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Here is my audio init code. My app responds when queue buffers are ready, but all data in buffer is zero. Checking sound in system preferences shows that USB Audio CODEC in sound input dialog is active. AudioInit() is called right after app launches.
{
#pragma mark user data struct
typedef struct MyRecorder
{
AudioFileID recordFile;
SInt64 recordPacket;
Float32 *pSampledData;
MorseDecode *pMorseDecoder;
} MyRecorder;
#pragma mark utility functions
void CheckError(OSStatus error, const char *operation)
{
if(error == noErr) return;
char errorString[20];
// see if it appears to be a 4 char code
*(UInt32*)(errorString + 1) = CFSwapInt32HostToBig(error);
if (isprint(errorString[1]) && isprint(errorString[2]) &&
isprint(errorString[3]) && isprint(errorString[4]))
{
errorString[0] = errorString[5] = '\'';
errorString[6] = '\0';
}
else
{
sprintf(errorString, "%d", (int)error);
}
fprintf(stderr, "Error: %s (%s)\n", operation, errorString);
}
OSStatus MyGetDefaultInputDeviceSampleRate(Float64 *outSampleRate)
{
OSStatus error;
AudioDeviceID deviceID = 0;
AudioObjectPropertyAddress propertyAddress;
UInt32 propertySize;
propertyAddress.mSelector = kAudioHardwarePropertyDefaultInputDevice;
propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
propertyAddress.mElement = 0;
propertySize = sizeof(AudioDeviceID);
error = AudioObjectGetPropertyData(kAudioObjectSystemObject,
&propertyAddress,
0,
NULL,
&propertySize,
&deviceID);
if(error)
return error;
propertyAddress.mSelector = kAudioDevicePropertyNominalSampleRate;
propertyAddress.mScope = kAudioObjectPropertyScopeGlobal;
propertyAddress.mElement = 0;
propertySize = sizeof(Float64);
error = AudioObjectGetPropertyData(deviceID,
&propertyAddress,
0,
NULL,
&propertySize,
outSampleRate);
return error;
}
static int MyComputeRecordBufferSize(const AudioStreamBasicDescription *format,
AudioQueueRef queue,
float seconds)
{
int packets, frames, bytes;
frames = (int)ceil(seconds * format->mSampleRate);
if(format->mBytesPerFrame > 0)
{
bytes = frames * format->mBytesPerFrame;
}
else
{
UInt32 maxPacketSize;
if(format->mBytesPerPacket > 0)
{
// constant packet size
maxPacketSize = format->mBytesPerPacket;
}
else
{
// get the largest single packet size possible
UInt32 propertySize = sizeof(maxPacketSize);
CheckError(AudioQueueGetProperty(queue,
kAudioConverterPropertyMaximumOutputPacketSize,
&maxPacketSize,
&propertySize),
"Couldn't get queues max output packet size");
}
if(format->mFramesPerPacket > 0)
packets = frames / format->mFramesPerPacket;
else
// worst case scenario: 1 frame in a packet
packets = frames;
// sanity check
if(packets == 0)
packets = 1;
bytes = packets * maxPacketSize;
}
return bytes;
}
extern void bridgeToMainThread(MorseDecode *pDecode);
static int callBacks = 0;
// ---------------------------------------------
static void MyAQInputCallback(void *inUserData,
AudioQueueRef inQueue,
AudioQueueBufferRef inBuffer,
const AudioTimeStamp *inStartTime,
UInt32 inNumPackets,
const AudioStreamPacketDescription *inPacketDesc)
{
MyRecorder *recorder = (MyRecorder*)inUserData;
Float32 *pAudioData = (Float32*)(inBuffer->mAudioData);
recorder->pMorseDecoder->pBuffer = pAudioData;
recorder->pMorseDecoder->bufferSize = inNumPackets;
bridgeToMainThread(recorder->pMorseDecoder);
CheckError(AudioQueueEnqueueBuffer(inQueue,
inBuffer,
0,
NULL),
"AudioQueueEnqueueBuffer failed");
printf("packets = %ld, bytes = %ld\n",(long)inNumPackets,(long)inBuffer->mAudioDataByteSize);
callBacks++;
//printf("\ncallBacks = %d\n",callBacks);
//if(callBacks == 0)
//audioStop();
}
