DVCPro HD bit rates/resolutions/frame rates

[Terry_g_johnson]

If my calculations and assumptions are right (for 720p60):

100 Mbps / 60 Fps = 1.666 Mb/F
F = 720 X 960 Px = .691 M Px

1.666 Mb/F =1.666 Mb /.691 M Px = 2.4 b/Px

or 2.4 bits per Pixal prior to compresson

[Terry_g_johnson]

Correction 2.4 bits per pixel After compression.

[Terry_g_johnson]

When I follow the same process for basic DV recording I get the identical result of 2.41 Bits/Pixel

If you assume that the Sony HDV records at 1080 X 1440 with a data rate of 25Mbs you get 0.537 Bits/Pixel.

If my calculations are right then DV & DVCProHD have 2.41/0.537=4.49 times as much data recorded per Pixel.

[Jason J rodriguez]

See, that’s very unfortuate that Panasonic must do things that way with the constant bit-rate rather than maximizing the bit rate of 100Mb/s for each frame-rate, like Sony does. HDCAM, for example, is 6Mbits/frame (@24p), yielding much less compression artifacting, especially at 1920×1080, than DVCProHD.

Jason Rodriguez
Virginia Beach, VA

[Dom Silverio]

It is not quite apples to apples.

First you need to consider that HDV and DVC Pro uses 2 different compression system – DCT vs MPEG.

Second DVC Pro is not full raster. At 720p, DVC Pro HD sample only form 960 lines in the luma channel and 480 lines in the chroma channel. So the data rate is only part of the story. DV25 samples from full res in both Y and C channels.

So comparing HDV and DVC Pro HD is not easy. I still prefer DVC PRo HD [easier to edit and 4:2:2] but shear data rate does not reveal why DVC Pro HD is superior.

[Guy Barwood]

Is there any cahnce we could summarise all this back in some table format of frame rates and resolutions? It got a bit consfusing after a few posts.

Cheers

Guy

[Guy Barwood]

So is this correct?:

720p (1.666Mb/f) (record time on a single 4GB* P2 Card)
960x720p 24fps 40 Mbps (14min)
960x720p 25fps 41.6 Mbps (13.4min)
960x720p 30fps 50 Mbps (11.2min)
960x720p 48fps 80 Mbps (7min)
960x720p 50fps 83.3 Mbps (6.7Min)
960x720p 60fps 100 Mbps (5.6min)

1080i (3.33Mb/f)
1280×1080 24fps 80Mbps (7min)
1280×1080 25fps 83.3Mbps (6.7min)
1280×1080 30fps 100Mbps (5.6min)

If it is correct, which, if any does the HVX200 NOT support (if it is known yet).

*Using 1GB = 1024MB

[Toke]

Doesn’t mpeg use dct?

[Graeme Nattress]

Yes, MPEG2 is DCT based.

Graeme

– http://www.nattress.com – Film Effects for FCP

[Dom Silverio]

Well I should be more accurate then

DV is I Frame only DCT compression unlike HDV 🙂