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Latest blog entry: My 2012 FPV year in Review
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JXD318 max resolution is 720x480.
Detailed Review at MP4Nation. http://www.mp4nation.net/forum/viewt...p?f=17&t=13864 Doubt recording past 640x480 is even possible with a composite cable. Also not clear if you can Record and View at the same time through goggles may require splitter.
FOUND VIDEO FOOTAGE OF JXD318 in action. |
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Biggest problem with that recorder is that it appears to max out at 25fps
according to that review. That is not enough for high motion FPV. As for recording at 720x480. It's the native resolution of DVD. Analog video sources by definition, have no set number of horizontal pixels. They have a set number of horizontal lines, but each line is showing a truly analog signal so when you convert the analog signal to digital you can choose to split it up into 320, 640 or 720 or any other number you want, horizontal pixels. If you can capture 720 pixels then you're recording a little bit more information per line. The problem is, computers generally render video with a 1 to 1 pixel aspect ratio and while the input image be 4:3 aspect ratio, which matches 640x480 resolution, when capturing at 720x480 and played with 1 to 1 pixel ratio produces a horizontally stretched image. The Aiptek MPVR+CB can choose between 720x480 and 640x480 as well. What I found is that 720x480 appears to be its native resolution so it looks best at that resolution, but when you rescale it to 640x480 in post processing to fix the aspect ratio, it looks about the same as it would captured directly at 640x480 so there's little gain from using the higher res. If you look at these two high motion clips captured off a DVD player to my Aiptek MPVR+CB a couple years ago you can see the difference. (download originals to see raw capture asf files, and play with VLC player) 640x480@30fps
720x480@30fps
I chose a clip that would sort of simulate low flying FPV. Some things to notice. The 640x480 capture ended up using about 3Mbit/s. The 720x480 capture uses about 4Mbit/s and the original looks decent. That said, any true recording of FPV flight, especially at low levels or in less than perfectly still air, will require a lot higher bitrate than either of these samples to look good. TV shows and movies are obviously filmed with very stable camera platforms and even "high motion" clips on TV are actually usually using a fixed camera position with motion moving through it, minimal panning, which allow for much higher quality at lower bitrates. That's why many DVRs designed specifically for recording TV shows can get away with low bitrates. ian |
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Latest blog entry: My 2012 FPV year in Review
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Yes it has a separate A/V output and I believe others have
confirmed that it'll output a time base corrected signal even if the input goes to static. The problem is, like most recorders that have an A/V output the video quality is not as good as the original and it includes various clutter on the screen telling you record time and so forth. Note that not all recorders that have a live A/V out while recording do time base correction. Some pass the signal through pretty much unmollested (except for the recording time overlay) and your goggles or LCD TV still won't be happy. It's best just to choose displays that don't do that, unless you want to invest in a standalone time base corrector, which are generally not cheap. ian |
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Latest blog entry: My 2012 FPV year in Review
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Melbourne, Australia
Joined Jan 2008
947 Posts
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Question for Daemon.
Hi Daemon, what is your opionion of this recorder http://cgi.ebay.com.au/2-5-HDD-AV-Vi...item4a9ca97b31 as compared to the older model (BR3002 DVR I think you called it) and the CS-T60C? I have a BR3002 DVR recording in PAL mode from a SN777 and I'm looking for something that will record in slightly higher quality. I was thinking that a higher resolution would help to achieve that but I read your post #50 and now I'm confused as to weather its worth it. What do you use (if anything) that records at 30fps? Do you record in NTSC sacrificing quality for framerate? Thanks Geoff |
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Everything I use records at 30fps. I wouldn't use anything that didn't
as I feel it is the minimum for high motion. I use NTSC because all video equipment in the US is NTSC. Having not used that recorder, I can only say that the fact that it has no buttons on it to start/stop recording would be very annoying to me. I can't speak to its recording quality. One of the features I like the most about the BR3002 is that it has dedicated buttons to start and stop recorder so I can literally operate it without looking and always know exactly what it's doing. ian |
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Latest blog entry: My 2012 FPV year in Review
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Ireland
Joined Apr 2001
3,953 Posts
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i ordered that one form those guys
hi
i ordered that one to see if it meets my requirements. For now i would hold off buying it since they did not suply me with a tracking number that shows up on the hk post or local irish post website. This does not mean it has not been send out but il have to wait and see. Once (if) I recieve it il update [QUOTE=garris2;13707541]Question for Daemon. Hi Daemon, what is your opionion of this recorder http://cgi.ebay.com.au/2-5-HDD-AV-Vi...item4a9ca97b31 |
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Melbourne, Australia
Joined Jan 2008
947 Posts
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Thanks for the reply Daemon, you've just pointed out something that is so obvious that I didn't even notice it. I had assumed the r9ound silver button in the middle duobled as the record button but in all likelyhood it does nothing else except power. Bugger.
Is there anything that records in the higher resolution of PAL and at 30fps at the same time? Geoff |
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It doesn't exist. There is no version of PAL with 625 lines running at greater than 25fps.
See the wiki articles on PAL and NTSC to see the differences. ian |
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Latest blog entry: My 2012 FPV year in Review
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updated 1st post with:
eBay 720x480 KeyChain Cameras Video Codec: Motion JPEG (720x480, 30/fps, 10263kbps) Audio Codec: PCM Audio 2050Hz 353 kb/s (1 chnl) These KeyChain cameras are an EXCELLENT choice for easy mounting/taping onto your plan, helli, or park Flyer! They Support 1-8g Micro SD chips and can record your entire flight in glorious 720x480 @30fps! The benefits of having one of these in aadition to your existing Video TX is you will have static free recording of your flight. As some of us have discovered, if you loose signal, these also also make great crash videos. |
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shawnee, ks
Joined Apr 2004
896 Posts
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Quote:
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