I am trying to create a low latency playback of data received over a network. Due to the requirement of low latency, I selected WasapiOut (have tried both shared/exclusive, using/not using event sync, 25 or 50 ms). I have a MixingSampleProvider (IEEE, 44.1 kHz, tried with one or two channels) feeding into the WasapiOut as I will have several streams to play.
If I use shared access, I get an exception from HRESULT 0x88890003, if I use exclusive access, I get "Can't find a supported format to use".
I based this on the NAudioDemo app, the Audio Playback Demo. It seems to me the only difference is that I want a mixer in the chain. Is that not possible?
var waveFormat = WaveFormat.CreateIeeeFloatWaveFormat(44100, 1);
this.mixer = new MixingSampleProvider(waveFormat)
{
ReadFully = true
};
try
{
using (this.audioOut = new WasapiOut(selectedDevice, AudioClientShareMode.Exclusive, false, 25))
{
this.audioOut.Init(this.mixer);
this.audioOut.Play();
}
}
catch (Exception e)
{
Console.WriteLine(e);
throw;
}
It's likely because it is mono. Try supplying a stereo source and I expect that will work
Related
I am currently trying to implement the Java web service(Rest API) where the endpoint creates the device in the IoTHub and updates the device twin.
There are two methods available in the azure-iot sdk. One is
addDevice(deviceId, authenticationtype)
and another is to
addDeviceAsync(deviceId, authenticationtype)
I just wanted to figure out which one should I use in the web service(as a best practice). I am not very strong in MultiThreading/Concurrency so was wondering to receive people's expertise on this. Any suggestion/Link related to this is much appreciated
Thanks.
The Async version of AddDevice is basically the same. If you use AddDeviceAsync then a thread is created to run the AddDevice call so you are not blocked on it.
Check the code#L269 of RegistryManager doing exactly that: https://github.com/Azure/azure-iot-sdk-java/blob/master/service/iot-service-client/src/main/java/com/microsoft/azure/sdk/iot/service/RegistryManager.java#L269
public CompletableFuture<Device> addDeviceAsync(Device device) throws IOException, IotHubException
{
if (device == null)
{
throw new IllegalArgumentException("device cannot be null");
}
final CompletableFuture<Device> future = new CompletableFuture<>();
executor.submit(() ->
{
try
{
Device responseDevice = addDevice(device);
future.complete(responseDevice);
}
catch (IOException | IotHubException e)
{
future.completeExceptionally(e);
}
});
return future;
}
You can as well build your own async wrapper and call AddDevice() from there.
Problem Statement
Context
I'm a Software Engineer in Test running order permutations of Restaurant Menu Items to confirm that they succeed order placement w/ the POS
In short, this POSTs a JSON payload to an endpoint which then validates the order w/ a POS to define success/fail/other
Where POS, and therefore Transactions per Second (TPS), may vary, but each Back End uses the same core handling
This can be as high as ~22,000 permutations per item, in easily manageable JSON size, that need to be handled as quickly as possible
The Network can vary wildly depending upon the Restaurant, and/or Region, one is testing
E.g. where some have a much higher latency than others
Therefore, the HTTPClient should be able to intelligently negotiate the same content & endpoint regardless of this
Direct Problem
I'm using Apache's HTTP Client 5 w/ PoolingAsyncClientConnectionManager to execute both the GET for the Menu contents, and the POST to check if the order succeeds
This works out of the box, but sometimes loses connections w/ Stream Refused, specifically:
org.apache.hc.core5.http2.H2StreamResetException: Stream refused
No individual tuning seems to work across all network contexts w/ variable latency, that I can find
Following the stacktrace seems to indicate it is that the stream had closed already, therefore needs a way to keep it open or not execute an already-closed connection
if (connState == ConnectionHandshake.GRACEFUL_SHUTDOWN) {
throw new H2StreamResetException(H2Error.PROTOCOL_ERROR, "Stream refused");
}
Some Attempts to Fix Problem
Tried to use Search Engines to find answers but there are few hits for HTTPClient5
Tried to use official documentation but this is sparse
Changing max connections per route to a reduced number, shifting inactivity validations, or connection time to live
Where the inactivity checks may fix the POST, but stall the GET for some transactions
And that tuning for one region/restaurant may work for 1 then break for another, w/ only the Network as variable
