Waterfall/moving water correction?
 

Topic:Waterfalls, gushing streams and other forms of moving water.

This past weekend I took a brief trip to New Hampshire's White Mountains. I took some footage of the Crystal Cascades which is beautiful and majestic to behold in this part of the world. HDV 1080 60i . This was my initial foray into nature with my Canon A1s.

I have very little experience in shooting this type of content and plan to shoot more like it just as soon as possible in that region. I need to learn how to maximize results and output.

Upon viewing, import and playback, I quickly noticed the following:

Granted the water was chaotic in places, flowing at a high rate and somewhat torrential however I saw jagged and sharp lines jumping all over the place which significantly impacted on the quality.

Bottom line: it looked a touch ragged and my goal is to have the footage be more orderly and smoother.

Is what I'm seeing interlacing or another type of problem?

Is there possibly a camera setting that would improve things next time out?

How do I successfully address the above and correct this to the extent possible?

Thank you.

Re: Waterfall/moving water correction?
 

Those sound like compression artifacts. Compressed video has one main enemy: complexity. If a moving image is highly complex, constantly changing and in motion, an HDV camera has a hard time recording it. Unfortunately, what you shot is what you got...so it wouldn't be possible to fix such a scene in post. HDV has a 4:2:0 colorspace. Perhaps if you tried a camera with 4:2:2 colorspace, and a codec with lower compression, you could capture this image cleanly.

Re: Waterfall/moving water correction?
 

Do I have more hope for a better result if I use a AVCHD camcorder instead?

Thanks for responding.

Re: Waterfall/moving water correction?
 

Bruce,
From my experience it sounds like interlaced footage is causing the issue. I did a project for DVD on waterfalls which was shot in interlace DVCPRO100 since the DVD format is interlaced. On a computer, playback was a little ragged with horizontal scan lines in the water.

Encoded for DVD via TMPge4 and played back on a stand alone DVD player and HDTV most of the interlaced issues became minor. If you intend to shoot moving water scenes for the web, I suggest shooting progressive at 60p and editing on a 30p timeline. This will give you the option of slowing down the 60p clips to get more detail with less chaos.

You can see a lot of fast water scenes at Natureflixs on Vimeo All the vids since "Cloudland Canyon" were shot 720 60p. All the vids before then were shot interlaced and then deinterlaced for the web. They are not quite as sharp as the true progressive ones.

If you can only shoot interlaced then use some software that does high quality deinterlacing and that might solve your problem. Here is a good article which shows interlaced vs. deinterlaced examples http://worldkayakblogs.com/videoanim...interlacing-2/

Re: Waterfall/moving water correction?
 

What does your footage look like when you hook up the camera to a tv?
Footage for the web or pc should always be deinterlaced.
For dvd shown on tv interlaced should be fine.

Re: Waterfall/moving water correction?
 

Hi Bruce,

It's the nature of HDV. Consider that DV, that came out in the late 90s, is 720x480 and is compressed to 25Mbps. Now HDV is taking 1440x1080 video - about 5x the information - and cramming it into the SAME 25Mbps stream. Something has to give.

MPEG-2 itself is not a bad codec - give it a high enough data rate, and it looks great! The problem with HDV is the combination of low data rate and "Long-GOP" recording. Only 2 complete frames are recorded each second, and the remaining frames only contain partial data, reflecting the "changes" taking place from one frame to the next. To decode the incomplete frames, the decompressor has to look forward and backward at surrounding frames to reconstruct a full frame for playback. This is why dropouts (glitches) on HDV tapes are always 15 frames minimum - one bad frame takes all its neighbors with it, unlike the intra-frame DV codec that could survive one bad frame with minimal damage.

HDV works pretty well when shooting static scenes from a tripod (think wedding ceremony), but when shooting a waterfall or a fountain, EVERY PIXEL is changing in EVERY FRAME - the codec self-destructs. Examining the footage frame-by-frame will show that it is very "blocky", as I've seen when shooting a fountain in HDV.

You could perhaps try increasing the shutter speed to eliminate some of the motion blur and maybe get a sharper image that way, but that will change the "look" of the video, and aesthetics come into play.

Since the HDV codec is the root of the issue, the answer is to use a different codec. You have the choice of going to a different camera, most of which use the more efficient H.264 codec (AVHCD), which is typically 24Mbps yet provides better quality than MPEG-2.

Best results with any of these cameras can be obtained by bypassing the camera codec altogether! A couple of options would be the BlackMagic HyperDeck Shuttle, or the Atomos Ninja portable recorders. These will take the HDMI video out from the camera (unless it is an early model lacking HDMI) straight from the sensor, BEFORE the camera adds compression. Shuttle records uncompressed 10-bit 4:2:2 video direct to SSD drives, while Ninja records to SSD or (cheap) laptop drives using the Apple ProRes codec, also 10-bit 4:2:2.

