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AVCHD Format Discussion
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Old April 10th, 2009, 12:18 PM   #1
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Need some advice basic confusion!

HI,
I am strictly an amateur and trying to improve my basic understanding and skills. I am seeking some resources to help broaden my basic understanding and was looking for some advice from all of you as to books and resources for more information.

I was recently listening to a podcast and the discussion was about the different formats and sizes of video recordings. The host said that one reason so many amateur products look so bad is most digital camcorders record in 1080I and the interlaced image actually degrades the look of the video.

The host recomended to record in 520P as it was essentually the same as 1080I. This made sense but I don't like just following one source so I set out to understand the modes on my camera better.

Well oh my this lead to becoming more confused, as I have read many sources of information and as I pick up bits and pieces here and there but have not been able to put it all together yet. As i learn more the more i find I don't understand ! :)

I have a CAnon HF10 I puchased last year and it can record in 1920 X 1080 or 1440 x 1080I and in 30 fps or 24fps. Using Imovie 09 or FCE i can pull this in and work with the video.

It gets a little complicated as I had a G5 mac and had to use a 3rd party program (Voltaic HD) for converting the AVCHD as the power pc would not do that natively. I have now purchased a intel mac and do not have this issue but I have quite a bit of video that is still in AVCHD format and I don't know if I have converted it to the best format as this all somewhat confuses me.

If there are any resources I could research these types of questions I would appreciate some direction. Things I am trying to determine are:

1. Best mode to record in.

2. What should I be converting the AVCHD format to for use in FCE or Imovie.

3. What are the differences in all of these formats and how to take advantage of them. 1080I, 720P 520P different frame-rates, 24, 30, 60. Oiy!

4. Should I be importing directly into FCE or Imovie now that I can or is it better to use Voltaic HD to convert first?

I hope these questions are ok to ask for being to basic.

Thanks in advance for your advice on where to learn all this great stuff!
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Old April 10th, 2009, 04:20 PM   #2
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Quote:
Originally Posted by Rick Stuve View Post
1. Best mode to record in.

2. What should I be converting the AVCHD format to for use in FCE or Imovie.

3. What are the differences in all of these formats and how to take advantage of them. 1080I, 720P 520P different frame-rates, 24, 30, 60. Oiy!

4. Should I be importing directly into FCE or Imovie now that I can or is it better to use Voltaic HD to convert first?

I hope these questions are ok to ask for being to basic.

Thanks in advance for your advice on where to learn all this great stuff!
1. Really depends on what you are doing. 24p tends to be the favorite for making a film like video. 30p is prob the norm, good for making online videos or something of the sort. 60i is good for recording action like sports... it basically means how many frames per second. if it ends in p then it is progressive, which means it's 30 full "pictures" per second if you record in 30p. and i stands for interlace which means it only records half an image for a frame. so 60i means there is 60 half frames, makes it smoother but not as clear.
ps. 1080i is visually the same of 720p not 520p. Just clear that up.

2. For avchd. Import the movies directly from the camcorder, right to iMovie or FCE. I use iMovie 09. just hit file import from camera and it will pop up. And you will be able to edit the raw files for best quality.

3. 1080i means 1920 pixels wide by 1080 pixels high recorded in interlace. 720p mean 1280 pixels wide by 720 pixels high in progressive. Never really herd of 520p. Maybe 420p which is 640 pixels wide by 480 pixels high in progressive.

4. Definitely import right into iMovie or FCE. Will give so much better quality. And make sure when you are exporting, you are using good quality.
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Old April 10th, 2009, 11:18 PM   #3
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Need some advice

Thank you for the input very much. I was also hoping for some resources that I could learn about all the issues I am questioning as well as hoping for answers.

any input as to books or other resources that could educate me in all these and other basics would be helpful and appreciated.

Thanks

Rick
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Old April 11th, 2009, 02:18 AM   #4
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It's tough getting your head round all these issues. I started with video in November 2008 and, although I know a lot about still photography, it took a long time to understand what I was doing. Apart from here (which I've found really helpful in many ways), I've found the following useful:

Simplydv.co.uk has a forum which is a bit smaller than this one, but which has less experienced pros contributing. It complements this one quite well.

This book:

Digital Camcorder Technique: Peter Wells: Amazon.co.uk: Books

was extremely helpful. Short and to the point. I also have his book on editing, which is just as good.

The worst aspect, I've found, is making sense of HD 1080 v 720, interlaced v progressive (not because it's intrinsically hard, but because there's so much 'religious' fervour around. - is Canon's 24f 'true' progressive; what is 'true' HD etc etc.-), film look and a couple of other oddities. Maybe this will help.

1. Interlaced v progressive.

Interlaced is a way of dealing with action happening faster than the camera can otherwise handle. It's not bad or good. It's just got its own characteristics. As a rule of thumb, interlaced works well for fast moving action, but at the cost of ultimate image quality. The best way to understand its effects is to shoot the same scene/type of action using an i setting and a p setting, and see how they look raw. Then decide which you like better. It'll be different for different scenes.

2. 'True' HD

It's an irrelevance. You're just shooting movies and you want them to look good. No-one (with sense) will look at them and say 'Only 1440 - not true HD, so it's a bad movie).

3. HDV vs AVCHD

If you have a computer that will hack it, doesn't matter. What matters is whether you can use the camera, and like using it.

