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by paulslocum
Thu Oct 05, 2017 12:08 am
Forum: C/C++
Topic: SDL_Image won't display JPEGs
Replies: 11
Views: 2857

Re: SDL_Image won't display JPEGs

I was able to resolve it with by manually installing libtiff (using the command "sudo apt-get install libtiff5-dev"), and then compiling and installing SDL2_image from source code. Unfortunately this didn't work for me. I went through the process twice just to be sure and verified that I was linkin...
by paulslocum
Tue Oct 03, 2017 3:26 pm
Forum: Graphics programming
Topic: Programmatically check if MPEG2/VC1 license is unlocked?
Replies: 3
Views: 1309

Programmatically check if MPEG2/VC1 license is unlocked?

Is there any simple way to check this without actually running omxplayer?
by paulslocum
Sat Sep 30, 2017 11:55 pm
Forum: General programming discussion
Topic: Development Environment
Replies: 5
Views: 2457

Re: Development Environment

I use TextWrangler/BBEdit to edit source files directly on the Pi via SFTP, and I just SSH into the Pi and use the terminal for building and debugging. I use the Transmit FTP program to move files between my Mac and different Raspberry Pis. I've built a pretty substantial C++ project this way, about...
by paulslocum
Sat Sep 16, 2017 11:31 pm
Forum: Advanced users
Topic: Bluetooth LE advertisement timing instability / transmission delays
Replies: 9
Views: 2024

Re: Bluetooth LE advertisement timing instability / transmission delays

I was able to stabilize the timing, and I think that using averaging and noise rejection techniques similar to Network Time Protocol, it should typically be possible to synchronize RPi clocks over bluetooth to within 1 millisecond even with a lot of bluetooth or wifi traffic. There was a bug in my c...
by paulslocum
Tue Sep 12, 2017 5:48 pm
Forum: Advanced users
Topic: Bluetooth LE advertisement timing instability / transmission delays
Replies: 9
Views: 2024

Re: Bluetooth LE advertisement timing instability / transmission delays

We have a 1000 watt microwave downstairs in the room below where I'm testing, probably about 25 feet away. I tried running it while my program was running, and it did not affect it at all. I still consistently got about 10 milliseconds round trip. The only thing I've found that consistently affects ...
by paulslocum
Tue Sep 12, 2017 5:08 am
Forum: Advanced users
Topic: Bluetooth LE advertisement timing instability / transmission delays
Replies: 9
Views: 2024

Re: Bluetooth LE advertisement timing instability / transmission delays

After further testing, I suspect that you may be right about it being both bluetooth firmware/code and environmental factors. I think maybe there are two things going on here. One seems to be that heavy bluetooth LE traffic is causing collisions which are delaying the transmissions. I noticed that m...
by paulslocum
Mon Sep 11, 2017 9:24 pm
Forum: Advanced users
Topic: Bluetooth LE advertisement timing instability / transmission delays
Replies: 9
Views: 2024

Re: Bluetooth LE advertisement timing instability / transmission delays

The scale of time variance (hundred of milliseconds) does not really make sense for your suggested explanations. I can often get hours of timing responses that are within about 3 milliseconds tolerance, and then it goes into wildly inconsistent delays of sometimes even up to 1 second. The hardware c...
by paulslocum
Mon Sep 11, 2017 12:18 pm
Forum: Advanced users
Topic: Bluetooth LE advertisement timing instability / transmission delays
Replies: 9
Views: 2024

Bluetooth LE advertisement timing instability / transmission delays

I'm attempting to synchronize two Raspberry Pi's clocks over Bluetooth by repeatedly transmitting BLE advertisements containing the current time (I update the advertisement data with the time and then briefly turn on advertising to send out one advertisement). I also have the receiver generate a rep...
by paulslocum
Tue Jul 11, 2017 11:02 am
Forum: Graphics programming
Topic: Video sync loss when using SDL and two Omxplayers
Replies: 10
Views: 2392

Re: Video sync loss when using SDL and two Omxplayers

That's great, even without per-resource control it's very useful to me. Thanks for all the quick replies.
by paulslocum
Mon Jul 10, 2017 11:38 pm
Forum: Graphics programming
Topic: Video sync loss when using SDL and two Omxplayers
Replies: 10
Views: 2392

Re: Video sync loss when using SDL and two Omxplayers

It looks like my program is now working fine, but do let me know if you find out something about removing the framebuffer. One more slightly related question if you don't mind -- is there a way to scale low resolution video playback up to the screen size without blurring the pixels, using something ...
by paulslocum
Mon Jul 10, 2017 12:09 pm
Forum: Graphics programming
Topic: Video sync loss when using SDL and two Omxplayers
Replies: 10
Views: 2392

