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BitJazz
SheerVideo FAQ
Speed: Production Standards
Is SheerVideo fast enough for HD video?
Is SheerVideo fast enough for SD video?
Is SheerVideo fast enough for film?
 Is SheerVideo fast enough for SD video?
Yes. Even on a mid-range personal computer such as a single-processor 1 GHz Mac G4,
SheerVideo is 5 times as fast (100 MiB/s) as Standard-Definition video (20 MiB/s)
for Y'CbCr 8bv 4:2:2, which has 2 B/p (bytes per pixel).
That's way fast enough for real-time capture and playback.
In fact, it's plenty fast enough to decode 2 SD streams on the fly, composite them, and re-encode the result, all in real time.
For RGB 8b and Y'CbCr 8bv 4:4:4, at 3 B/p,
SheerVideo is 3 times as fast as SD video (30 MiB/s) on a 1-CPU 1 GHz Mac G4.
For more sophisticated editing, using RGBA 8b or Y'CbCrA 8bv 4:4:4:4, which take 4 B/p,
a moderately fast personal computer such as a dual-CPU 1.25 GHz Mac G4
can run SheerVideo more than 6 times as fast (250 MiB/s) as SD video (40 MiB/s).
Of course, on a faster computer, SheerVideo is even faster.
Standard-Definition (SD) video corresponds to 10.368 Mp/s (megapixels per second) or about 9.89 Mip/s (mebipixels per second),
whether NTSC standard, which is 29.97 frames per second at 720 by 480 pixels per frame;
or PAL or SECAM standards, which are 25 frames per second at 720 by 576 pixels per frame.
Keep in mind, however, that being able to do SD video in real time
depends on more than just the speed of the codec and the processor(s).
It's true that SheerVideo's speed and power make it possible to stream uncompressed-quality SD video
to or from an ordinary cheap hard disk in real time.
But if you have multiple video streams,
for example two input streams and one output streams for a typical editing pass,
then each stream needs to be on a different ordinary hard disk if you want to manage without a fast disk array.
And even then, if the video data is fragmented, the disk will still be the bottleneck.
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Is SheerVideo fast enough for HD video? Yes. On a moderately fast personal computer such as a dual-processor 1.25 GHz Mac G4,
SheerVideo is more than twice as fast (250 MiB/s) as
the highest-definition HD Y'CbCr 4:2:2 8b video (120 MiB/s),
and 38% faster than the highest-definition HD RGB 8b or Y'CbCr 8b 4:4:4 (180 MiB/s),
which is ample speed for real-time capture and playback.
On a faster computer, SheerVideo can even make it possible to do real-time HD editing.
High-Definition (HD) video includes a number of different formats,
of which the most demanding is 1920 by 1080 pixels at 30 frames per second,
corresponding to about 62.2 Mp/s (megapixels per second) or 59.3 Mip/s (mebipixels per second).
But SheerVideo doesn't eliminate all the bottlenecks for HD video.
You still need a fast enough RAID array, a fast enough display, and fast enough system and i/o buses.
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Is SheerVideo fast enough for film? Yes, at least for current standard digitized film rates.
The most popular resolution for scanned film today is 2048 x 1152 pixels at 24 frames per second, with a wide-screen aspect ratio of 16:9,
yielding an RGB 8b data rate of 162 MiB/s.
On a moderately fast personal computer such as a dual-processor 1.25 GHz Mac G4,
SheerVideo can process 250 MiB/s, which is more than 50% faster than 2K wide-screen film.
That's fast enough for real-time encoding or decoding.
Real-time digitized film editing, however, will have to await a faster computer.
Of course, at film data rates, there are still many other speed bottlenecks to worry about,
including storage and display devices, and system and i/o buses.
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