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What surprises me the most is the cost. I don't know much about ARM11 but by the sounds of it this little thing can do a lot. I know that ARM is used in a lot of consumer products and phones, and smart phones are getting pretty powerful. So all that on a little board thats 25 bucks? Thats a great price for a learning tool. Look at this FPGA board that one class (really just a lab) requires: 100 bucks in the bookstore, 80 online (really 50 if you use your school email). All that does is simulate gates, yet the raspberry does so much more and is cheaper? I want to get my hands on one and think its a great idea. Edit: Also I kind of think that having not much resources on the board is a good idea. I've never agreed with the whole "memory is cheap" way of teaching in CS classes. So having to learn to program within a limit may teach more proficient coding. I remember doom running well on a 486, yet some games come out today and run like poo poo on i7s with gtx 570s (CLOD). SPACE HOMOS fucked around with this message at 04:25 on Feb 25, 2012 |
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Feb 25, 2012 04:15
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A while ago I had found an old CCTV camera in a box of junk and was curious to see if it worked. As the output was NTSC via BNC conector, I just bought a cheap BNC-to-RCA adatper and a startech USB RCA input. To my surprise it the camera worked pretty well, even though the quality is what you'd expect an old sercutiy camera with a 1/3 in sensor. This lead me to want to be able to stream random crap but not be tied to my computer or the camera just being hooked up to a TV. So I bought a raspberry pi and a capture card specifically for the pi. There are some issues, but I wanted to post my findings as searching for how to properly configure everything lead to out of date information. Panasonic WV-CP244 Raspberry 3 Model A Lintest PiCapture SD1 The picapture card connects to the pi's camera port to take advantage of the native h264 encoding. This leads to an issue with NTSC input as the camera modes are made for the modern ATSC standard. So, the the image gets scaled horizontally and then cropped vertically. While NTSC doesn't exactly display the entire frame as some lines are used for additional information, such as closed captioning, it is still noticably cropped. On top of that the scaler tends to make it a little muddier as opposed to connecting it to my PC. When I first started attempting to stream video it was delayed and had tons of re-encoding issues leading to a terrible image. On top of that it was running the processor at 95%. I have to use raspivid to grab video from the camera port and force mode 6 (640x480) to correctly display the camera's output. Then pipe that to vlc, ffmpeg, etc. Originally, I was doing something like, raspivid -md 6 ... - o - | ffmpeg -i - ... -f flv "rtmp://" But this lead to terrible performance so I searched for alternatives. I tried v4l2 but I don't think there is an equivalent "mode 6" that raspivid uses; leading to an image of all noise. After wasting a lot of time I started to realize I was looking at post from as early as 2013. A lot of features such as v4l2 and ffmpeg with mmal_h264 support are already supplied in the latest raspbian stretch. Using, raspivid -md 6 ... -o - | ffmpeg -c:v mmal_h264 -i - ... -c:v copy -f flv "rtmp://" Its a lot faster, although still delayed, and it only puts the processor at 2% load. I do have an issue with time stamps as the h264 bit stream has no meta data and flv requires timestamps. This leads to some issues with streaming to twitch where the stream will get error code 5000. I've tried a couple things but haven't gotten past the issue.
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Jan 8, 2019 18:22
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