| /* | |
| * Simple sound playback using ALSA API and libasound. | |
| * | |
| * Compile: | |
| * $ cc -o play sound_playback.c -lasound | |
| * | |
| * Usage: | |
| * $ ./play <sample_rate> <channels> <seconds> < <file> | |
| * | |
| * Examples: |
| frame_bytes = runtime->frame_bits >> 3; | |
| chunk_length = 4096 / frame_bytes; | |
| pcm_buffer_size = snd_pcm_lib_buffer_bytes(substream); | |
| period_elapsed = 0; | |
| audio->buffer_pos += chunk_length; | |
| if (audio->buffer_pos >= pcm_buffer_size) |
| static snd_pcm_uframes_t audio_pointer(struct snd_pcm_substream *substream) | |
| { | |
| struct audio *audio = snd_pcm_substream_chip(substream); | |
| return bytes_to_frames(substream->runtime, audio->buffer_pos); | |
| } |
| The framebuffer driver works based on page fault. | |
| When there is a page fault, it reads the modified | |
| page and send over USB. So I counted the number of | |
| page fault that occurs while playing a 7 second video | |
| file. | |
| I found that the number of page fault in beaglebone | |
| is way higher than my Ubuntu machine. | |
| Here goes the comparison: |
Order Raspberry Pi Open Box
Torrent ArchLinuxArm
wget http://downloads.raspberrypi.org/images/archlinuxarm/archlinuxarm-29-04-2012/archlinuxarm-29-04-2012.zip.torrent
open
wget http://downloads.raspberrypi.org/images/archlinuxarm/archlinuxarm-29-04-2012/archlinuxarm-29-04-2012.zip
Install
| Download Image Files: | |
| wget http://downloads.raspberrypi.org/images/archlinuxarm/archlinuxarm-29-04-2012/archlinuxarm-29-04-2012.zip | |
| Download zImage: | |
| https://www.dropbox.com/s/upvruf15j83t7a9/zImage?dl=0 | |
| QEMU Command to Run: |
| <!doctype html> | |
| <html> | |
| <head> | |
| <title>Appbase.io + Socket.io</title> | |
| <link rel="stylesheet" href="/bower_components/bootstrap/dist/css/bootstrap.min.css"> | |
| <style> | |
| #header { |
| #header { | |
| background-color:black; | |
| color:white; | |
| text-align:center; | |
| padding:5px; | |
| } | |
| #nav { | |
| line-height:30px; | |
| background-color:#eeeeee; | |
| height:300px; |
| <script src="/socket.io/socket.io.js"></script> | |
| <script> | |
| var socket = io(); | |
| </script> |
| var Appbase = require('appbase-js'); | |
| /* appname, username and password should be changed */ | |
| var appbaseRef = new Appbase({ | |
| url: 'https://scalr.api.appbase.io', | |
| appname: 'Your App Name', | |
| username: 'Your App User Name', | |
| password: 'Your App Password' | |
| }); |