How to trace error message in libav - libavcodec

I'm writing a simple program to decode any input audio file into pcm16/mono/wav file, using libav. Or, I supposed it was simple.
After struggling a lot, reading lots of sample code (like avconv/avplay), I've managed to code something that should work.
However, it's not working. The demuxing/decoding parts seems to work fine, but the encoding part failed with the following message:
mathematics.c:61: av_rescale_rnd: Assertion `c > 0' failed.
Here is the code extract:
printf("Fill Frame\n");
avcodec_fill_audio_frame(oframe, _oCodecCtx->channels, _oCodecCtx->sample_fmt, frame->data[0], frame->linesize[0], 0);
printf("Frame filled\n");
ret = avcodec_encode_audio2(_oCodecCtx, &opkt, oframe, &got_packet);
if (ret < 0) {
printf("Error encoding audio frame\n");
return 1;
}
"Fill Frame" And "Frame filled" are displayed before the error appears. So, I think its thrown by avcodec_encode_audio2. However, this function doesn't call av_rescale_rnd in its source code.
So here is the question: is there a way to know who called this function, without modifying/recompiling libav source code?

Related

Opencascade crash when calling calling Transfer()

I have tested two cases:
I use STEPCAFControl_Reader then STEPControl_Reader to read my step file but both methods crash when I call STEPCAFControl_Reader::Transfer, repsectively STEPControl_Reader:: TransferRoots.
By using STEPControl_Reader, I displayed a log on my console, then there is a message like this:
1 F:(BOUNDED_SURFACE,B_SPLINE_SURFACE,B_SPLINE_SURFACE_WITH_KNOTS,GEOMETRIC_REPRESENTATION_ITEM,RATIONAL_B_SPLINE_SURFACE,REPRESENTATION_ITEM,SURFACE): Count of Parameters is not 1 for representation_item
EDIT:
There is a null reference inside TransferRoots() method.
const Handle(Transfer_TransientProcess) &proc = thesession->TransferReader()->TransientProcess();
if (proc->GetProgress().IsNull())
{
//This condition does not exist from the source code
std::cout << "GetProgress is null" << std::endl;
return 0;
}
Message_ProgressSentry PS ( proc->GetProgress(), "Root", 0, nb, 1 );
My app and FreeCAD crash but if I use CAD Assitant which OCC official viewer, it loads.
It looks like comments already provide an answer to the question - or more precisely answers:
STEPCAFControl_Reader::ReadFile() returns reading status, which should be checked before calling STEPCAFControl_Reader::Transfer().
Normally, it is a good practice to put OCCT algorithm into try/catch block and check for OCCT exceptions (Standard_Failure).
Add OCC_CATCH_SIGNALS at the beginning of try statements (required only on Linux) and OSD::SetSignal(false) within working thread creation to redirect abnormal cases (access violation, NULL dereference and others) to C++ exceptions (OSD_Signal which is subclass of Standard_Failure). This may conflict other signal handlers in mixed environment - so check also documentation of other frameworks used by application.
If you catch failures like NULL dereference on calling OCCT algorithm with valid arguments - this is a bug in OCCT which is desirable to be fixed in one or another way, even if input STEP file contains syntax/logical errors triggering such kind of issues. Report the issue on OCCT Bugtracker with sufficient information for reproducing bug, including sample files - it is not helpful to developers just saying that OCCT crashes somewhere. Consider also contributing into this open source project by debugging OCCT code and suggesting patches.
Check STEP file reading log for possible errors in the file itself. Consider reporting an issue to system producing a broken file, even if main file content can be loaded by STEP readers.
It is a common practice to use OSD::SetSignal() within OCCT-based applications (like CAD Assistant) to improve their robustness on non-fatal errors in application/OCCT code. It is more user friendly reporting an internal error message instead of silently crashing.
But it should be noted, that OSD::SetSignal() doesn't guarantee application not being crashed nor that application can work properly after catching such failure - due to asynchronous nature of some signals, the memory can be already corrupted at the moment, when C++ exception has been raised leading to all kinds of undesired behavior. For that reason, it is better not ignoring such kind of exceptions, even if it looks like application works fine with them.
OSD::SetSignal(false); // should be called ones at application startup
STEPCAFControl_Reader aReader;
try
{
OCC_CATCH_SIGNALS // necessary for redirecting signals on Linux
if (aReader.ReadFile (theFilePath) != IFSelect_RetDone) { return false; }
if (!aReader.Transfer (myXdeDoc)) { return false; }
}
catch (Standard_Failure const& theFailure)
{
std::cerr << "STEP import failed: " << theFailure.GetMessageString() << "\n";
return false;
}
return true;

