HDV Motion Artifacting

[Specialist]

Nice article about HDV's motion artifacting problem:

http://tinyurl.com/eqnzu

Motion, especially fast-moving and detailed motion as in sports footage, presents quite a challenge for the real-time MPEG encoders in standard HDV cameras. It’s a challenge HDV can often meet, but not always. This is the downside of HDV’s impressive MPEG compression efficiency.

I've been looking at some video shot by a fellow who uses a Sony HDV camcorder and he's disappointed with the level of artifacting on horizontal motion.

And there's really nothing that can be done about it as far as I know.

There's also an annoying "rolling shutter" effect being reported by users of Sony's low-end HDV camcorders:

http://tinyurl.com/r4qbb

Jerry Jones
http://www.jonesgroup.net

[Wile_E]

I have a simple solution. Less compression. I knew they rushed all this HDTV and HDV stuff too soon. I see bad artifacts everytime I see a HDTV in action. The last few football games I watched looked terrible. Blocks could be seen between transitions and in fast motion. The broadcasting industry wanted to rush this stuff to make money, and now it's showing. HD needs more bandwidth, and less compression. They should've waited a few more years to roll out HDV and HDTV, until the techology matured.

[edDV]

I have a simple solution. Less compression. I knew they rushed all this HDTV and HDV stuff too soon. I see bad artifacts everytime I see a HDTV in action. The last few football games I watched looked terrible. Blocks could be seen between transitions and in fast motion. The broadcasting industry wanted to rush this stuff to make money, and now it's showing. HD needs more bandwidth, and less compression. They should've waited a few more years to roll out HDV and HDTV, until the techology matured.

The broadcasters are doing fine up to the last few steps in the process where uncompressed SMPTE 292M (1.5 Gb/s) goes to HDCAM (143Mb/s) or DVCProHD (100Mb/s). Next comes downlink to the DTV station at ~44 Mb/s and then transmission at 14-19 Mb/s to the home.

Somewhere in the 100x compression artifacts can surface.

That article is tossing out red herrings. I've never heard of anybody taking 25Mb/s HDV seriously for shooting sports. It can be near average with 1440x1080i/29.97 or 1280x720p/29.97 but it won't do 1280x720p/59.94 like used on ABC, FOX or ESPN.

Also, HDV encodes in the camera with relatively cheap hardware Mpeg encoders, where serious broadcasters are shooting uncompressed and encoding in expensive hardware downstream.

[edDV]

I have a simple solution. Less compression.

Less compression was never an option. The goal of ATSC DTV was not optimal picture quality, it was a ~50% reduction in RF spectrum devoted to television without reducing the number of channels broadcast in a typical city. ASTC DTV allows closer channel spacing and less interference. HDTV picture quality was never the primary issue. The only issue was HDTV had to fit in 6MHz of RF bandwidth. Period.

Congress wants spectrum to go to telecommunications wireless services and away from television.

The 911 commission keeps making noises about wanting to turn analog TV off now to allow for improvement in emergency communications. The NAB wants to leave it on until 2009.

[MozartMan]

Hey specialist

1. There is nothing new about MPEG-2 motion artifacting.
1. That article is 8 months old.
2. Why do you hate HDV so much?

[DereX888]

...and to think that some people suggested I should wear *new* glasses (like I had any ever) when I said I was disappointed with visible artifacts in HD broadcast few years back LOL
I should PM them this article with pic of my middle finger att'd lol

Anyways old story, its been discussed all over in the past.
I thought they have come with solution of delaying broadcast for 10 or so seconds for live broadcasts, didnt they?

Commissions, NAB, whatever - they cant just force people to throw away some half a billion working analog TVs in USA alone
Watch me watching local analog broadcasts in at least next 10 years, wanna bet?

[edDV]

...
I thought they have come with solution of delaying broadcast for 10 or so seconds for live broadcasts, didnt they?

Serious MPeg2 encoders have delay. Multi-subchannel encoding can be improved by sharing bandwidth based on motion (statistical multiplex). Total processing delay can reach 30-40 seconds. Most of this delay happens at the local DTV station.

