isn't up
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>>>>>> to snuff. Given all the noise and grain crap in the video it might not
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>>>>>> really make much difference but I want a bigger file to compare. Am I
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>>>>>> nuts? I hate to think that the graphics company is trying to save render
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>>>>>> time and upload time at the expense of quality. I don't usually think of
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>>>>>> H.264 as the proper format to deliver graphic elements for an
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>>>>>> online edit but I'm sure there are many flavors of H.264 I'm just use to
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>>>>>> getting highly compressed versions for approval. Any insight as to
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>>>>>> something I'm overlooking here would be appreciated.
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>>>>>>
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>>>>>> John Moore
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>>>>>>
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>>>>>> Barking Trout Productions
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>>>>>> Studio City, CA
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>>>>>> bigfish@
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>>> Search the official Complete Avid-L archives at: http://archives.bengrosser.com/avid/
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>>> Yahoo! Groups Links
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> Search the official Complete Avid-L archives at: http://archives.bengrosser.com/avid/
> Yahoo! Groups Links
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