Re: Video sync loss when using SDL and two Omxplayers

Turning HDMI off and then back on doesn't seem to disable the framebuffer for me, I use those commands to turn on/off my monitor all the time from the console. If those commands disabled the framebuffer, wouldn't that be a bug? I think I read that before and assumed it must be an error or outdated. ...
by paulslocum
Mon Jul 10, 2017 1:32 am
Forum: Graphics programming
Topic: Video sync loss when using SDL and two Omxplayers
Replies: 10
Views: 2392

Re: Video sync loss when using SDL and two Omxplayers

Moving the preloading video off screen stopped the monitor from losing sync, and also appears to have reduced heat output significantly. I really appreciate the help. I looked for a way to disable the Linux framebuffer with Tvservice and could not find it. Sorry if I'm missing something obvious, but...
by paulslocum
Sun Jul 09, 2017 10:14 am
Forum: Graphics programming
Topic: Video sync loss when using SDL and two Omxplayers
Replies: 10
Views: 2392

Re: Video sync loss when using SDL and two Omxplayers

Thanks, that's very helpful. I included up to a 1s second delay between closing/launching new players to insure that there are not sometimes three players at once. Currently the issue occurs when the SDL layer fills the whole screen and both Omxplayers are displayed on top of each other in the corne...
by paulslocum
Sat Jul 08, 2017 8:23 pm
Forum: Graphics programming
Topic: Video sync loss when using SDL and two Omxplayers
Replies: 10
Views: 2392

Video sync loss when using SDL and two Omxplayers

My monitor gets brief, periodic sync loss when I'm running two concurrent instances of Omxplayer with SDL. The two Omxplayer instances are closed and reopened at regular intervals, and the dropout appears to happen intermittently when one of the Omxplayer instances is launched. I optimized my SDL co...
by paulslocum
Tue May 30, 2017 4:06 am
Forum: C/C++
Topic: C++ get input from dmx512
Replies: 1
Views: 407

Re: C++ get input from dmx512

Haven't tried it, but I bought the Velleman adapter hoping to get it working at some point:
http://www.instructables.com/id/Raspber ... ontroller/
by paulslocum
Mon May 29, 2017 1:10 pm
Forum: Graphics programming
Topic: graphics_get_display_size doesn't work
Replies: 2
Views: 1193

Re: graphics_get_display_size doesn't work

I just grab the output of "tvservice -s" to get the display resolution to use for SDL
by paulslocum
Sat May 27, 2017 4:08 am
Forum: C/C++
Topic: How to find memory leaks?
Replies: 2
Views: 658

Re: How to find memory leaks?

Thanks, got it. I had searched efence and electricfence, but didn't think to try it with a dash.
by paulslocum
Fri May 26, 2017 10:18 pm
Forum: C/C++
Topic: How to find memory leaks?
Replies: 2
Views: 658

How to find memory leaks?

Valgrind doesn't work for me and I can't figure out how to install efence. I find documentation for electric fence, but I can't find a package or source to build (only dead links). Are there any other options?
by paulslocum
Thu May 25, 2017 2:41 am
Forum: C/C++
Topic: SDL_Image won't display JPEGs
Replies: 11
Views: 2857

Re: SDL_Image won't display JPEGs

Thanks for going to the trouble of compiling it and isolating the problem. I'll look into it further...
by paulslocum
Wed May 24, 2017 11:34 pm
Forum: C/C++
Topic: SDL_Image won't display JPEGs
Replies: 11
Views: 2857

Re: SDL_Image won't display JPEGs

IMG_GetError( ) just says "JPEG loading error"
by paulslocum
Tue May 23, 2017 9:10 pm
Forum: C/C++
Topic: SDL_Image won't display JPEGs
Replies: 11
Views: 2857

SDL_Image won't display JPEGs

I'm using the following code to load and display images. This code works great with pretty much every GIF and PNG I've tried, but it doesn't work with any JPEGs --"surface" and "texture" both come back NULL. I downloaded a bunch of random JPEGs from the internet, and none of them will display. Any i...
by paulslocum
Sat May 13, 2017 8:38 pm
Forum: C/C++
Topic: Controlling OMXPlayer via dbus from c or c++
Replies: 6
Views: 1666

Re: Controlling OMXPlayer via dbus from c or c++

It's likely that the lag you're experiencing is from Omxplayer seeking and rebuffering rather than from dbus itself. You might be able to improve performance by reducing the buffer sizes. The Omxplayer main loop also has some sleep commands that may be slowing down dbus response time, or causing com...

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