...
Commissions, NAB, whatever - they cant just force people to throw away some half a billion working analog TVs in USA alone
Watch me watching local analog broadcasts in at least next 10 years, wanna bet?

No reason to throw away an analog TV. The old NTSC tuner will be useless. Just add an external ATSC DTV tuner (looks like a cable box) and your old TV will receive all the new channels. These tuners are due for serious price drops before 2009.

Find your DTV channels by entering your address into www.antennaweb.org

[DereX888]

...
I thought they have come with solution of delaying broadcast for 10 or so seconds for live broadcasts, didnt they?

Serious MPeg2 encoders have delay. Multi-subchannel encoding can be improved by sharing bandwidth based on motion (statistical multiplex). Total processing delay can reach 30-40 seconds. Most of this delay happens at the local DTV station.

...
Commissions, NAB, whatever - they cant just force people to throw away some half a billion working analog TVs in USA alone
Watch me watching local analog broadcasts in at least next 10 years, wanna bet?

No reason to throw away an analog TV. The old NTSC tuner will be useless. Just add an external ATSC DTV tuner (looks like a cable box) and your old TV will receive all the new channels. These tuners are due for serious price drops before 2009.

Find your DTV channels by entering your address into www.antennaweb.org

I should have rephrased my sentence.
Why some TWO HUNDRED MILLION people should pay for external tuner/decoder?
Even if they drop to $10 a piece (which I doubt they ever will in next 10-15 years), its a $2 billion dollar business at least up for grabs...

[edDV]

...
I thought they have come with solution of delaying broadcast for 10 or so seconds for live broadcasts, didnt they?

Serious MPeg2 encoders have delay. Multi-subchannel encoding can be improved by sharing bandwidth based on motion (statistical multiplex). Total processing delay can reach 30-40 seconds. Most of this delay happens at the local DTV station.

...
Commissions, NAB, whatever - they cant just force people to throw away some half a billion working analog TVs in USA alone
Watch me watching local analog broadcasts in at least next 10 years, wanna bet?

No reason to throw away an analog TV. The old NTSC tuner will be useless. Just add an external ATSC DTV tuner (looks like a cable box) and your old TV will receive all the new channels. These tuners are due for serious price drops before 2009.

Find your DTV channels by entering your address into www.antennaweb.org

I should have rephrased my sentence.
Why some TWO HUNDRED MILLION people should pay for external tuner/decoder?
Even if they drop to $10 a piece (which I doubt they ever will in next 10-15 years), its a $2 billion dollar business at least up for grabs...

First Congress (both parties), the computer industry and the telcos are pushing the plan, the broadcasters have been against it because it is expensive for them. Second, 85% of US TV sets are already hooked up to cable or dbs and hence are not affected. Third, expect prices for the analog out models to fall to the $30-45 range by 2009. There will be many promos to offer them free or near free.

If you are a cellular or wireless computer user, or a user of police, fire or transportation services you are really to blame. Get off those electronic gizmos and stop calling 911!

[DereX888]

Well. I won't argue that.
Just imagine those half a billion analog tvs (or even just half of them) ending in the landfills in next few years... So much pollution just to have sharper view of advertised products on new Home Commercials and Brainwash Delivery Systems

[BJ_M]

they will just ship them to cuba

[Specialist]

Hey specialist

1. There is nothing new about MPEG-2 motion artifacting.
1. That article is 8 months old.
2. Why do you hate HDV so much?

I don't "hate" HDV.

I'm just surprised by the raw HDV clips I've viewed.

Prior to the release of this format, I would not have believed that they would release camcorders that do such a poor job with motion.

You're right that MPEG-2 motion artifacting is not new.

But what really shocks me is how *bad* the HDV motion artifacting looks when you down-convert to standard definition NTSC DVD.

I've read a lot of posts from individuals who have long claimed that down-converted HDV looks "better" than standard definition DV converted to NTSC DVD.

Now that I've done a lot of testing, I think it's the other way around.