These devices breathe new life into older cameras, allowing them to capture video far superior to what they could record internally. They work just as well with any new video camera with HDMI out. I've used the Ninja to shoot dance recitals and stage plays with an HDV camera and got great results. I appreciate the uninterrupted recording of Ninja on the 2.5-hour recitals, which offered no pause for HDV tape changes!

Jeff Pulera
Safe Harbor Computers

Re: Waterfall/moving water correction?
 

Kevin: Unfortunately my choices for a camera are limited. A far as better cams goes, I own an A1s and also have access to a XH- A1 and a VIXIA HFS-20 (AVCHD) through my local cable station as I am pretty much on my own. Those that I work with at church only have GL-2's to work with some of which are mine. I'd love to have an XF-305 or something equivalent.

Would AVCHD potentially yield better results?

Mark: viewed some of you work which was well composed and shot. Thanks for the link. I fully agree it's most probably an interlace issue. Regrettably, I do not have anything that shoots in 60p, only 60i and "30 and 24F". You mentioned interlacing with software. What personally do you use or would utilize if you were in my shoes? What options does Premiere Pro have in that particular regard and is it effective? Doesn't de-interlacing soften, lessen the clarity of and degrade both the sharpness and level of detail?
Please, would you mind spelling out some of the options?

Ann: I have yet to see what it looks like on HDTV and not the PC. Thanks for the suggestion. I noticed that the closer to the falls I shot, the more "garbage" the footage contained.

Jeff: Nice to hear from you again. An aside, I have yet to get HC Encoder to accept AviSynth scripts yet and plan to call you soon. Yes, I'm with you changing that HDV tapes on the fly is a nuisance and length is limiting.

On most occasions, since I shoot church services and shuttle between 2 cameras (one of which is mostly stationary), I'm moving all over the sanctuary very quickly with a camera/pod in my hands in order to be at the right place at the same time until time for the sermon. A portable recorder or a laptop connection may not be appropriate given the above. I would need to film staying put. If the Canon A1s has HDMI out, please let me know and am sorry for my ignorance concerning that.

Just out of curiosity, how much of an investment are we talking about for the devices discussed?

Re: Waterfall/moving water correction?
 

Thanks for the post, Jeff.

Re: Waterfall/moving water correction?
 

Well i have a A1 (without the s) and a couple of years ago i filmed at Iguacu Brazil (and that is what you call a waterfall) and the footage looks great from a BluRaydisk on my hdtv.
I have my camera always set to manual. As i am in pal-land framerate is set to 50. Using the ND filter to get exposure around 4 and 5.6. Gain is set to -3 and no custom preset.

Re: Waterfall/moving water correction?
 

Kevin: Unfortunately my choices for a camera are limited. A far as better cams goes, I own an A1s and also have access to a XH- A1 and a VIXIA HFS-20 (AVCHD) through my local cable station as I am pretty much on my own. Those that I work with at church only have GL-2's to work with some of which are mine. I'd love to have an XF-305 or something equivalent.

Would AVCHD potentially yield better results?

Mark: viewed some of you work which was well composed and shot. Thanks for the link. I fully agree it's most probably an interlace issue. Regrettably, I do not have anything that shoots in 60p, only 60i and "30 and 24F". You mentioned interlacing with software. What personally do you use or would utilize if you were in my shoes? What options does Premiere Pro have in that particular regard and is it effective? Doesn't de-interlacing soften, lessen the clarity of and degrade both the sharpness and level of detail?
Please, would you mind spelling out some of the options?

Ann: I have yet to see what it looks like on HDTV and not the PC. Thanks for the suggestion. I noticed that the closer to the falls I shot, the more "garbage" the footage contained.

Jeff: Nice to hear from you again. An aside, I have yet to get HC Encoder to accept AviSynth scripts yet and plan to call you soon. Yes, I'm with you changing that HDV tapes on the fly is a nuisance and length is limiting.

On most occasions, since I shoot church services and shuttle between 2 cameras (one of which is mostly stationary), I'm moving all over the sanctuary very quickly with a camera/pod in my hands in order to be at the right place at the same time until time for the sermon. A portable recorder or a laptop connection probably not be appropriate given the above as I'm mobile while filming. I would need to film staying put in order to utilize either device properly. If the Canon A1s has HDMI out, please let me know and if so I'am sorry for my ignorance concerning that.

Just out of curiosity, how much of an investment are we talking about for the devices discussed? What's a reasonable size, cost and reliable brand for an SSD drive?

Re: Waterfall/moving water correction?
 

Hi Bruce,

Surprisingly, not seeing an HDMI out on the XH A1S - XH A1S High Definition Camcorder :: Inputs and Outputs

Therefore, eliminates using the external recorders with HDMI inputs.

Jeff

Re: Waterfall/moving water correction?
 

Bruce,

I use Edius and not Premiere Pro, but when you export your time line for the web or DVD look at the settings and I am sure there is a deinterlace function. Also, keep your bitrate high. Try that and I bet your video looks better when viewed on a computer.