static AudioQueueRef queue = {0};
static MyRecorder recorder = {0};
static AudioStreamBasicDescription recordFormat;
void audioInit()
{
// set up format
memset(&recordFormat,0,sizeof(recordFormat));
recordFormat.mFormatID = kAudioFormatLinearPCM;
recordFormat.mChannelsPerFrame = 2;
recordFormat.mBitsPerChannel = 32;
recordFormat.mBytesPerPacket = recordFormat.mBytesPerFrame = recordFormat.mChannelsPerFrame * sizeof(Float32);
recordFormat.mFramesPerPacket = 1;
//recordFormat.mFormatFlags = kAudioFormatFlagsCanonical;
recordFormat.mFormatFlags = kAudioFormatFlagsNativeFloatPacked;
MyGetDefaultInputDeviceSampleRate(&recordFormat.mSampleRate);
UInt32 propSize = sizeof(recordFormat);
CheckError(AudioFormatGetProperty(kAudioFormatProperty_FormatInfo,
0,
NULL,
&propSize,
&recordFormat),
"AudioFormatProperty failed");
recorder.pMorseDecoder = MorseDecode::pInstance();
recorder.pMorseDecoder->m_sampleRate = recordFormat.mSampleRate;
// recorder.pMorseDecoder->setCircularBuffer();
//set up queue
CheckError(AudioQueueNewInput(&recordFormat,
MyAQInputCallback,
&recorder,
NULL,
kCFRunLoopCommonModes,
0,
&queue),
"AudioQueueNewInput failed");
UInt32 size = sizeof(recordFormat);
CheckError(AudioQueueGetProperty(queue,
kAudioConverterCurrentOutputStreamDescription,
&recordFormat,
&size), "Couldn't get queue's format");
// set up buffers and enqueue
const int kNumberRecordBuffers = 3;
int bufferByteSize = MyComputeRecordBufferSize(&recordFormat, queue, AUDIO_BUFFER_DURATION);
for(int bufferIndex = 0; bufferIndex < kNumberRecordBuffers; bufferIndex++)
{
AudioQueueBufferRef buffer;
CheckError(AudioQueueAllocateBuffer(queue,
bufferByteSize,
&buffer),
"AudioQueueAllocateBuffer failed");
CheckError(AudioQueueEnqueueBuffer(queue,
buffer,
0,
NULL),
"AudioQueueEnqueueBuffer failed");
}
}
void audioRun()
{
CheckError(AudioQueueStart(queue, NULL), "AudioQueueStart failed");
}
void audioStop()
{
CheckError(AudioQueuePause(queue), "AudioQueuePause failed");
}
}
This sounds like the new macOS 'microphone privacy' setting, which, if set to 'no access' for your app, will cause precisely this behaviour. So:
Open the System Preferences pane.
Click on 'Security and Privacy'.
Select the Privacy tab.
Click on 'Microphone' in the left-hand pane.
Locate your app in the right-hand pane and tick the checkbox next to it.
Then restart your app and test it.
Tedious, no?
Edit: As stated in the comments, you can't directly request microphone access, but you can detect whether it has been granted to your app or not by calling [AVCaptureDevice authorizationStatusForMediaType: AVMediaTypeAudio].
I have a protobuf message that contains a header and a body. The header has a member called size (reflecting the size of the entire message, i.e header plus body). Since protobuf (AFAIK) does not provide message boundary, I use the size (first element of header and fixed size of 4 bytes) to know how much to slurp from the socket.
Assuming I have read (or recv(2)ed) 4 bytes from the socket, I now need to convert (decode) this to an int so I can instruct recv(2) to slurp that much more.
How do I convert / decode this wire format to an int in C++ land ?
I have tried ParseFromString() but this function is returning a boolean and the doc does not tell me much.
I will show what I think is relevant...lets see
message PsdAgentMsg {
message Header {
fixed32 theSize = 1; // size includes header and message
uint32 theInstanceId = 2;
Type theMsgType = 3;
}
Header theHeader = 1;
oneof theMsg {
abc = 2;
def = 3;
ghi = 4;
klm = 5;
PsdAgentGPCMsg theGPCMsg = 6;
}
}
message PsdAgentGPCMsg {
int32 theCount = 1;
}
...few minutes later..