4. Film Look

Complicated. First, video isn't film. If you want to go this way, you'll only be able to approximate. Second, film look comprises a number of factors:

- Film responds differently to light from digital sensors, and so colours etc show differently. Colour grading software can help.
- Consumer and semi-pro camcorders have sensors smaller than 35mm. It affects depth of field and focus
- Film cameras roll at 24 frames per second, which affects how motion is perceived. Video camcorders 'roll' at either 30 (NTSC) or 25 (PAL) frames per second, which are different. This is the one area where interlaced is bad. Interlaced, the frame rates are 60 and 50 respectively, which are *very* different from 24.

The thing I've learned is that there's no 'best' in any of these. You have to try stuff out, from camera setup, through editing to output, and find what works for you.
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Old April 11th, 2009, 02:02 PM   #5
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http://upload.wikimedia.org/wikipedi...lacingani2.gif
here's a little diagram kinda explaining interlace vs. progressive.

- Progressive is the first image, a full pictures
- interlaced is the 2nd and 3rd showed in a little slower piction. It puts the images back to back and tricks ur eyes to see the full image. Obviously more fluid and real with actual frame rate.
- the last is a process where they convert interlaced and convert it into progressive. it blurs it a bit but makes a full picture.
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Old April 11th, 2009, 04:07 PM   #6
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Originally Posted by Nick Gordon View Post
Simplydv.co.uk has a forum which is a bit smaller than this one, but which has less experienced pros contributing. It complements this one quite well.


Ah, the impreciseness of the English language: did you mean that the pros have less experience - or that there are less of them? :-)
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Old April 11th, 2009, 10:30 PM   #7
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Need some advice

Thank you so much for the information. Looks like its as complicated as I have been finding out. I will look into the resources suggested and appreciate any more that you offer.

Thanks again.


rick
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Old April 12th, 2009, 10:31 AM   #8
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Originally Posted by Rick Stuve View Post
Thank you so much for the information. Looks like its as complicated as I have been finding out. I will look into the resources suggested and appreciate any more that you offer.

Thanks again.


rick
Rick,

It can be complicated, but it can also be quite simple.

Video works...And your HF10 (If I got that right) quite simply, works quite well. You got some good advice on how to get it into your computer and I would just start doing it and get familiar with how your software works in editing.

I'm in the PC arena, work with HF100's (same as the HF10 but without the internal memory) and most of the time I just use the default 60i frame rate. I do like a bit of the "film" look so I use the Cine mode almost exclusively. Cine mode by itself can look very flat (the muted color and contrast gives better dynamic range and gets away from the pure bright "video" look) so I go into "custom presets" and boost the contrast, brightness, and sharpness a tad. This gets away from the "flat" look but still takes advantage of Cine modes expanded dynamic range.

The 30p and 24p are still in a 60i "wrapper", I don't chase the film 24 frames per second flicker "will -o the wisp" so I never use 24p. 30p has a strange side effect on this camera. Because it is not recorded in true 30p but is still captured in cam as 60i (2 half frames) it appears extra time is needed to blend the 2 interlaced fields into one progessive frame before recording to media. The result is a slight "lag" on both the LCD image and the audio (you encounter this audio lag only if monitoring with headphones).

In default modes you move the camera and the LCD image follows immediately with no delay, in 24p and 30p modes move the camera and the LCD image follows only after a very slight delay. You can still do pans to follow action but it is disconcerting if you don't know to expect it.

But just take that HF10 and start using it. The results are usually both fun and gratifying.
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Old April 15th, 2009, 05:22 AM   #9
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Originally Posted by Robin Davies-Rollinson View Post
Ah, the impreciseness of the English language: did you mean that the pros have less experience - or that there are less of them? :-)
Curses! I pride myself on being unambiguous, dammit!.

I meant that there less of them. They might be less experienced too, but I have insufficient data to say so.
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Old April 15th, 2009, 06:06 AM   #10
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Film running at 24fps and interlaced video are both products of economics. Film speed of 24fps was a compromise between the amount of film that would be need to get copied and distributed to cinemas and the quality of motion and optical sound on the film.
Interlace video was devised to get the smoothest motion possible using the least transmission bandwidth. Interlace video was designed as a system including the display--the CRT. The camera views the image ( in NTSC) 60 times a second but only sends the odd or even horizontal lines each 1/60 of a second. So the temporal motion is 60fps but only half the vertical resolution information is sent. It is the CRT that completes the picture using the decay time of the phosphors. They don't switch on and off like on LCD but decay slowly. This blending of the fields works with our eyes and brain to convince us that the image is complete and moving at a smooth 60fps whereas in fact only fields change every 1/60 second. The effect only works if viewed far enough away from a CRT so that the horizontal scan lines cannot be seen easily. Hence the recommended viewing distance for CRT.
The problem has now come in that LCD or Plasma displays are progressive at 60hz (for NTSC in N.A.) These displays must now use the interlace input to create a progressive image for display. Some do this well, lots do this badly and display interlace artifacts ( jagged edges etc).
Convention says NTSC is 30fps because 60 fields=30frames unfortunately these fields can't just be added together because they were captured by the camera 1/60sec apart.
Ideally 60fps progressive would be nice as it would retain the smooth motion of 60i in a full progressive form. Unfortunately this is technically difficult and is only just becoming possible on an economic basis so isn't actually included in the FUll HD spec( ie 1920x1080P60) 1280x720P60 is available is included in spec and is used by lots of networks.
The numbers change to 50 for PAL but essentially the same approach.

Ron Evans
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