In my tests, the standard definition DV converted to NTSC DVD seems to handle motion far better than the HDV format down-converted to NTSC DVD.

Try shooting a string of cars driving down any street and compare the horizontal motion between HDV and DV.

It's really quite shocking to see how poorly HDV performs.

I'm hoping the AVCHD doesn't suffer from the motion artifacting problems to this degree.

For me, HDV is a perfect format for somebody who's just going to shoot family birthday parties and camping trips and stuff that doesn't force you to capture a lot of motion.

Sports?

Forget it; HDV isn't a good fit for that type of shooting.

If one has to have the higher resolution of HDV, then fine.

But when it comes to making standard definition DVDs, the DV format is still my favorite.

I would never buy an HDV camcorder with the goal of making standard definition DVDs because the motion problems -- for me -- are just too apparent.

The other thing I don't understand about the companies that are making the HDV camcorders is why they're largely choosing 1080/30i over 720/60p.

If one wants to watch very pretty progressive frame video, then 720/60p makes a lot of sense and it's why ABC and ESPN use it for sports.

But the only reason why one would want 1080i would be to view the end result on an interlaced tube HDTV, in my opinion.

Otherwise, give me a progressive camcorder.

That's how I see it at this point in time.

Jerry Jones
http://www.jonesgroup.net

[Specialist]

More about how to minimize the HDV horizontal motion artifacting problem here:

http://tinyurl.com/h6qwu

Shooting with the Sony HDR-FX1, we noticed that the image quality, although generally very good, becomes a bit noisy (or blurred) when we panned with the camera. Actually, this is quite typical for MPEG-2 compression, even in HD broadcasts, as we noticed in the Summer Olympics broadcasts. With the HDR-FX1, the blur/noise is more visible because it features a less expensive codec. Using an HD-SDI converter, we then hooked up the camera with a portable HDCAM deck (SONY HDW-250). This let us bypass the MPEG-2 codec (with a transfer rate of 25 Mbps) and, instead, record uncompressed HD (with a rate of 140 Mbps). This resulted in a higher image quality with relatively clean pans. Based on our experience, we also recommend minimizing horizontal movement (panning) as much as possible in order to maintain a clean image. If you need to pan (and want to maintain the image quality), always pan as slowly as possible!

Jerry Jones
http://www.jonesgroup.net

[BJ_M]

If you need to pan (and want to maintain the image quality), always pan as slowly as possible!

geez - what insight !!!

same thing goes for any format -- and one reason I really can't stand watching 24fps film in most theaters as the pans look sick .... i really wish the standard had been raised when we had the chance (for HD) ... 24fps really sucks.

anyway - this is not news and moving topic

[MozartMan]

-- and one reason I really can't stand watching 24fps film in most theaters as the pans look sick .... 24fps really sucks.

ditto

[edDV]

Everything is a tradeoff. A good workman uses the right tools (and video formats).

25Mb/s 720x480i DV has low DCT intraframe compression and entact frames (perfect motion) and is great for SD sports although interlaced.

25Mb/s 1280x720p HDV has ~4x more intraframe compression and MPeg motion compression.
25Mb/s 1440x1080i HDV has ~6x more intraframe compression and even more MPeg motion compression.

The latter two get you more resolution for locked camera shots but also higher motion artifacting. Keep in mind that MPeg2 encoding for DVD is going to have similar potential motion artifacts but these are easier to fix in post with image processing tricks.

DVCProHD 100Mb/s 960x720p @59.94 fps is what you want for sports (motion detail). The least expensive camcorder is the Panasonic HVX-200 @$6000 + ~$2000 for either P2 cards or a special external harddrive to record the 100Mb/s stream.

The trick mentioned above for bypassing the HDV MPeg2 encoder in the Sony HDR-FX1 to a HDCAM deck could be done in theory to an uncompressed hard drive RAID for good sports replay.

[edDV]

I'm hoping the AVCHD doesn't suffer from the motion artifacting problems to this degree.

Untill MPeg4 hardware encoders improve dramatically, AVCHD is likely to have even lower motion performance than HDV. Maybe the Prosumer AVCHD versions will have special high bitrate "sports" modes.

