Develop Reference

How to fix ExoPlayer error 'native window cannot handle protected buffers'

I keep getting an error when pausing ExoPlayer and putting my app in the background. The stream contains Widevine protected content and ads that are inserted on the server side.
I suspect this mixture of protected and unprotected content to be causing the error but have no idea where to start. Putting the app in the background and resuming it actually works once during the unprotected preroll ad but fails when trying it a second time in the main content.
SurfaceUtils logs the following message: native window cannot handle protected buffers: the consumer should either be a hardware composer or support hardware protection.
Does someone know what this actually means? Unfortunately I am not too familiar with the inner workings of ExoPlayer.
The code in SurfaceUtils.cpp that returns the error might be helpful here:
// Make sure to check whether either Stagefright or the video decoder
// requested protected buffers.
if (usage & GRALLOC_USAGE_PROTECTED) {
// Check if the ANativeWindow sends images directly to SurfaceFlinger.
int queuesToNativeWindow = 0;
err = nativeWindow->query(
nativeWindow, NATIVE_WINDOW_QUEUES_TO_WINDOW_COMPOSER, &queuesToNativeWindow);
if (err != NO_ERROR) {
ALOGE("error authenticating native window: %s (%d)", strerror(-err), -err);
return err;
}
// Check if the consumer end of the ANativeWindow can handle protected content.
int isConsumerProtected = 0;
err = nativeWindow->query(
nativeWindow, NATIVE_WINDOW_CONSUMER_IS_PROTECTED, &isConsumerProtected);
if (err != NO_ERROR) {
ALOGE("error query native window: %s (%d)", strerror(-err), -err);
return err;
}
// Deny queuing into native window if neither condition is satisfied.
if (queuesToNativeWindow != 1 && isConsumerProtected != 1) {
ALOGE("native window cannot handle protected buffers: the consumer should either be a hardware composer or support hardware protection");
return PERMISSION_DENIED;
}
}

AT Commands doesn't work :: WinSock Bluetooth Connection

I'm creating windows application in C++, which connect's PC with mobile via bluetooth and winsock. Allow's you to call and send messages from mobile via computer.
I'm using AT command's to tell mobile what i want to do. Pair with mobile device and force a call with At command
ATD+420******;
works perfect, but all commands for handling SMS like
AT+CMGL, AT+CMGF, AT+CMGS etc.
phone probably doesnt recognize them and returns ERROR.
Here is code which connects PC with mobile via bluetooth and socket:
SOCKADDR_BTH RemoteEndPoint;
RemoteEndPoint.port = 0;
RemoteEndPoint.addressFamily = AF_BTH;
RemoteEndPoint.btAddr = m_foundDevices[m_deviceIndex].Address.ullLong;
RemoteEndPoint.serviceClassId = HandsfreeServiceClass_UUID;
int BTHAddrLength = sizeof(RemoteEndPoint);
// Create the socket.
if ((m_localSocket = socket(AF_BTH, SOCK_STREAM, BTHPROTO_RFCOMM)) == INVALID_SOCKET)
{
// handle error.
}
// Connect the socket.
if ((iResult = connect(m_localSocket, (SOCKADDR *)&RemoteEndPoint, sizeof(RemoteEndPoint))) == INVALID_SOCKET)
{
// handle error.
}
Notice line
RemoteEndPoint.serviceClassId = HandsfreeServiceClass_UUID
I think the problem is here, becouse u cant send sms from Handsfree, but when i use another UUID, it doesnt even pair with mobile.
=== Here is just for info, how am i sending and receiving data from mobile ===
char recvbuf[DEFAULT_BUFLEN] = "";
const char *sendbuf = "AT+CMGL\r";
int len = (int)strlen(sendbuf);
if ((iResult = send(m_localSocket, sendbuf, len, MSG_OOB)) == SOCKET_ERROR)
{
// handle error. return ~0
}
if ((iResult = recv(m_localSocket, recvbuf, recvbuflen, 0)) == SOCKET_ERROR)
{
// handle error. return ~0
}
// Here recvbuf == "\r\nERROR\r\n"
-- I would like to find out the problem, why AT command's for SMS doesnt work.
Thank you for any advices!
If you have any question's about problem, i'll kindly explain.
Regards,
Filip.
EDIT
I found out answer "If you want to send SMS Messages, a Server Socket will be needed on the GSM Device", but after hours of googling i have no clue how to do that. Any suggestion's? Thank you.

