feat: generalise spec and ready release

.gitignore

@@ -5,3 +5,4 @@
 *.dwarf
 captured_frame.png
 shard.lock
+test.mp4

shard.yml

@@ -1,5 +1,5 @@
 name: v4l2
-version: 0.1.0
+version: 1.0.0
 
 development_dependencies:
   ameba:

spec/spec_helper.cr

@@ -4,13 +4,39 @@ require "ffmpeg"
 require "stumpy_png"
 require "../src/v4l2"
 
-unless File.exists? "./test.mp4"
+# the video file we'll use for testing
+video_file = "./test.mp4"
+unless File.exists? video_file
   puts "downloading video file..."
   HTTP::Client.get("https://test-videos.co.uk/vids/bigbuckbunny/mp4/h264/360/Big_Buck_Bunny_360_10s_5MB.mp4") do |response|
     raise "could not found video file" unless response.success?
-    File.write("./test.mp4", response.body_io)
+    File.write(video_file, response.body_io)
   end
 end
 
-loopback_device = V4L2::Video.find_loopback_device
-raise "no available loopback device" unless loopback_device
+# ensure we have a loopback device
+loopback = V4L2::Video.find_loopback_device
+raise "no loopback running. run 'sudo modprobe v4l2loopback'" unless loopback
+LOOPBACK_DEVICE = V4L2::Video.find_loopback_device.as(Path)
+
+# push a video to the loopback device for
+wait_running = Channel(Process).new
+spawn do
+  Process.run("ffmpeg", {
+    "-stream_loop", "-1", "-re", "-i", video_file,
+    "-f", "v4l2", "-vcodec", "rawvideo",
+    "-pix_fmt", "yuyv422", LOOPBACK_DEVICE.to_s,
+  }) do |process|
+    wait_running.send process
+  end
+end
+
+# terminate ffmpeg once the spec has finished
+select
+when process = wait_running.receive
+  # ensure the process exits once the spec has run
+  Spec.after_suite { process.terminate }
+  sleep 1
+when timeout(5.seconds)
+  raise "timeout waiting for ffmpeg to launch"
+end

spec/v4l2_spec.cr

@@ -2,36 +2,39 @@ require "./spec_helper"
 
 module V4L2
   describe V4L2 do
-    it "loads the library and runs some functions" do
-      LibV4l2::CreateBuffers.new
-      vid = Video.new(Path["/dev/video0"])
-      pixels = vid.supported_formats
-      pixels.each(&.frame_sizes.each(&.frame_rate))
-      pp! pixels
+    it "can inspect the device name" do
+      vid = Video.new(LOOPBACK_DEVICE)
+      details = vid.device_details
+      (details.name.size > 0).should be_true
+      details.name.should eq "Dummy video device (0x0000)"
+    end
+
+    it "can inspect the stream details" do
+      vid = Video.new(LOOPBACK_DEVICE)
+      format = vid.supported_formats[0]
+      format.code.should eq "YUYV"
+      format.description.should eq "YUYV 4:2:2"
+      size = format.frame_sizes[0]
+      size.width.should eq 640
+      size.height.should eq 360
+      size.frame_rate.fps.should eq 30
     end
 
     it "resets the buffer properly" do
-      vid = Video.new(Path["/dev/video0"])
+      vid = Video.new(LOOPBACK_DEVICE)
       vid.buffer.index = 3_u32
       vid.buffer.index.should eq 3_u32
       vid.reset_buffer
       vid.buffer.index.should eq 0_u32
     end
 
-    it "gets the device name" do
-      vid = Video.new(Path["/dev/video0"])
-      details = vid.device_details
-      (details.name.size > 0).should be_true
-    end
-
     it "can stream and scale" do
-      vid = Video.new(Path["/dev/video0"])
+      vid = Video.new(LOOPBACK_DEVICE)
       pixels = vid.supported_formats
-      pixels.each(&.frame_sizes.each(&.frame_rate))
 
-      # highest resolution + framerate combo
-      format = pixels[1].frame_sizes[1].frame_rate
-      vid.set_format(format).request_buffers(1)
+      # grab the first available
+      format = pixels[0].frame_sizes[0].frame_rate
+      vid.set_format(format).request_buffers(2)
 
       # setup the ffmpeg image format conversion
       # v4l2_frame = FFmpeg::Frame.new(format.width, format.height, :yuyv422)
@@ -56,7 +59,7 @@ module V4L2
         convert.scale(v4l2_frame, rgb_frame)
       end
 
-      (count > 0).should eq true
+      (count > 1).should eq true
 
       # save the last frame using stumpy png
       pixel_components = format.width * format.height * 3
@@ -72,6 +75,8 @@ module V4L2
         canvas.pixels[index] = StumpyCore::RGBA.new(r, g, b)
       end
       StumpyPNG.write(canvas, "./captured_frame.png")
+
+      File.exists?("./captured_frame.png").should eq true
     end
   end
 end

src/v4l2/video.cr

@@ -190,12 +190,13 @@ class V4L2::Video
     close
   end
 
-  def self.find_loopback_device : String?
+  def self.find_loopback_device : Path?
     Dir.glob("/dev/video*").each do |dev_path|
       begin
-        video = V4L2::Video.new(dev_path)
+        path = Path[dev_path]
+        video = V4L2::Video.new(path)
         begin
-          return dev_path if video.device_details.card.downcase.includes?("dummy")
+          return path if video.device_details.card.downcase.includes?("dummy")
         ensure
           video.close
         end