PsdAgentMsg *msg = new PsdAgentMsg(); // psd msg is header + body
...
rc = recv(sock, buf, 4, 0); // I am simplifying some stuff
std::string sizeString = buf;
...
size_t payloadSize = msg->ParseFromString(sizeString);
I am finding that payloadSize = 0. which is a false being assigned to a size_t. So ParseFromString() does not seem to be the right way to decode the 4 bytes. Again, I need to decode the sizeString to an int. so I can say
recv(sock, buf, payloadSize,0)
Embedded message fields use wire-type 2: length delimited.
That means that it's encoded like this:
<varint tagAndType> <varint messageLength> <theSize> <theInstanceId> <theMsgType>
Where a varint is a base-128 varint as defined in the protobuf encoding specification.
What this means is that theSize isn't at a fixed offset from the beginning of the message. To make things easer, you could send the total size of the message before you send the message itself. i.e. given a message like this:
message PsdAgentMsg {
message Header {
uint32 theInstanceId = 2;
Type theMsgType = 3;
}
Header theHeader = 1;
oneof theMsg {
int32 abc = 2;
string def = 3;
double ghi = 4;
uint32 klm = 5;
PsdAgentGPCMsg theGPCMsg = 6;
}
}
You could send your data as something like this:
PsdAgentMsg msg;
fillOutMessageFields(msg);
std::string encoded_msg = msg.SerializeAsString();
uint32_t size = msg.size();
// First send the message size as a fixed-size integer
size = htonl(size);
send(sockfd, &size, sizeof(size), 0);
// Then send the message itself
send(sockfd, msg.c_str(), msg.size(), 0);
Then you could read it back at the other end like this:
// Read the size
uint32_t size;
rc = recv(sockfd, &size, sizeof(size), 0);
assert(rc == sizeof(size)); // Or proper error handling
size = ntohl(size);
// Read the actual message
std::string encoded_msg(size, '\0');
rc = recv(sockfd, &encoded_msg[0], size, 0);
assert(rc == size); // Or proper error handling
// Parse the message
PsdAgentMsg msg;
msg.ParseFromString(encoded_msg);
I am currently trying to learn audio programming. My goal is to open a wav file, extract everything and play the samples with RtAudio.
I made a WaveLoader class which let's me extract the samples and meta data. I used this guide to do that and I checked that everything is correct with 010 editor. Here is a snapshot of 010 editor showing the structure and data.
And this is how i store the raw samples inside WaveLoader class:
data = new short[wave_data.payloadSize]; // - Allocates memory size of chunk size
if (!fread(data, 1, wave_data.payloadSize, sound_file))
{
throw ("Could not read wav data");
}
If i print out each sample I get : 1, -3, 4, -5 ... which seems ok.
The problem is that I am not sure how I can play them. This is what I've done:
/*
* Using PortAudio to play samples
*/
bool Player::Play()
{
ShowDevices();
rt.showWarnings(true);
RtAudio::StreamParameters oParameters; //, iParameters;
oParameters.deviceId = rt.getDefaultOutputDevice();
oParameters.firstChannel = 0;
oParameters.nChannels = mAudio.channels;
//iParameters.deviceId = rt.getDefaultInputDevice();
//iParameters.nChannels = 2;
unsigned int sampleRate = mAudio.sampleRate;
// Use a buffer of 512, we need to feed callback with 512 bytes everytime!
unsigned int nBufferFrames = 512;
RtAudio::StreamOptions options;
options.flags = RTAUDIO_SCHEDULE_REALTIME;
options.flags = RTAUDIO_NONINTERLEAVED;
//¶meters, NULL, RTAUDIO_FLOAT64,sampleRate, &bufferFrames, &mCallback, (void *)&rawData
try {
rt.openStream(&oParameters, NULL, RTAUDIO_SINT16, sampleRate, &nBufferFrames, &mCallback, (void*) &mAudio);
rt.startStream();
}
catch (RtAudioError& e) {
std::cout << e.getMessage() << std::endl;
return false;
}
return true;
}
/*
* RtAudio Callback
*
*/
int mCallback(void * outputBuffer, void * inputBuffer, unsigned int nBufferFrames, double streamTime, RtAudioStreamStatus status, void * userData)
{
unsigned int i = 0;
short *out = static_cast<short*>(outputBuffer);
auto *data = static_cast<Player::AUDIO_DATA*>(userData);
// if i is more than our data size, we are done!