PoolingAsyncClientConnectionManagerBuilder builder = PoolingAsyncClientConnectionManagerBuilder
.create()
.setTlsStrategy(getTlsStrategy())
.setMaxConnPerRoute(12)
.setMaxConnTotal(12)
.setValidateAfterInactivity(TimeValue.ofMilliseconds(1000))
.setConnectionTimeToLive(TimeValue.ofMinutes(2))
.build();
Shifting to a custom RequestConfig w/ different timeouts
private HttpClientContext getHttpClientContext() {
RequestConfig requestConfig = RequestConfig.custom()
.setConnectTimeout(Timeout.of(10, TimeUnit.SECONDS))
.setResponseTimeout(Timeout.of(10, TimeUnit.SECONDS))
.build();
HttpClientContext httpContext = HttpClientContext.create();
httpContext.setRequestConfig(requestConfig);
return httpContext;
}
Initial Code Segments for Analysis
(In addition to the above segments w/ change attempts)
Wrapper handling to init and get response
public SimpleHttpResponse getFullResponse(String url, PoolingAsyncClientConnectionManager manager, SimpleHttpRequest req) {
try (CloseableHttpAsyncClient httpclient = getHTTPClientInstance(manager)) {
httpclient.start();
CountDownLatch latch = new CountDownLatch(1);
long startTime = System.currentTimeMillis();
Future<SimpleHttpResponse> future = getHTTPResponse(url, httpclient, latch, startTime, req);
latch.await();
return future.get();
} catch (IOException | InterruptedException | ExecutionException e) {
e.printStackTrace();
return new SimpleHttpResponse(999, CommonUtils.getExceptionAsMap(e).toString());
}
}
With actual handler and probing code
private Future<SimpleHttpResponse> getHTTPResponse(String url, CloseableHttpAsyncClient httpclient, CountDownLatch latch, long startTime, SimpleHttpRequest req) {
return httpclient.execute(req, getHttpContext(), new FutureCallback<SimpleHttpResponse>() {
#Override
public void completed(SimpleHttpResponse response) {
latch.countDown();
logger.info("[{}][{}ms] - {}", response.getCode(), getTotalTime(startTime), url);
}
#Override
public void failed(Exception e) {
latch.countDown();
logger.error("[{}ms] - {} - {}", getTotalTime(startTime), url, e);
}
#Override
public void cancelled() {
latch.countDown();
logger.error("[{}ms] - request cancelled for {}", getTotalTime(startTime), url);
}
});
}
Direct Question
Is there a way to configure the client such that it can handle for these variances on its own without explicitly modifying the configuration for each endpoint context?
Fixed w/ Combination of the below to Assure Connection Live/Ready
(Or at least is stable)
Forcing HTTP 1
HttpAsyncClients.custom()
.setConnectionManager(manager)
.setRetryStrategy(getRetryStrategy())
.setVersionPolicy(HttpVersionPolicy.FORCE_HTTP_1)
.setConnectionManagerShared(true);
Setting Effective Headers for POST
Specifically the close header
req.setHeader("Connection", "close, TE");
Note: Inactivity check helps, but still sometimes gets refusals w/o this
Setting Inactivity Checks by Type
Set POSTs to validate immediately after inactivity
Note: Using 1000 for both caused a high drop rate for some systems
PoolingAsyncClientConnectionManagerBuilder
.create()
.setValidateAfterInactivity(TimeValue.ofMilliseconds(0))
Set GET to validate after 1s
PoolingAsyncClientConnectionManagerBuilder
.create()
.setValidateAfterInactivity(TimeValue.ofMilliseconds(1000))
Given the Error Context
Tracing the connection problem in stacktrace to AbstractH2StreamMultiplexer
Shows ConnectionHandshake.GRACEFUL_SHUTDOWN as triggering the stream refusal
if (connState == ConnectionHandshake.GRACEFUL_SHUTDOWN) {
throw new H2StreamResetException(H2Error.PROTOCOL_ERROR, "Stream refused");
}
Which corresponds to
connState = streamMap.isEmpty() ? ConnectionHandshake.SHUTDOWN : ConnectionHandshake.GRACEFUL_SHUTDOWN;
Reasoning
If I'm understanding correctly:
The connections were being un/intentionally closed
However, they were not being confirmed ready before executing again
Which caused it to fail because the stream was not viable
Therefore the fix works because (it seems)
Given Forcing HTTP1 allows for a single context to manage
Where HttpVersionPolicy NEGOTIATE/FORCE_HTTP_2 had greater or equivalent failures across the spectrum of regions/menus
And it assures that all connections are valid before use
And POSTs are always closed due to the close header, which is unavailable to HTTP2
Therefore
GET is checked for validity w/ reasonable periodicity
POST is checked every time, and since it is forcibly closed, it is re-acquired before execution
Which leaves no room for unexpected closures
And otherwise the potential that it was incorrectly switching to HTTP2
Will accept this until a better answer comes along, as this is stable but sub-optimal.