odata4j requests metadata too many times

I use the odata4j library to access a WCF Data Service.
This is how I call a Service Method from my Android code:
OQueryRequest<OEntity> l = consumer.getEntities("GetDataList")
.custom("dataId", String.format("'%s'", actualData.ID))
.orderBy("Name").skip(0).top(200);
I checked it with WireShark, and I see that every method call is preceded with 2 calls of metadata information request:
Why? Are they essential? The metadata information is quite heavy, it shouldn't request is every time (not to mention 2 times).
What should I do to prevent odata4j from requesting metadata information so many times?

I found in the source code where the 'extra' request happens (in odata4j/odata4j-core/src/main/java/org/odata4j/consumer/AbstractODataConsumer.java ):
#Override
public EdmEntitySet findEdmEntitySet(String entitySetName) {
EdmEntitySet rt = super.findEdmEntitySet(entitySetName);
if (rt == null && delegate != EdmDataServices.EMPTY) {
refreshDelegate();
rt = super.findEdmEntitySet(entitySetName);
}
return rt;
}
It seems that if the entity set can't be found, the consumer creates an extra roundtrip to the server to get the metadata again (by calling refreshDelegate()):
private void refreshDelegate() {
ODataClientRequest request = ODataClientRequest.get(AbstractODataConsumer.this.getServiceRootUri() + "$metadata");
try {
delegate = AbstractODataConsumer.this.getClient().getMetadata(request);
} catch (ODataProducerException e) {
// to support services that do not expose metadata information
delegate = EdmDataServices.EMPTY;
}
}
I don't quite understand why: maybe it assumes that the server has changed and a new version of the metadata is available so it tries again.
If it fails then it tries to find a function with the given name.
Personally I don't consider this very effective unless the server side is so volatile that it changes between calls.
So, if you have no changing metadata on the server, it is safe to remove the check for the entitySet and let it return as a null:
#Override
public EdmEntitySet findEdmEntitySet(String entitySetName) {
EdmEntitySet rt = super.findEdmEntitySet(entitySetName);
//if (rt == null && delegate != EdmDataServices.EMPTY) {
// refreshDelegate();
// rt = super.findEdmEntitySet(entitySetName);
//}
return rt; //if it is null, then the search for a function will commence
}

IHE and HL7. PCD-01 ACK

I'm trying to get data from a monitor to an Android application and I've took the IHE - PCD-01 transaction as a model.
The scheme is simple, is based on achieve the interconnection between the monitor and the tablet, where the monitor sends constantly information and the application is listening.
But what I don't understand is if I need an ACK or not after every message. Does anyone can help me with this?

