I have a technical question which is for information only
I know that a HDTV screen is 1080 high and 1920 wide for a total of 2,073,600 pixels (I assume). If it is pixels then how many bits are required to populate a pixel?
Next are there 30 frames per second generated in a tv broadcast.?. or in a blu ray dvd?
bottom line how many bps are necessary to transmit uncompressed hdtv or uncompressed bluray images?
are these transfer rates correct
dvd 10 mbps
ota hdtv 28 mbps
hddvd 30 mbps
bluray 50 mbps
uncompressed hdtv?
standard tv or cable tv?

Or am I stating it wrong?
I have been led to believe that there is more compression in
Cable HDTV than in over the air HDTV and that is more than in bluray. Is that true and if so how much?
These things come up when I am bragging on my blu ray home theater system and I don't want to over or understate the case.
another issue is the difference between the lines of resolution between vhs, dvd, tv and hdtv
I have heard different numbers for that. Are these correct.
vhs = 240 lines
tv = 360 lines
dvd = 480 lines
hdtv 1080 lines
Please correct me where I am wrong.
I probably fall into the category of knowing enough to be dangerous and not enough to be intelligent.
thanks for your help.

Video compression for all of those sources use a variable bit rate, which can vary wildly from scene to scene and the maximum bit rates different for different sources. Broadcast HD is limited to a maximum of 19 Mbps, but often much less is used, and sometimes it is recompressed by satellite providers, etc.

I wouldn't get all caught up in numbers though. Broadcast HD often looks kind of bad because of a number of factors. Because it's limited to MPEG-2 and is often "bit starved" (and is often just run through a compressor without a lot of TLC), you can get pretty nasty compression artifacts in fast moving scenes.

Since prerecorded HD typically uses either a more advanced codec like AVC or VC-1, or a high bit rate (or both), *and* every scene is cafefully tweaked, your Blu-ray or HD-DVD material will usually look a lot better compared to broadcast HD.

There are a ton of other factors, like what transfer was used, etc. It's really not as simple as *just* a numbers game, but bit rate is one important factor.

Forget numbers - if somebody can't see the difference, it hardly matters.

I have a technical question which is for information only
I know that a HDTV screen is 1080 high and 1920 wide for a total of 2,073,600 pixels (I assume). If it is pixels then how many bits are required to populate a pixel?
Next are there 30 frames per second generated in a tv broadcast.?. or in a blu ray dvd?
bottom line how many bps are necessary to transmit uncompressed hdtv or uncompressed bluray images?
are these transfer rates correct
dvd 10 mbps
ota hdtv 28 mbps
hddvd 30 mbps
bluray 50 mbps
uncompressed hdtv?
standard tv or cable tv? It depends on the bit depth, or the number of bits per pixel. Most sources are 8 bit per color, 24 bit per pixel. I believe HDMI 1.3 allows up to 48 bits per pixel, or 16 bits per color.

24 bits per pixel * 2M pixels per frame * 30 frames per second = 1.4B bits per second uncompressed.

I have a technical question which is for information only
I know that a HDTV screen is 1080 high and 1920 wide for a total of 2,073,600 pixels (I assume). If it is pixels then how many bits are required to populate a pixel?
I can clear some of this up for you.

Blu-ray is generally encoded at 1080i or 1080p, which as you say is 1920x1080. It generally uses 8 bit color information across 3 channels so as I understand it that "should" be 24 bits per pixel. However, as mentioned above, the video data is heavily compressed, so the actual amount of data required to represent the 2 million+ pixels is far less than you'd expect.

Next are there 30 frames per second generated in a tv broadcast.?. or in a blu ray dvd?

Most movie and TV sources in North America are NTSC 24 frames per second. Europe and PAL are, I believe standardized on 25 frames per second (which is why PAL / NTSC DVDs had that nasty 4% audio speed differential problem when played on the "wrong" type of player).

Most Blu-ray encoding is on the disc at 1080i/60fps or 1080p/60fps with cadence flags.

bottom line how many bps are necessary to transmit uncompressed hdtv or uncompressed bluray images?

No one uses uncompressed HD signals for broadcast or playback except the content providers who use them to do encoding (and this process usually requires lots of heavy duty specialized hardware and software to handle all the data)


are these transfer rates correct
dvd 10 mbps
ota hdtv 28 mbps
hddvd 30 mbps
bluray 50 mbps
uncompressed hdtv?
standard tv or cable tv?
If we're talking about maximum video bandwidth, then most of your numbers are correct:

DVD 10.01 Mbps
D-VHS ~29Mbps constant bitrate
HD DVD 29.4 Mbps
Blu-ray 40.0 Mbps

I don't know what the over-the-air maximum bandwidth is for certain, but have heard it's around 20Mbps.

Also note that Blu-ray has a lot more headroom than HD DVD. HD DVD's maximum sustained data throughput is 30.24 Mbps, while Blu-ray's is 48.0, with peak values allowed to be somewhat higher.