My, already "legacy" by now, implementation of a pub/sub solution using ServiceStack quickly ran out of clients, when it reached the 20 client limit.
We do something like:
_redisConsumer = MqClientFactory.Instance.GetRedisClient(); // Returns a IRedisClient
_subscription = _redisConsumer.CreateSubscription();
_subscription.OnSubscribe = channel => CoreLog.Instance.Info($"Subscription started on {eventChannelName}");
_subscription.OnUnSubscribe = channel => CoreLog.Instance.Warning($"Unsubscribed from {eventChannelName}");
_subscription.OnMessage = (channel, msg) =>
{
try
{
onMessageReceived(CoreRequestJsonEnvelope.CreateCoreRequestFromJson(msg));
}
catch (Exception ex)
{
CoreLog.Instance.Exception(ex);
}
};
// Since it blocks execution, we put this in a Task:
Task.Run(() =>
{
try
{
_subscription.SubscribeToChannels(eventChannelName); // blocking
}
catch(Exception e)
{
}
});
and when we have enough different channels to listen too, it runs out.
I then thought, that maybe instead of taking a new IRedisClient for each subscription, I could use the same IRedisClient for all of them, so:
_redisConsumer = mySavedRedisClient;
...
but that returns Unknown reply on multi-request after a few seconds/executions.
Lastly, I looked at the RedisPubSubServer, but it seems that I need to specify the channels in the constructor, and I cannot change after that. I do need to add and remove channels in runtime, and channels are not known from start.
What is the recommended approach?
Is it to increaase the Max-limit and continue as before?
Is it to use RedisPubSub, but how to handle dynamic channels?
What does "unknown reply on multi-request" actually mean?
Thanks!
It's not clear what 20 client limit you're referring to & how the client limit is dependent on channels or subscribers, but if this is your App own limit than sounds like increasing it would be the easiest solution.
ServiceStack.Redis doesn't support changing the subscribed channels after a subscription has started. Instead of managing the IRedisSubscription yourself you may want to consider ServiceStack.Redis Managed Pub/Sub Server which manages the background subscription thread with added resiliency and support for auto retries.
Whilst you can't change the subscribed channels at runtime, you can modify the modify the Channels collection and restart the subscription to create a new subscription to the updated channels list, e.g:
var pubSub = new RedisPubSubServer(clientsManager, chan1);
pubSub.Start();
//...
pubSub.Channels = new[] { chan1, chan2 };
pubSub.Restart();
Otherwise depending on your use-case you may be able to subscribe to a channel pattern which allows you to subscribe to a multiple dynamic channels matching wildcard channel pattern:
var pubSub = new RedisPubSubServer(clientsManager) {
ChannelsMatching = new[] { "chan:*" }
}
.Start();
Where it will handle any messages clients send that matches the channel pattern.
In my project i have recorded sound using mediaplayer and save as .3gp file but when i want to play it using some audio effect or fast forwarding or change pitch of audio while playing. i have used mediaplayer but not working.then i used audiotrack but audiotrack takes only bytestream as input to play. i just want to play .3gp file and change pitch while playing.. i use this one below.
Help me...thanks in advance...
public void play() {
File path = new File(
Environment.getExternalStorageDirectory().getAbsolutePath()
+ "/sdcard/meditest/");
File[] f=path.listFiles();
isPlaying=true;
int bufferSize = AudioTrack.getMinBufferSize(outfrequency,
channelConfigurationout, audioEncoding);
short[] audiodata = new short[bufferSize];
try {
DataInputStream dis = new DataInputStream(
new BufferedInputStream(new FileInputStream(
f[0])));
audioTrack = new AudioTrack(
AudioManager.STREAM_MUSIC, outfrequency,
channelConfigurationout, audioEncoding, bufferSize,
AudioTrack.MODE_STREAM);
audioTrack.setPlaybackRate((int) (frequency*1.5));
AudioManager audioManager = (AudioManager)this.getSystemService(Context.AUDIO_SERVICE);
// Set the volume of played media to maximum.