if (i > data->dataSize) return 1;
// First time callback is called data->ptr is 0, this means that the offset is 0
// Second time data->ptr is 1, this means offset = nBufferFrames (512) * 1 = 512
unsigned int offset = nBufferFrames * data->ptr++;
printf("Offset: %i\n", offset);
// First time callback is called offset is 0, we are starting from 0 and looping nBufferFrames (512) times, this gives us 512 bytes
// Second time, the offset is 1, we are starting from 512 bytes and looping to 512 + 512 = 1024
for (i = offset; i < offset + nBufferFrames; ++i)
{
short sample = data->rawData[i]; // Get raw sample from our struct
*out++ = sample; // Pass to output buffer for playback
printf("Current sample value: %i\n", sample); // this is showing 1, -3, 4, -5 check 010 editor
}
printf("Current time: %f\n", streamTime);
return 0;
}
Inside callback function, when I print out sample values I get exactly like 010 editor? Why isnt rtaudio playing them. What is wrong here? Do I need to normalize sample values to between -1 and 1?
Edit:
The wav file I am trying to play:
Chunksize: 16
Format: 1
Channel: 1
SampleRate: 48000
ByteRate: 96000
BlockAlign: 2
BitPerSample: 16
Size of raw samples total: 2217044 bytes
For some reason it works when I pass input parameters to the openStream()
RtAudio::StreamParameters oParameters, iParameters;
oParameters.deviceId = rt.getDefaultOutputDevice();
oParameters.firstChannel = 0;
//oParameters.nChannels = mAudio.channels;
oParameters.nChannels = mAudio.channels;
iParameters.deviceId = rt.getDefaultInputDevice();
iParameters.nChannels = 1;
unsigned int sampleRate = mAudio.sampleRate;
// Use a buffer of 512, we need to feed callback with 512 bytes everytime!
unsigned int nBufferFrames = 512;
RtAudio::StreamOptions options;
options.flags = RTAUDIO_SCHEDULE_REALTIME;
options.flags = RTAUDIO_NONINTERLEAVED;
//¶meters, NULL, RTAUDIO_FLOAT64,sampleRate, &bufferFrames, &mCallback, (void *)&rawData
try {
rt.openStream(&oParameters, &iParameters, RTAUDIO_SINT16, sampleRate, &nBufferFrames, &mCallback, (void*) &mAudio);
rt.startStream();
}
catch (RtAudioError& e) {
std::cout << e.getMessage() << std::endl;
return false;
}
return true;
It was so random when I was trying to playback my mic. I left input parameters and my wav file was suddenly playing. Is this is a bug?
I am trying to build an application that converts my old custom Ethernet logs (bin files) to standard winpcap style logs.
The problem is that I can't seem to find an example of how to opening a pcap_t* without using an adapter (network card). The temp.pkt has not been created.
I have looked thou the examples provided with Winpcap and all of them use a live adapter when dumping packets. This example is the closest \WpdPack\Examples-pcap\savedump\savedump.c is the closest, see example below slightly modified.
#ifdef _MSC_VER
/*
* we do not want the warnings about the old deprecated and unsecure CRT functions
* since these examples can be compiled under *nix as well
*/
#define _CRT_SECURE_NO_WARNINGS
#endif
#include "pcap.h"
int main(int argc, char **argv)
{
pcap_if_t *alldevs;
pcap_if_t *d;
int inum;
int i=0;
pcap_t *adhandle;
char errbuf[PCAP_ERRBUF_SIZE];
pcap_dumper_t *dumpfile;
/* Open the adapter */
if ((adhandle= pcap_open(??????, // name of the device
65536, // portion of the packet to capture.
// 65536 grants that the whole packet will be captured on all the MACs.
