I'm confused about HD

[alegator]

Whenever I capture videos from the Sony HC3 I see that 1 hour of HD 1080i video creates a file of size 13Gb approx.,i.e., exactly the same as that produced by a DV-AVI file captured from a Sony TRV950. So then, why is it that one needs a 60Gb Blu Ray DVD to store a HD video? Is it because it cannot be further compressed to 4gb/hour as a regular DV-AVI can when authoring to DVD?? And in terms of hard drive space, then the demands for storing raw captured HD video in hard drives is exactly identical to those of DV-AVI files? Thanks.

[edDV]

Whenever I capture videos from the Sony HC3 I see that 1 hour of HD 1080i video creates a file of size 13Gb approx.,i.e., exactly the same as that produced by a DV-AVI file captured from a Sony TRV950. So then, why is it that one needs a 60Gb Blu Ray DVD to store a HD video? Is it because it cannot be further compressed to 4gb/hour as a regular DV-AVI can when authoring to DVD?? And in terms of hard drive space, then the demands for storing raw captured HD video in hard drives is exactly identical to those of DV-AVI files? Thanks.

Let's try to answer this way

DV video is all I frames 720x480i 4:1:1 @25Mb/s
HDV is MPeg2 (medium GOP) 1440x1080i or 1280x720p 4:2:0 @25Mb/s

DVD is MPeg2 (long GOP) 720x480i or 720x480p 4:2:0 @ 3-8Mb/s
HD/BD DVD is MPeg2 (long GOP) 1920x1080p/24fps 4:2:0 @ 19-25 Mb/s or
HD/BD DVD is MPeg4* (long GOP) 1920x1080p/24fps 4:2:0 @ 8-16 Mb/s
*VC-1 or MPeg4 AVC H.264

ATSC SD is similar to DVD
ATSC HD is MPeg2 (long GOP) 1920x1080i/29.97fps 4:2:0 @ 14-19 Mb/s or
ATSC HD is MPeg2 (long GOP) 1920x1080p/24fps 4:2:0 @ 19 Mb/s (rarely used) or
ATSC HD is MPeg2 (long GOP) 1280x720p/59.94fps 4:2:0 @ 14-19 Mb/s

So HD MPeg2 and HDV and DV take up lots of disc space
VC-1/H.264 take up about half the disc space of MPeg2.

VC-1 and/or H.264 are expected to be approved as secondary channels on ATSC at some future point (new tuners required).

[alegator]

Ed, thanks for that info. But then what I thought is correct. If I store raw captured HDV video it will require the same hard drive space per unit time as DV video. On the other hand HD DVD requires around 4 to 5 times more space than DV DVD, therefore explaining the need for higher capacity DVD's. But again, at the hard drive level when one captures, I will still need about 13Gb of space per hour of video for both DV and HDV.

[edDV]

Ed, thanks for that info. But then what I thought is correct. If I store raw captured HDV video it will require the same hard drive space per unit time as DV video. On the other hand HD DVD requires around 4 to 5 times more space than DV DVD, therefore explaining the need for higher capacity DVD's. But again, at the hard drive level when one captures, I will still need about 13Gb of space per hour of video for both DV and HDV.

Yes, even though HD/BD DVD is higher resolution 1920x1080p, film is stored at lower 24 fps and with more compression.

HDV is 1440x1080i or 1280x720p and operates at higher frame rate and lower compression. This makes for better handheld and editing performance.

DV is standard definition 720x480i but is much less compressed and includes every entact frame plus audio is uncompressed PCM.

All three consume about the same bitrate (18-25Mb/s*) and disk space (9-13.5GB/hr.).

*plus audio.


Think of MPeg4 (H.264 or VC-1) as a higher compressed but equal quality archive format. It uses about half the disc space for HD (~ 4-7GB/hr.) and much less for SD.