IEnumerator CaptureWebcamToFileCoroutine()
{
// Open a webcam streamer. The url prefix for this is webcam://
// Optionally a webcam device id can be added (to get a list, use WebCamTexture.devices)
string webcamStreamUrl = "webcam://";
Streamer streamer = Streamer.forUrl (webcamStreamUrl);
streamer.Connect (webcamStreamUrl);
// Set up a remux @ 15fps
var vi = new VideoStreamInfo (streamer.videoStreamInfo);
vi.framerate = 15; // must be lower than framerate with this approach!
AviRemux remux = new AviRemux ();
remux.Init (File.OpenWrite (outfile), vi, null);
// Do fixed time capture, 10 seconds (150 frames @ 15fps)
// The webcam framerate can be lower or higher than this. If it is lower then
// a frame is written multiple times, if higher, then some frames are now written.
float captureStartTime = Time.realtimeSinceStartup;
int realFrameNr, lastRealFrameNr = -1;
do {
// Read a frame from webcam. It returns a frame number, but we're not using it.
byte[] buf;
frame = streamer.VideoPosition;
int bytesCnt = streamer.ReadVideoFrame (out buf);
// Calculate the video frame number that we should be writing.
realFrameNr = Mathf.RoundToInt ((Time.realtimeSinceStartup - captureStartTime) * vi.framerate);
// If the loop is being executed too seldom compared to vi.framerate, write a warning to console.
if (realFrameNr - lastRealFrameNr > 1) {
Debug.LogWarning ("Output framerate too high, possibly just skipped " + (realFrameNr - lastRealFrameNr) + " frames");
}
// Write as many frames as we need. Normally this is 0 or 1, but can be higher (see the warning a few lines above)
while (lastRealFrameNr < realFrameNr) {
remux.WriteNextVideoFrame (buf, bytesCnt);
lastRealFrameNr ++;
}
// Give control back to Unity for one frame
yield return 1;
} while(realFrameNr < 150);
// We're done. Close the remux and streamer
remux.Shutdown ();
streamer.Shutdown ();
Debug.Log ("Done capturing");
}
void DropHalfTheFramesRemux()
{
// In this example we're going one level deeper in the API and work directly
// with Demux class. We could use MoviePlayerUtil.Load too, but for remuxing
// we don't need Decoders to be instantiated, because we're just copying encoded
// frame bytes around.
//
// Since we're not using decoders, we're not referencing anything from Unity API.
// Therefore it's possible to run it in separate thread.
RunInBackgroundOrNot (delegate() {
// Instantiate a demux for an input stream based on stream type.
Stream instream = File.OpenRead (infile);
Demux demux = Demux.forSource (instream);
demux.Init (instream);
// Instantiate a remux for an output stream. Here we have to explicity
// instantiate the remux we want, in this case, AviRemux, and set its
// properties. Since we're not doing much here, we can use the same
// videoStreamInfo and audioStreamInfo for remux as demux. For the video
// however we clone the stream info, because we want to change it. Since
// we're going to drop every other frame, we also need to lower the
// video framerate.
Stream outstream = File.OpenWrite (outfile);
Remux remux = new AviRemux ();
var remuxVideoStreamInfo = new VideoStreamInfo (demux.videoStreamInfo);
remuxVideoStreamInfo.framerate /= 2;
remux.Init (outstream, remuxVideoStreamInfo, demux.audioStreamInfo);
// Just sum buffers and variables needed later
byte[] videoBuffer, audioBuffer;
int videoBytesRead, audioBytesRead;
// Loop until we've processed all the video frames. If we wanted to run this code
// in main Unity thread without blocking, then we could wrap it all in a coroutine
// and do "yield return 1" inside the loop.
do {
// Here we're using sequential access to video (and audio) stream. The same could
// be achieved with random access, but then only demuxes that can seek in a file
// can be used (no streaming from network or webcam).
videoBytesRead = demux.ReadVideoFrame (out videoBuffer);
if (videoBytesRead > 0) {
// Read the exact number of audio samples that are to be played during this frame
int samplesPerVideoFrame = (int)(demux.audioStreamInfo.sampleRate / demux.videoStreamInfo.framerate);
audioBytesRead = demux.ReadAudioSamples (out audioBuffer, samplesPerVideoFrame);
// Only write every second video frame, but all the audio samples. The total stream
// lengths will still be the same, because we've set the framerate for remuxed stream
// to half of the original.
if (demux.VideoPosition % 2 == 1) {
remux.WriteNextVideoFrame (videoBuffer, videoBytesRead);
}
remux.WriteNextAudioSamples (audioBuffer, audioBytesRead);
}
} while(videoBytesRead > 0);
// Close the remux and demux. While it's possible to leave demux just hanging there unclosed and
// possibly introducing a memory leak, we have to Close the remux for the output to be playable.
// The reason is that AviDemux needs to write all unwritten index chunks and update the avi header
// after all frames have been written.
remux.Shutdown ();
demux.Shutdown ();
});
}