CLIPS (clear) command fails / throws exception in pyclips

I have a pyclips / clips program for which I wrote some unit tests using pytest.
Each test case involes an initial clips.Clear() followed by the execution of real clips COOL code via clips.Load(rule_file.clp). Running each test individually works fine.
Yet, when telling pytest to run all tests, some fail with ClipsError: S03: environment could not be cleared. In fact, it depends on the order of the tests in the .py file. There seem to be test cases, that cause the subsequent test case to throw the exception.
Maybe some clips code is still "in use" so that the clearing fails?
I read here that (clear)
Clears CLIPS. Removes all constructs and all associated data structures (such as facts and instances) from the CLIPS environment. A clear may be performed safely at any time, however, certain constructs will not allow themselves to be deleted while they are in use.
Could this be the case here? What is causing the (clear) command to fail?
EDIT:
I was able to narrow down the problem. It occurs under the following circumstances:
test_case_A comes right before test_case_B.
In test_case_A there is a test such as
(test (eq (type ?f_bio_puts) clips_FUNCTION))
but f_bio_puts has been set to
(slot f_bio_puts (default [nil]))
So testing the type of a slot variable, which has been set to [nil] initially, seems to cause the (clear) command to fail. Any ideas?
EDIT 2
I think I know what is causing the problem. It is the test line. I adapted my code to make it run in the clips Dialog Windows. And I got this error when loading via (batch ...)
[INSFUN2] No such instance nil in function type.
[DRIVE1] This error occurred in the join network
Problem resided in associated join
Of pattern #1 in rule part_1
I guess it is a bug of pyclips that this is masked.
Change the EnvClear function in the CLIPS source code construct.c file adding the following lines of code to reset the error flags:
globle void EnvClear(
void *theEnv)
{
struct callFunctionItem *theFunction;
/*==============================*/
/* Clear error flags if issued */
/* from an embedded controller. */
/*==============================*/
if ((EvaluationData(theEnv)->CurrentEvaluationDepth == 0) &&
(! CommandLineData(theEnv)->EvaluatingTopLevelCommand) &&
(EvaluationData(theEnv)->CurrentExpression == NULL))
{
SetEvaluationError(theEnv,FALSE);
SetHaltExecution(theEnv,FALSE);
}

Simple UDP socket in VC++ MFC

I have been trying to write a working program that takes in data from a UDP socket and displays it in an edit control box as you receive the data (My exposure to c++ is also only about a week :P have only done embedded C code before). I have a working program that can send and output data on a button click but I want something that can do it in real time. The aim is scale this up into a larger GUI program that can send control data to hardware and get responses from them.
I have run into various problems including:
The program just not executing my OnReceivefunction (derived from
CAsyncSocket)
Getting the OnReceive function to run on a separate thread so that it can still run after a button has been clicked sending a control packet to the client then waiting for a response in a while loop
Not being able to output the data in the edit box (tried using both CEdit and CString)
ReplaceSel error saying that the type char is incompatible with LPCTSTR
My code is based on this codeproject.com tutorial, being almost exactly what I want but I get the error in 4.
EDIT: the error in 4. disappears when I change it to a TCHAR but then it outputs random chinese characters. The codeproject.com tutorial outputs the correct characters regardless of char or TCHAR declaration. When debugged my code has type wchar_t instead type char like the other code.
Chinese output
In the working program echoBuffer[0] the character sent and displayed was a 1
UINT ReceiveData(LPVOID pParam)
{
CTesterDlg *dlg = (CTesterDlg*)pParam;
AfxSocketInit(NULL);
CSocket echoServer;
// Create socket for sending/receiving datagrams
if (echoServer.Create(12345, SOCK_DGRAM, NULL) == 0)
{
AfxMessageBox(_T("Create() failed"));
}
for (;;)
{ // Run forever
// Client address
SOCKADDR_IN echoClntAddr;
// Set the size of the in-out parameter
int clntAddrLen = sizeof(echoClntAddr);
// Buffer for echo string
char echoBuffer[ECHOMAX];
// Block until receive message from a client
int recvMsgSize = echoServer.ReceiveFrom(echoBuffer, ECHOMAX, (SOCKADDR*)&echoClntAddr, &clntAddrLen, 0);
if (recvMsgSize < 0)
{
AfxMessageBox(_T("RecvFrom() failed"));
}
echoBuffer[recvMsgSize] = '\0';
dlg->m_edit.ReplaceSel(echoBuffer);
dlg->m_edit.ReplaceSel(_T("\r\n"));
}
}
After reading the link that #IInspectable provided about working with strings and checking the settings differences between the two programs it became clear that the issue lay with an incorrect conversion to UNICODE. My program does not require it so I disabled it.
This has cleared up the issue in 4. and provided solutions for 2 and 3.
I also think I know why another instance of my program would not run OnReceivein 1. because that file was not being defined by one that was already being run by the program, but that is now irrelevant.

