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big 4 second video
I’m making a 4 second video to study pixilation questions. It will be made from a hundred 2000×1500 8-bit greyscale bitmaps. I plan to import these into FCP to make a 25P video loop. It must have the exact original grey values at each pixel. It will be viewed at 2000×1500 on a monitor.
Using codec “None” the data rate will be about 75 MB/sec which is probably too high for my non-RAID hard drive. Since the images have very large areas of white, more than 90% of the frame, a codec with really lossless compression would seem suitable. Which codec is recommended? Is QuickTime the best player?
If not for the looping the whole video would be just 300 MB. It could reside in RAM and avoid the hard drive read rate limitation. Can one make a player do this?
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13 Replies
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I used to Make RAM Disc way back when with OS 9, here are a couple of things that came up in google. I have never tried either so I’m just passing on the info, not saying these will work.
https://osxdaily.com/2007/03/23/create-a-ram-disk-in-mac-os-x/
https://www.versiontracker.com/dyn/moreinfo/macosx/20947
Instead of using codec NONE, try using 10 Bit Uncompressed, I believe it should be about 1/2 the size. ProRes is a good compressed codec, it is 10-bit but any compression is going to be a compromise.
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[Dennis Couzin] “I plan to import these into FCP to make a 25P video loop. It must have the exact original grey values at each pixel. It will be viewed at 2000×1500 on a monitor. “
Ok backup a bit.
Max frame size in FCP is currently 2048 x 1152 so you will not be able to output the files as video. Look into After Affects.“Using codec “None” the data rate will be about 75 MB/sec which is probably too high for my non-RAID hard drive.”
Did you miss a zero in that number? My calculator says that “None”file is closer to 750MB/s at that frame size.
if you are planning on staying as 8 bit the 8bit Uncompressed codec should be fine and would be able to play realtime once cached into ram.
[Dennis Couzin] ” Is QuickTime the best player? “
if you are doing a scientific analysis – no- it will self compensate for variance in the frame rate and image size.if you need correct and steady playback you will need to modify your procedures to handle the file correctly as video (not as a computer monitor as indicated)
gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsCheck out
https://www.aja.com/kiprotour/Inside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
Michael, thanks for that lead to Make RAM Disc.
The suggestion about 10-bit uncompressed doesn’t work however. For a color video, 8-bit uncompressed would indeed be half the size of (8-bit) None. But for a monochrome video like mine, there is no advantage to doing 4:2:2 subsampling. Rather there is a disadvantage to using a 4:2:2 codec since it will stick in unnecessary zeros for the chroma. The None codec as implemented by Compressor allows me to code as greyscale. Then None uses just 8 bits per pixel, versus 16 bits per average pixel used by 8-bit uncompressed 4:2:2. I just made QuickTimes both ways and sure enough the None file is half the size of the 8-bit uncompressed 4:2:2 file. -
Gary, thanks for the info that maximum FCP size is 2048 x 1152. Luckily I constructed the experiment in such a way that I can still crop all the 2000 x 1500 bitmaps down to 2000 x 1152.
My arithmetic checks. I’m using codec None as 8-bit grayscale, which is what the bitmaps are. A 2000×1500 8-bit grayscale image requires just 3 million bytes. That’s 75 million bytes per second, 71.5 MB/sec if you will. Did you calculate for bits instead of bytes? Hard drive read speed is generally specified in MB/sec.
Now cut down to 2000×1152 the demand will be just 55 MB/sec. Maybe my Samsung HD103UJ can do it!
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Gary, I just checked and verified that I already made a video in FCP with 2048×1536 pixels. I described that clip in a long ago discussion strand. Apparently your figure of 2048×1152 is the limit for 16:9 format video only. FCP can handle more total pixels than that in 4:3 format. At least my FCP 5.1.4 can.
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[Dennis Couzin] “Gary, I just checked and verified that I already made a video in FCP with 2048×1536 pixels. I described that clip in a long ago discussion strand. Apparently your figure of 2048×1152 is the limit for 16:9 format video only.”
Actually it is the max size that can be output as a SMPTE video signal from within Final Cut as an application, I stated this because you said you were making VIDEO, and that is the max size for a SMPTE video signal to be passed over dual link.
However you are just within the 2048x 1566 frame size that is the max allowed within FCP.
As for the video in None codec, no I created a file in AE that was 2000x 1500 as RGB and saved as non- codec and I still get 750MB/s for the data rate- NOT the size of the file.