There are reasons why pros shoot with highbitrate camcorders, edit at high bitrate and only then compress it down.

[DereX888]

-- and one reason I really can't stand watching 24fps film in most theaters as the pans look sick .... 24fps really sucks.

ditto

go watch live stage plays instead
If 'panning' your eyes will still have any artefacts, then you can complain to God i guess

[BJ_M]

no - i dont need to watch live stage - just the stuff we film in 70mm @ 30 - 60fps

[Specialist]

1. http://tinyurl.com/eqnzu

"Motion, especially fast-moving and detailed motion as in sports
footage, presents quite a challenge for the real-time MPEG encoders in
standard HDV cameras."

"It's a challenge HDV can often meet, but not always."

"This is the downside of HDV's impressive MPEG compression
efficiency."

2. http://tinyurl.com/h6qwu

"Shooting with the Sony HDR-FX1, we noticed that the image quality,
although generally very good, becomes a bit noisy (or blurred) when we
panned with the camera."

"Actually, this is quite typical for MPEG-2 compression, even in HD
broadcasts, as we noticed in the Summer Olympics broadcasts."

"With the HDR-FX1, the blur/noise is more visible because it features a
less expensive codec."

"Using an HD-SDI converter, we then hooked up the camera with a
portable HDCAM deck (SONY HDW-250)."

"This let us bypass the MPEG-2 codec (with a transfer rate of 25 Mbps)
and, instead, record uncompressed HD (with a rate of 140 Mbps)."

"This resulted in a higher image quality with relatively clean pans."

"Based on our experience, we also recommend minimizing horizontal
movement (panning) as much as possible in order to maintain a clean
image."

"If you need to pan (and want to maintain the image quality), always
pan as slowly as possible!"

3. http://tinyurl.com/zn7c3

John Beale -- author of the famous Web site about the old Sony
DCR-TRV900 -- now uses HDV camcorders, but when he down-converts to
standard definition, he has to apply blur filters to the down-converted
HDV to overcome unique issues (click the preceding link to read about
those).

4. http://tinyurl.com/bedru

Wikipedia:

"Compared to more expensive HDCAM and DVCPRO HD equipment, HDV suffers
from significantly more spatial and temporal (motion) artifacts."

"As a consequence of interframe (temporal) compression, HDV editing is
more complex, and introduces greater distortion at the splice point
(due to the interdependence of adjacent video frames.)"

"Compared to conventional SD DV, HDV offers a much higher spatial
resolution, so most observers are willing to accept the artifacts in
exchange for a higher-definition picture."

5. http://tinyurl.com/ehcum (by DV MAGAZINE's Adam Wilt)

"HDV looks very good for scenes of low to moderate complexity and
unhurried motion."

"But a lot of high-frequency detail and/or abrupt, complex motions
cause noticeable degradation in the form of posterization, blocking,
and pseudo-random noise."

"Unlike DV, where the most noticeable artifact is localized 'mosquito
noise' around areas of high detail, HDV's artifacts can permeate the
entire frame, and are scene dependent in their characteristics."

"Furthermore, each frame's quality varies with the complexity of the
other 14 frames in its Group of Pictures (for 1080i; 720p uses a
6-frame GOP), so there's a time dependency to HDV's artifacts that's
absent in DV."

"After a couple of months of working with the HDR-FX1, I still get
surprised at how certain scenes react to HDV's compression."

"For the most part, an HDV camera original tape played back at 1 x
speed looks quite good, with artifacts adding a feeling of overall
noise rather than appearing as noticeable, localized defects."

"However, the 'noise' buildup on busy scenes is noticeable."

(The preceding comments are from Adam Wilt and I agree with him. - JJ)

6. http://tinyurl.com/guz3s

(Excerpt from Larry Jordan's Final Cut Pro Newsletter.)

Also, a great article about how AVCHD H.264/MPEG-4 compares:

http://tinyurl.com/nvvtd

Jerry Jones
http://www.jonesgroup.net

[edDV]

Good work