audioTrack.setStereoVolume(1.0f,1.0f);
Log.d("Clapper","player start");
audioTrack.play();
while (isPlaying && dis.available() > 0) {
int i = 0;
while (dis.available() > 0 && i < audiodata.length) {
audiodata[i] = dis.readShort();
i++;
if(i/50==0)
Log.d("Clapper", "playing now"+i);
}
audioTrack.write(audiodata, 0, audiodata.length);
}
Log.d("Clapper","AUDIO LENGTH: "+String.valueOf(audiodata));
dis.close();
audioTrack.stop();
} catch (Throwable t) {
Log.e("AudioTrack", "Playback Failed");
}
Log.d("Clapper","AUDIO state: "+String.valueOf(audioTrack.getPlayState()));
talkAnimation.stop();
if(audioTrack.getPlayState()!=AudioTrack.PLAYSTATE_PLAYING)
{
runOnUiThread(new Runnable() {
public void run() {
// TODO Auto-generated method stub
imgtalk.setBackgroundResource(R.drawable.talk1);
}
});
}
}
I tried library called Sonic. Its basically for Speech as it use PSOLA algo to change pitch and tempo.
Sonic Library
i got your problem .Media player does not support cha
Consider using a SoundPool
http://developer.android.com/reference/android/media/SoundPool.html
It supports changing the pitch in realtime while playing
The playback rate can also be changed. A playback rate of 1.0 causes the sound to play at its original frequency (resampled, if necessary, to the hardware output frequency). A playback rate of 2.0 causes the sound to play at twice its original frequency, and a playback rate of 0.5 causes it to play at half its original frequency. The playback rate range is 0.5 to 2.0.
Once the sounds are loaded and play has started, the application can trigger sounds by calling SoundPool.play(). Playing streams can be paused or resumed, and the application can also alter the pitch by adjusting the playback rate in real-time for doppler or synthesis effects.
http://developer.android.com/reference/android/media/SoundPool.html#setRate(int, float)
IF you want to change pitch while playing sound you have to use sound pool .this is the best way to do this.you can fast forward your playing by some amount and see you feel that pitch has been changed.
In my WP7 application I have downloaded 200 images from Web and saved in isolated storage .When debug all the images are loaded in panorama view by queue method and I can view when it is connected to pc. after disconnect it from pc when i open the application and navigate the images it shows some images and terminated.
if (i < 150)
{
WebClient m_webClient = new WebClient();
Uri m_uri = new Uri("http://d1mu9ule1cy7bp.cloudfront.net/2012//pages/p_" + i + "/mobile_high.jpg");
m_webClient.OpenReadCompleted += new OpenReadCompletedEventHandler(webClient_OpenReadCompleted);
m_webClient.OpenReadAsync(m_uri);
}
void webClient_OpenReadCompleted(object sender, OpenReadCompletedEventArgs e)
{
int count;
try
{
Stream stream = e.Result;
byte[] buffer = new byte[1024];
using (IsolatedStorageFile isf = IsolatedStorageFile.GetUserStoreForApplication())
{
//isf.Remove();
using (System.IO.IsolatedStorage.IsolatedStorageFileStream isfs = new IsolatedStorageFileStream("IMAGES" + loop2(k) + ".jpg", FileMode.Create, isf))
{
count = 0;
while (0 < (count = stream.Read(buffer, 0, buffer.Length)))
{
isfs.Write(buffer, 0, count);
}
stream.Close();
isfs.Close();
}
}
}
catch (Exception ex)
{
MessageBox.Show(ex.ToString());
}
}
I think that your problem is that if you load too many images at once in a loop the moment you go out of the loop and give focus back to the UI thread all the Garbage Collection on the bitmap images is done.
This article explains it a bit better and provides with a solution.
I also had this problem and came up with my own solution. I had a dictonairy with image url that needed to be loaded, but you can easily alter this for your scenario.
This SO question is also about this problem (loading multiple images and crash (Exception)). It also has Microsofts response to it, I based my solution on their response.
In my solution I use the dispatcher to return to the UI thread and thus making sure the garbage of the image and bitmaps used was cleaned.
private void LoadImages(List<string> sources)
{
List<string>.Enumerator iterator = sources.GetEnumerator();
this.Dispatcher.BeginInvoke(() => { LoadImage(iterator); });
}
private void LoadImage(List<string>.Enumerator iterator)
{
if (iterator.MoveNext())
{
//TODO: Load the image from iterator.Current
//Now load the next image
this.Dispatcher.BeginInvoke(() => { LoadImage(iterator); });
}
else
{
//Done loading images
}
}
After talking on Skype I reviewed his code and found out his problem was with his Isolated Storage Explorer. It couldnt connect to his pc so it gave an error. Had nothing to do with the image loading.
I'd be very wary of the memory implications of loading 200 images at once. Have you been profiling the memory usage? Using too much memory could cause your application to be terminated.