Can't process quickfix messages written in file

In my C++ QuickFix application, I am recording all MarketDataIncrementalRefresh messages i am getting into a file. This is being done using the following code:
void Application::onMessage(const FIX44::MarketDataIncrementalRefresh& message, const FIX::SessionID&)
{
ofstream myfile("tapedol.txt", std::ios::app);
myfile << message << endl << endl;
}
This part's working just fine. The problem occurs when I try to load the message later on.
FIX::Message msg
ifstream myfile("tapedol.txt");
getline(myfile,aux);
msg = aux;
msg.getField(55);
The program crashes every time it executes the last line. I suspect the problem is at the assignment to msg, but i'm not sure. If it is, what is the correct way to do such assignment? If not, how can I process the data within tapedol.txt, so that a message of type MarketDataIncremental refresh would be generated for each string in the file?
Your question is not complete enough to provide a full answer, but I do see one red flag:
msg.getField(55);
The Symbol field is not a top-level field of MarketDataIncrementalRefresh (it's inside the NoMDEntries repeating group), so this line will fail. I think it would raise a FieldNotFound exception.
My C++ is rusty, but you should be able to catch an exception or something that should tell you exactly what line is erroring out. Barring that, you need to open up a debugger. Just saying "it crashed" means you quit looking too soon.

AudioSessionInitialize returning inscrutable error code

I'm calling AudioSessionInitialize like so
OSStatus result = AudioSessionInitialize(NULL,NULL,interruptionListener,NULL);
and getting the result 0xbfffde94 (i.e. -1073750040) which doesn't match anything in the documentation, which are all readable 4CC's like '!ini' and so forth.
The good news is that it seems like the call worked. Nevertheless, can anyone shed light on this error code?
EDIT: The above error code is returned in the simulator. On the device the error code is 2fffe810.
Since these results are bogus and not defined or described by Apple, I am left with only but one assumption; you have a weird mix of Frameworks installed - possibly old versions mixed with newer ones. So all I could recommend is to reinstall the entire iPhone SDK.
I figured it out. I'm an idiot. There was an error in the macro I had wrapping the call & reporting the error, which called the AudioSessionInitialize twice. That doesn't quite explain the error code I saw, but it sure isn't worth wondering about.
UPDATE: Actually this is pretty slapstick so I'm going to explain.
The offending macro was originally:
#define CHECK(S) { OSStatus err = (S); if (S) printf("Error %x at \"%s\"\n", err, #S);}
so bug #1 is the if (S) which should be if if (err). Hence I'm repeating every call to the audio system, which explains various other weird things, so I'm very happy I tried to figure out what had seemed like a harmless anomaly. In this case the second call complained that the audio session was already initialized.
But why the weird error code? I wanted to see the 4CC's so I changed the macro to this, carrying the error along:
#define CHECK(S) { OSStatus err[2] = {S,0}; if (S) printf("Error %x '%4s' at \"%s\"\n", err, &err, #S); }
(The second OSStatus of 0 terminates the string defined by the 4CC first OSStatus, so I can print it with format %s.) But I forgot to change err to err[0], so it was indeed printing the address of the err array. This I'm pretty sure is correct now:
#define CHECK(S) { OSStatus err[2] = {S,0}; if (*err) printf("Error %x '%4s' at \"%s\"\n", *err, err, #S); }
Look at the OSStatus variable in the debugger's list of variables (lower left). Right click on it and select View Value As->Bytes (Hex with ASCII). Read the 4-letter code backwards.* This should match one of the documented result codes.
A value of 1768843636 is 74 69 6e 69 when viewed this way. Next to that the debug window shows 'tini'. Turn that around and you get 'init', which the documentation says is kAudioSessionAlreadyInitialized.
*No, I don't know why.