1, // promiscuous mode (nonzero means promiscuous)
1000, // read timeout
errbuf // error buffer
)) == NULL)
{
fprintf(stderr,"\nUnable to open the adapter. %s is not supported by WinPcap\n", d->name);
/* Free the device list */
pcap_freealldevs(alldevs);
return -1;
}
/* Open the dump file */
dumpfile = pcap_dump_open(adhandle, argv[1]);
if(dumpfile==NULL) {
fprintf(stderr,"\nError opening output file\n");
return -1;
}
// ---------------------------
struct pcap_pkthdr header;
header.ts.tv_sec = 1 ; /* seconds */
header.ts.tv_usec = 1; /* and microseconds */
header.caplen = 100; /* length of portion present */
header.len = 100 ; /* length this packet (off wire) */
u_char pkt_data[100];
for( int i = 0 ; i < 100 ; i++ ) {
pkt_data[i] = i ;
}
pcap_dump( (u_char *) dumpfile, &header, (u_char *) &pkt_data);
// ---------------------------
/* start the capture */
// pcap_loop(adhandle, 0, packet_handler, (unsigned char *)dumpfile);
pcap_close(adhandle);
return 0;
}
I suggest doing that using pcap_t since using WinPcap is better than writing it yourself.
The following steps is how to do it:
Use pcap_open_dead() function to create a pcap_t. Read the function description here. The linktype for Ethernet is 1.
Use pcap_dump_open() function to create a pcap_dumper_t.
Use pcap_dump() function to write the packet to the dump file.
I hope this would help you.
If all you're doing is converting your own file format to .pcap, you don't need a pcap_t*, you can just use something like:
FILE* create_pcap_file(const char *filename, int linktype)
{
struct pcap_file_header fh;
fh.magic = TCPDUMP_MAGIC;
fh.sigfigs = 0;
fh.version_major = 2;
fh.version_minor = 4;
fh.snaplen = 2<<15;
fh.thiszone = 0;
fh.linktype = linktype;
FILE *file = fopen(filename, "wb");
if(file != NULL) {
if(fwrite(&fh, sizeof(fh), 1, file) != 1) {
fclose(file);
file = NULL;
}
}
return file;
}
int write_pcap_packet(FILE* file,size_t length,const unsigned char *data,const struct timeval *tval)
{
struct pcap_pkthdr pkhdr;
pkhdr.caplen = length;
pkhdr.len = length;
pkhdr.ts = *tval;
if(fwrite(&pkhdr, sizeof(pkhdr), 1, file) != 1) {
return 1;
}
if(fwrite(data, 1, length, file) != length) {
return 2;
}
return 0;
}
So I have this problem.
I have an IplImage that i want to compress to JPEG and do something with it. I use libjpeg.
I found a lot of answers "read through examples and docs" and such and did that. And successfully written a function for that.
FILE* convert2jpeg(IplImage* frame)
{
FILE* outstream = NULL;
outstream=malloc(frame->imageSize*frame->nChannels*sizeof(char))
unsigned char *outdata = (uchar *) frame->imageData;
struct jpeg_error_mgr jerr;
struct jpeg_compress_struct cinfo;
int row_stride;
JSAMPROW row_ptr[1];
jpeg_create_compress(&cinfo);
jpeg_stdio_dest(&cinfo, outstream);
cinfo.image_width = frame->width;
cinfo.image_height = frame->height;
cinfo.input_components = frame->nChannels;
cinfo.in_color_space = JCS_RGB;
jpeg_set_defaults(&cinfo);
jpeg_start_compress(&cinfo, TRUE);
row_stride = frame->width * frame->nChannels;
while (cinfo.next_scanline < cinfo.image_height) {
row_ptr[0] = &outdata[cinfo.next_scanline * row_stride];
jpeg_write_scanlines(&cinfo, row_ptr, 1);
}
jpeg_finish_compress(&cinfo);
jpeg_destroy_compress(&cinfo);
return outstream;
}
Now this function is straight from the examples (except the part of allocating memory, but i need that since i'm not writnig to a file), but it still doesn't work.
It dies on jpeg_start_compress(&cinfo, TRUE); part?
Can anybody help?
I've been able to found a solution using the latest jpeglib available on their website.