Or am I stating it wrong?
I have been led to believe that there is more compression in
Cable HDTV than in over the air HDTV and that is more than in bluray. Is that true and if so how much?
In North America, it's definitely true. How true depends on the provider and the Blu-ray encodes in question. Some Blu-ray discs use MPEG-2, so aren't really that much more efficient, though they do use more bandwidth than a broadcast signal, while really stellar encodes like Pirates of the Caribbean : Dead Man's Chest make great use of the available bandwidth and crank it all the way up to 40 Mbps+.


I have heard different numbers for that. Are these correct.
vhs = 240 lines
tv = 360 lines
dvd = 480 lines
hdtv 1080 lines
Please correct me where I am wrong.

I'll refer you to this article:

http://www.hometheaterhifi.com/volume_6_3/essay-video-resolution-july-99.html

...VHS has 220 lines, broadcast TV has about 330, laserdisc weighs in at 400, and our beloved DVD boast 540...

HDTV, both broadcast and HD disc media, are 1080 vertical resolution.

Thank You for your responses and information.
If I understand all this then it seems that we are seeing about 3% of the available information on Blu ray at 30fps and half that at 60fps.
OTA HDTV then is about 1.5% of the uncompressed data, and cable is worse.



At 1080*1920 screen resolution 24 bits/pixels = 2,073,600 total pixels @ 30fps = 1,492,992,000 total uncompressed data /second



transfer rate
48,000,000 = 3.22% Blu Ray
28,000,000 = 1.88% OTA HDTV

Which basically means that as our ability to transmit data grows so does our pq. it can only get better. With something like potc dmc what could that possibly mean.
And Planet Earth should be twice as good on blu ray as on cable hd.

Thank You for your responses and information.
If I understand all this then it seems that we are seeing about 3% of the available information on Blu ray at 30fps and half that at 60fps.
OTA HDTV then is about 1.5% of the uncompressed data, and cable is worse.



At 1080*1920 screen resolution 24 bits/pixels = 2,073,600 total pixels @ 30fps = 1,492,992,000 total uncompressed data /second



transfer rate
48,000,000 = 3.22% Blu Ray
28,000,000 = 1.88% OTA HDTV

Which basically means that as our ability to transmit data grows so does our pq. it can only get better. With something like potc dmc what could that possibly mean.True, but try to remember that advanced codecs such as VC-1 can achieve something like 99% of the visual fidelity of the uncompressed data at a huge fraction of the size and bit rate of uncompressed. There's really no reason to go uncompressed.

Not to mention that if 1 second of uncompressed 1080/30 video take up 1.4GB than an entire 2 hr movie would set you back 10 TB. Where the hell are you going to store that?

Thank You for your responses and information.
If I understand all this then it seems that we are seeing about 3% of the available information on Blu ray at 30fps and half that at 60fps.
OTA HDTV then is about 1.5% of the uncompressed data, and cable is worse.
At 1080*1920 screen resolution 24 bits/pixels = 2,073,600 total pixels @ 30fps = 1,492,992,000 total uncompressed data /second

transfer rate
48,000,000 = 3.22% Blu Ray
28,000,000 = 1.88% OTA HDTV

Which basically means that as our ability to transmit data grows so does our pq. it can only get better. With something like potc dmc what could that possibly mean.
And Planet Earth should be twice as good on blu ray as on cable hd.

No, no, and no. This isn't correct.

Let me give you a better example.

Take a piece of paper and scribble something on it.

Now, take the paper and crumple it up, then un-wad the page. The result still looks a lot like the original, but you've got some damage to the appearance (the folds and crinkles). This is what happens with compression.

Next, take another piece of paper, scribble something on it, and fold it neatly over and over until it's nice and compact. Unfold the page back. You still get some fold lines, but the overall appearance is neater despite the fact that the folded result took up less space. This is roughly analogous to what happens with the newer encoding schemes like AVC and VC-1.

In all cases, the resemblance is pretty striking to the uncompressed original; when you see people talking about transparency, this is what they're referring to.

You're not getting "3%" of the image because of using only 3% of the bandwidth. Rather, you're using compression to greatly approximate 97%+ of the image while using only 3% of the bandwidth.

Does that make more sense?

No, no, and no. This isn't correct.

Let me give you a better example.

Take a piece of paper and scribble something on it.

Now, take the paper and crumple it up, then un-wad the page. The result still looks a lot like the original, but you've got some damage to the appearance (the folds and crinkles). This is what happens with compression.

Next, take another piece of paper, scribble something on it, and fold it neatly over and over until it's nice and compact. Unfold the page back. You still get some fold lines, but the overall appearance is neater despite the fact that the folded result took up less space. This is roughly analogous to what happens with the newer encoding schemes like AVC and VC-1.

In all cases, the resemblance is pretty striking to the uncompressed original; when you see people talking about transparency, this is what they're referring to.

You're not getting "3%" of the image because of using only 3% of the bandwidth. Rather, you're using compression to greatly approximate 97%+ of the image while using only 3% of the bandwidth.

Does that make more sense?

Yes, thanks, I never heard that before. Still I remember a quote from the president of CBS about 2 years ago that hdtv was the worst it would ever be. I thought he was referring to increasing the bandwidth. but the answer may be in the new compression technologies or a combination of both.

live hd feeds are pretty crappy due to real-time compression.