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 Topic: Apple Video Player not recording... (Page 1 of 1)
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  TheEisenfaust (Profile)
  8 MB
 
Posted: Sat Jun 21, 2014 3:56 am
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Ok folks, here's my stats:
Power Macintosh 6500/225
Sonnet Crescendo L2/G3 400MHz/512K Processor Upgrade card
128 MB RAM
15GB HDD
Apple TV/Video System (TV Tuner and AV in cards)
Macintosh System 7.6.1

Here's my issue:
I've been using this machine as my retro videogaming machine as my new TV that replaced my old one unfortunately does not have Composite In, only HDMI. It runs input on all my retro consoles just fine with no issue whatsoever. I recently decided that I wanted to record gameplay footage on the machine so that I can upload my speed-run footage on YouTube. When I start to record it works for about 15-20 seconds, then the whole computer locks up and the only thing that moves on the screen is from the AV or TV Tuner cards. This happens not only with Apple Video Player, but with the included Avid VideoShop 3.0 software. A friend of mine seems to think that it might be my G3 Upgrade card causing interference, but I wanted to get a second opinion before I pulled it out and put back in the old L2 Cache card. Any thoughts?
  
  TheEisenfaust (Profile)
  8 MB
 
Posted: Wed Jun 25, 2014 10:15 pm
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Update: I swapped in the old L2 Cache card and it still crashes when I try to record video... Now I'm completely at a loss on what to do to fix this issue. Any ideas?
  
  wove (Profile)
  Moderator
 
Posted: Thu Jun 26, 2014 8:10 am
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The Apple TV-Video system is a nicely designed system. Video is captured by the card, broken into necessary pieces and sent directly to the computers video subsystem where it is displayed. Apple designed the card primarily for viewing video on screen. This works reliably for viewing on very low powered systems.

But capturing that stream to the disk is much more resource intensive than just viewing. The capture process involves two steps. The raw data from the video subsystem is moved over the system bus to the drive bus where it is then written to disk. After the raw stream has been captured the system goes back through this raw data dump and turns in into a playable movie.

You can figure the amount of data that needs to be captured from the window size the frame rate and the color depth. The system specs will tell you the buss speed, its data width, and the write speed of the drive controller and the drive. So the first thing is to make sure you are not trying to capture more data than the system can handle. You are going to find that the system is capable of displaying bigger windows and more color than it is capable of capturing. On most older systems you are not able to successfully capture anything but the most minimal of video that the player can display.

At the raw capture phase the speed of the processor is immaterial to the operation. What counts for the initial capture is keeping the bus free. You want to boot the system with every extension and control panel off except for those necessary for the video. The entire system bus needs to be dedicated to video data for the entire length of the capture. Any interruption however slight will cause failure. So there can be no checking on network activity, no playing on the keyboard, etc.

The drive of course is also involved in this process and it is often the weak link. You should have a drive with good specs, it needs lots of free space and it should not be fragmented. Fragmenting does not impact the Mac OSís operation, but it does impact a driveís write speed.

After you have stopped recording the software will go back and sort through the raw data that has been captured, compress the data and store it as a movie file. This step is very processor intensive and will take substantially more time than it took to capture the data. However this step is done in software and is not as critical or prone to failure. Failure during this step is primarily because of operator impatience.

So success in creating a movie using the Apple TV/Video system requires keeping the amount of data captured within the specs of the machineís capabilities, making sure there are no interruptions from background processes, insuring a sufficiently sized drive is operating with good efficiency, and patience while the system processes the data after it has been captured.

bill
  
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