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May 2nd, 2007, 07:37 PM | #16 |
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Because 24p is recorded on 60i stream with 3:2 pulldown with interlaced artifacts. Pal cam with 25p doesn't suffer from this as the native steam, 50i, is double of 25.
http://en.wikipedia.org/wiki/Telecine#3:2_pulldown Or did I get this all wrong? |
May 5th, 2007, 10:32 AM | #17 |
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The HV20 has a true progressive sensor cam. Just like the Sony V1 it records its 24p frames inside a 60i wrapper. Its 60i mode is derived from the progressive sensor and recorded as interlaced. This is the opposite of Canons other cams XLH1/XLA1 that have a native interlaced sensor and through some processing converted the stream to 24F and 30F modes.
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May 5th, 2007, 11:09 AM | #18 |
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There was an example of 24p video in the Canon HV10 / HV20 HDV Camcorders forums that showed unpleasant artifact as a result of 3:2 pulldown. Vegas can't remove them and you need to use other SW to remove these interlaced artifacts.
Here people refer to what I have mentioned: http://www.dvinfo.net/conf/showpost....8&postcount=15 http://www.dvinfo.net/conf/showthrea...&highlight=24p So the only quality and affordable cam with a true progressive video out of the box is Canon HV20 - PAL version. |
May 5th, 2007, 02:30 PM | #19 |
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I didn't see anything in those threads that mentioned any visual problems associated with the 24p. The fact is a proper NLE will remove the pull down on injest and you will be left with pure 24p in your timeline. No interlaced artifacts. No problems. The funny thing is I have heard of Vegas having some difficulty with this and their V1 uses the same 24p in 60i stream as the HV10. You might want to post a specific question in the editing forum on 24p from 60i. But as far as I know, there are no problems at all.
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May 5th, 2007, 03:37 PM | #20 |
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There is no issue with 24p as long as you do inverse telecine on the captured video and that is the trouble the HV20 owners go through (those who noticed it ;-) ).
Simply the HV20's 24p stream doesn't set some flag for vegas to recognize this stream. The fact that you can't play 24p progressively once transferred to PC seems like a big disadvantage of NTSC HV20. Discussion about vegas not being able to "deinterlace" HV20 24p stream: http://www.dvinfo.net/conf/showthread.php?t=93146 The video looks like this: http://upload.wikimedia.org/wikipedi...elecine%29.png 1st frame is progressive 2nd frame is progressive 3rd frame in interlaced 3rd frame in interlaced 5st frame is progressive It seems that many do not realize all this... |
May 5th, 2007, 04:10 PM | #21 |
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I believe most people on this site do recognize this. It's just a flag issue. From what I understand the HV20 is no different than a DVX in how it carries its picture (other than its HD and not DV). It's just that Canon seemed to have made a glitch in not using flags (which they seem to have left the option open because it is possible to do a firmware update on these cams). The HV20 is a true progressive scan cam. Yes it might be a disadvantage at the moment...but this 60i wrapper i believe is done because of NTSC standards (not sure).
Edit: but using this wrapper does not mean it does not have "truly" progressive sensors. |
May 6th, 2007, 12:35 AM | #22 |
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Peter, your first link again refers to Vegas, and as I stated there apparently is a limitation in that software. Not a limitation of the cam. As far as your second link, it appears to be related to an original interlaced source which the HV20 is not. The cam is not producing an interlaced frame but a true progressive frame directly a result of its progressive CMOS sensor. Proper software would simply remove the pull down and you would have 24p of pristine frames to edit as I stated before. Well if your software supports it that is.
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May 6th, 2007, 07:15 AM | #23 |
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Ken,
HV20 faces the same task as when transferring motion picture film into electronic form. In both cases, HV20 and motion picture, the source are progressive frames. The tasks is to transfer these frames into a device or medium. In both cases the native recoding format is interlaced hence the progressive frames must be encoded somehow to fit into these interlaced frames. Also there is a "Frame rate differences" issue. While with 24p the full frame rate is 24 frames per second with the recording device or medium the frame rate is 60i (30 full frame per second). So for every second you need 6 new frames. In other words for every 4 24p frames you need 5 frames to be encoded into 60i medium or device. As mentioned in Wikipedia: These four frames are “stretched” into five by exploiting the interlaced nature of NTSC video. This process is called "3:2 pulldown". The result is a mix of progressive and like interlaced fames. This is still better than native interlaced video but far cry from progressive. You can't play such video on your computer, progressive screen or interlaced screen and call it progressive unless these can do reverse 3:2 pulldown. This issue needs to be fixed so NLE recognize such format. Also we need a media player which would do reverse 3:2 pulldown for PC and also firmware upgrade for all those TV screens (probably not going to happen). In the mean time NTSC HV20 can't for my purpose replace HD10 but PAL version ov HV20 can. This cam is a consumer cam and consumers can't play the advertised 24p format correctly. Why this is one heck of a cam I can't help it but to criticize Canon for this issue. For me all I would need is a free media player for PC and NLE will be fixed one day in this century. http://en.wikipedia.org/wiki/Telecine |
May 6th, 2007, 01:37 PM | #24 |
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So it is simply a matter of having supported software. I would believe the Cineform software should handle the format. It has supported the V1's modes from day one.
http://www.cineform.com/products/Asp...t.htm#Features It lists telecine removal (24p from 60i) as a standard feature. I have only ever edited HDV with AspectHD, and know that they always support every HDV format from every cam correctly. I didn't realize there was such issues with other software. I don't understand how Vegas doesn't have this feature as their V1 uses the exact same mode as the HV20. As far as media players I would again make the assumption that VLC VideoLan player would handle the files correctly. Does it?
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