My 4 second clip at 2048X1566 (RGB) saved as ” NONE” from AE was over 1.2G in size, So I do not understand where and how you got those sizes for your files, as they are not what I am looking at.
gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsCheck out
https://www.aja.com/kiprotour/Inside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
Gary, what I called a video was also described as being played by QuickTime on a monitor so it was a leap to assume it to be “SMPTE video signal to be passed over dual link.” I won’t contribute to the semantical debate over what is video and what is electronic cinema except to note that the narrow usage of “video” is sure to die as video appears everywhere — even cellphones make videos.
Concerning the file sizes and byte rates my calculations are correct. You speak of 2000×1500 RGB. That requires at least 24 bits per pixel — see below. I’m speaking of 8-bit grayscale requiring just 8 bits per pixel. As noted, Compressor implements the “None” codec with a 256 graytone depth option. That’s 8-bit grayscale. For verification I just now made a 2000×1500 8-bit grayscale clip in “None” using Compressor v.2.3. It’s 1.88 seconds long and 134.5 MB. That’s 71.5 MB/sec, exactly as was calculated.
It would be absurd if the “None” codec produced files substantially larger than the sum of the bitmap files for its frames, providing the pixel count and the bit depth didn’t change.
The reason your 4 second “None” clip from 2048X1566 RGB was so large is that 4 X 24 X 2048 X 1566 X 32 = 9.85 billion bits, which is 1.23 billion bytes. You made what Compressor calls “Millions of Colors+” for 32 bit pixel depth. If AE can only make 32-bit “None” files that’s a problem of AE. Compressor’s implementaton of codec “None” allows the following depths:
1-bit (Black/White)
2-bit (4 greys)
2-bit (4 colors – doesn’t work!)
4-bit (16 greys)
4-bit (16 colors – has a bug!)
8-bit (256 greys)
8-bit (256 colors)
16-bit (thousands of colors)
24-bit (millions of colors)
32-bit (millions of colors + alpha)All of this was discussed, including the calculation of file sizes in my Feb 20, 2009 post: funny codec named “None”, and in the ensuing strand to which you contributed.
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[Dennis Couzin] “Gary, what I called a video was also described as being played by QuickTime on a monitor so it was a leap to assume it to be “SMPTE video signal to be passed over dual link.”
Actually you did not tie those 2 thoughts together until after my first couple of posts, and no it is not a leap when I have no idea what your usage is and I was relaying the limitations of the video signal you described as it would be handled inside of FCP.
I paid no regard to your specific issue, which is still very very vague. Frames of your stated raster size only are allowed over a dual link signal when we are talking about video from a video editing application.
[Dennis Couzin] ” If AE can only make 32-bit “None” files that’s a problem of AE. “
AE has far more control than Compressor does with regard to bit depth handling and metric controls that are all pre compression- the Apple tool is very limited by comparison.
and thanks for the lecture.
gary adcock
Studio37
HD & Film Consultation
Post and Production WorkflowsCheck out
https://www.aja.com/kiprotour/Inside look at the IoHD
https://library.creativecow.net/articles/adcock_gary/AJAIOHD.php -
Gary Adcock,
Your original answer consisted of three parts:Part 1: “Max frame size in FCP is currently 2048 x 1152 so you will not be able to output the [2000×1500] files as video.”
This part was off due to your misunderstanding of my use of the word “video”, though I did mention QuickTime player in my original post.
Part 2: “Did you miss a zero in that number? My calculator says that “None”file is closer to 750MB/s at that frame size.”
This part was off due to your making a 32 bit None file although my original post clearly says my images are 8 bit grayscale.
Part 3: “…if you are doing a scientific analysis – no- [QuickTime] will self compensate for variance in the frame rate and image size. if you need correct and steady playback you will need to modify your procedures to handle the file correctly as video (not as a computer monitor as indicated)”
I’m not sure what this part means but will take it seriously. What variance in frame rate are you referring too? My “None” file will have 25 full frames per second. Won’t QT display 25 full frames per second? It’s a Samsung 305T monitor and a Nvidia 7300GT graphics card. What funny things can these do temporally? As for image size, I intend to display the 2000×1500 on exactly 2000×1500 pixels. QuickTime and the 305T allow that. What can go wrong there? Concerning “scientific analysis” (your term) it will be a purely visual experiment. No measurement will be taken off the screen. But even for visual appearance if the system introduces dithering or sharpening or noise reduction, or anything that is not there in the bitmaps, my experiment could be in trouble. (I am prepared to go back and play with the bitmaps’ gamma curve in Photoshop after seeing what FCP/Compressor does in the None conversion.)
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Make RAM Disk 1.0 by Peter Hosey works beautifully in my 2007 Mac Pro running OS 10.4.11.
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