TL;DR yes, nothing special here, support the usual HL7 ACK/NACK driven by MSH-15, MSH-16 fields. ACK-ing everything by default is "better safe then sorry"
The document "IHE Patient Care Device (PCD), Technical Framework, Volume 2 (PCD TF-2) Transactions, Revision 1.0 - Final Text, August 12, 2011" available at http://www.ihe.net/technical_framework/upload/ihe_pcd_tf_vol2_ft_2011-08-12.pdf says
..The common static definition of the HL7 acknowledgement (ACK) message is described in Appendix G, "HL7 Implementation Notes"..
which says
G.1 Network Guidelines
The HL7 2.6 standard does not define a network communications protocol. Beginning with HL7 2.2, the definitions of lower layer protocols were moved to the Implementation Guide, but are not HL7 requirements. The IHE Framework makes these recommendations:
Applications shall use the Minimal Lower Layer Protocol defined in Appendix C of the HL7 Implementation Guide.
An application that wants to send a message (initiate a transaction) will initiate a network connection to start the transaction. The receiver application will respond with an acknowledgement or response to query but will not initiate new transactions on this network connection
G.1.1 Acknowledgment Modes
ACKNOWLEDGMENT MESSAGES
Acknowledgment messages may be defined on an application basis. However the simple general acknowledgment message (ACK) may be used where the application does not define a special message (application level acknowledgment) and in other cases as described in Section 2.9, "Message Processing Rules".
The IHE PCD transaction PCD-03 supports „enhanced mode‟ acknowledgements. See discussion under PCD-03 Transactions as well as in B.1 MSH – Message Header Segment and B.2 MSA – Message Acknowledgement Segment
and document "Health Level Seven, Version 2.6 © 2007, Chapter 2: Control" coming from the "HL7 Messaging Standard Version 2.6" package which can be downloaded from http://www.hl7.org/implement/standards/product_brief.cfm?product_id=185 describes the accept and validate behavior in
2.9.2 Message response using the original processing rules
..too long to quote..
2.9.3 Response using enhanced acknowledgement
..too long to quote..
depending on the values of MSH-15 Accept Acknowledgement Type and MSH-16 Application Acknowledgment Type fields in the HL7 message
The above chapters from the HL7 standard contain what you want to read and implement/support.
EDIT:
Simply put, in HL7 protocol in every message sent the sender may request an ACK receipt by flagging appropriate fields in the message header segment. IHE does not remove this rule and does not enforce any other but enables any other convention to be defined on an application basis. Correct expected behavior is defined by the HL7 specification and in order to get it right and create a conforming implementation (without hidden surprises for your 3rd parties) you may need to read it several times (see also Stack Overflow: How can I make my system HL7 certified?)
For example this is how HAPI library handles the ACKing, snippet comes from http://sourceforge.net/p/hl7api/code/764/tree/tags/Root_REL_1_2/hapi-mvn/hapi-base/src/main/java/ca/uhn/hl7v2/protocol/impl/ProcessorImpl.java
/**
* #see ca.uhn.hl7v2.protocol.Processor#cycle(boolean)
*/
public void cycle(boolean expectingAck) throws HL7Exception {
log.debug("In cycle({})", expectingAck);
cleanReservations();
cleanAcceptAcks();
cleanReservedMessages();
Transportable in = null;
try {
if (expectingAck) {
in = tryReceive(myContext.getLocallyDrivenTransportLayer());
} else {
in = tryReceive(myContext.getRemotelyDrivenTransportLayer());
}
} catch (TransportException e) {
try {
Thread.sleep(1000);
} catch (InterruptedException e1) {}
throw e;
}
// log
if (in != null) {
log.debug("Received message: {}", in.getMessage());
} else {
log.debug("Received no message");
}
// If we have a message, handle it
if (in != null) {
String acceptAckNeeded = null;
// String appAckNeeded = null;
String ackCode = null;
String ackId = null;
try {
String[] fieldPaths = {"MSH-15", "MSH-16", "MSA-1", "MSA-2"};
String[] fields = PreParser.getFields(in.getMessage(), fieldPaths);
acceptAckNeeded = fields[0];
// appAckNeeded = fields[1];
ackCode = fields[2];
ackId = fields[3];
} catch (HL7Exception e) {
log.warn("Failed to parse accept ack fields in incoming message", e);
}
if (ackId != null && ackCode != null && ackCode.startsWith("C")) {
long expiryTime = System.currentTimeMillis() + 1000 * 60;
myAcceptAcks.put(ackId, new ExpiringTransportable(in, expiryTime));
} else {
AcceptAcknowledger.AcceptACK ack = AcceptAcknowledger.validate(getContext(), in);
if ((acceptAckNeeded != null && acceptAckNeeded.equals(AL))
|| (acceptAckNeeded != null && acceptAckNeeded.equals(ER) && !ack.isAcceptable())
|| (acceptAckNeeded != null && acceptAckNeeded.equals(SU) && ack.isAcceptable())) {
trySend(myContext.getRemotelyDrivenTransportLayer(), ack.getMessage());
}
if (ack.isAcceptable()) {
if (isReserved(ackId)) {
log.debug("Received expected ACK message with ACK ID: {}", ackId);
removeReservation(ackId);
long expiryTime = System.currentTimeMillis() + 1000 * 60 * 5;
myAvailableMessages.put(ackId, new ExpiringTransportable(in, expiryTime));
} else {
log.debug("Sending message to router");
Transportable out = myContext.getRouter().processMessage(in);
sendAppResponse(out);
}
} else {
// TODO: should we do something more here? Might be nice to
// allow a configurable handler for this situation
log.warn("Incoming message was not acceptable");
}
}
} else {
String transport = expectingAck ? " Locally driven " : "Remotely driven";
log.debug("{} TransportLayer.receive() returned null.", transport);
}
sleepIfNeeded();
log.debug("Exiting cycle()");
}

Thanks for your answer :)
of course that it is better to use an ACK to make sure if the receiver is getting the message but what I wanted to know if it was mandatory or not using the PCD-01 transaction.
I've read your documents and what I've understood is that the use of ACK depends on the MSH-15 and MSH-16 fields content, but with the following information:
An application that wants to send a message (initiate a transaction) will initiate a network connection to start the transaction. The receiver application will respond with an acknowledgement or response to query but will not initiate new transactions on this network connection
I understand that the ACK is only at the beginning of the connection not after every message, is it right?

How to implement GCM HTTP server in Python while avoiding my server's IP being blacklisted by Google?

I'm using Apache, WSGI (mod_wsgi) and Python, to implement a GCM HTTP server as describe in the Android Developer website:
developer.android.com/google/gcm/server.html
At first the code I've implemented on the server side to handle message sending to GCM was as the following:
def send_to_gcm(data):
url = 'https://android.googleapis.com/gcm/send'
no = 1
while True:
try:
request = Request(url=url, data=json.dumps(data))
request.add_header('Authorization','key=AIzXXX')
request.add_header('Content-Type', 'application/json')
res = urlopen(request)
if res.getcode() == 200: return
except Exception: pass
no += 1
#Discard the message
if no == 16: return
#Exponential backoff
tts = randint(2**(no-1), (2**no) -1)
sleep(tts)
data = dict(registration_id=[regid], data=dict(mymessage=themessage))
thread = Thread(target=send_to_gcm, args=(data,))
thread.start()
After a while (about a day) GCM stopped to accept the messages sent by the Server. So I started to dig here and there in the documentation of GCM and I found an important part of the specification I missed before:
developer.android.com/google/gcm/http.html#response
"Honor the Retry-After header if it's included in the response from the GCM server. ... Senders that cause problems risk being blacklisted. ... Happens when the HTTP status code is between 501 and 599, or when the error field of a JSON object in the results array is Unavailable."
So i patched my server code as follow:
def send_to_gcm(data, environ):
url = 'https://android.googleapis.com/gcm/send'
no = 1
while True:
try:
request = Request(url=url, data=json.dumps(data))
request.add_header('Authorization','key=AIzXXX')
request.add_header('Content-Type', 'application/json')
res = urlopen(request)
if res.getcode() == 200: return
except HTTPError as error:
if error.headers.has_key('Retry-After'):
try: tts = int(response_headers['Retry-After'])
except ValueError:
until = datetime.strptime(response_headers, '%a, %d %b %Y %H:%M:%S GMT')
diff = until - datetime.now()
tts = int(diff.total_seconds()) +1
sleep(tts)
no += 1
#Discard the message
if no == 16: return
#Exponential backoff
tts = randint(2**(no-1), (2**no) -1)
sleep(tts)
But actually it's likely my server has been blacklisted and for any request sent I receive a 401 status code and an "Unauthorized" error message. Here my questions:
Is there something wrong in my latest server implementation?
Will the static IP address of my server be unbanned and if yes when?

I was searching for the same subject.
This module may help you
https://github.com/geeknam/python-gcm