New methods in : jpeg_mem_dest(&cinfo, outbuffer, outlen);
bool ipl2jpeg(IplImage *frame, unsigned char **outbuffer, long unsigned int *outlen) {
unsigned char *outdata = (uchar *) frame->imageData;
struct jpeg_compress_struct cinfo = {0};
struct jpeg_error_mgr jerr;
JSAMPROW row_ptr[1];
int row_stride;
*outbuffer = NULL;
*outlen = 0;
cinfo.err = jpeg_std_error(&jerr);
jpeg_create_compress(&cinfo);
jpeg_mem_dest(&cinfo, outbuffer, outlen);
cinfo.image_width = frame->width;
cinfo.image_height = frame->height;
cinfo.input_components = frame->nChannels;
cinfo.in_color_space = JCS_RGB;
jpeg_set_defaults(&cinfo);
jpeg_start_compress(&cinfo, TRUE);
row_stride = frame->width * frame->nChannels;
while (cinfo.next_scanline < cinfo.image_height) {
row_ptr[0] = &outdata[cinfo.next_scanline * row_stride];
jpeg_write_scanlines(&cinfo, row_ptr, 1);
}
jpeg_finish_compress(&cinfo);
jpeg_destroy_compress(&cinfo);
return true;
}
I got it to work using the following code for memory to memory compression.
#include <stdio.h>
#include "jpeg/jpeglib.h"
/*
This a custom destination manager for jpeglib that
enables the use of memory to memory compression.
See IJG documentation for details.
*/
typedef struct {
struct jpeg_destination_mgr pub; /* base class */
JOCTET* buffer; /* buffer start address */
int bufsize; /* size of buffer */
size_t datasize; /* final size of compressed data */
int* outsize; /* user pointer to datasize */
int errcount; /* counts up write errors due to
buffer overruns */
} memory_destination_mgr;
typedef memory_destination_mgr* mem_dest_ptr;
/* ------------------------------------------------------------- */
/* MEMORY DESTINATION INTERFACE METHODS */
/* ------------------------------------------------------------- */
/* This function is called by the library before any data gets written */
METHODDEF(void)
init_destination (j_compress_ptr cinfo)
{
mem_dest_ptr dest = (mem_dest_ptr)cinfo->dest;
dest->pub.next_output_byte = dest->buffer; /* set destination buffer */
dest->pub.free_in_buffer = dest->bufsize; /* input buffer size */
dest->datasize = 0; /* reset output size */
dest->errcount = 0; /* reset error count */
}
/* This function is called by the library if the buffer fills up
I just reset destination pointer and buffer size here.
Note that this behavior, while preventing seg faults
will lead to invalid output streams as data is over-
written.
*/
METHODDEF(boolean)
empty_output_buffer (j_compress_ptr cinfo)
{
mem_dest_ptr dest = (mem_dest_ptr)cinfo->dest;
dest->pub.next_output_byte = dest->buffer;
dest->pub.free_in_buffer = dest->bufsize;
++dest->errcount; /* need to increase error count */
return TRUE;
}
/* Usually the library wants to flush output here.
I will calculate output buffer size here.
Note that results become incorrect, once
empty_output_buffer was called.
This situation is notified by errcount.
*/
METHODDEF(void)
term_destination (j_compress_ptr cinfo)
{
mem_dest_ptr dest = (mem_dest_ptr)cinfo->dest;
dest->datasize = dest->bufsize - dest->pub.free_in_buffer;
if (dest->outsize) *dest->outsize += (int)dest->datasize;
}
/* Override the default destination manager initialization
provided by jpeglib. Since we want to use memory-to-memory
compression, we need to use our own destination manager.
*/
GLOBAL(void)
jpeg_memory_dest (j_compress_ptr cinfo, JOCTET* buffer, int bufsize, int* outsize)
{
mem_dest_ptr dest;
/* first call for this instance - need to setup */
if (cinfo->dest == 0) {
cinfo->dest = (struct jpeg_destination_mgr *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
sizeof (memory_destination_mgr));
}
dest = (mem_dest_ptr) cinfo->dest;
dest->bufsize = bufsize;
dest->buffer = buffer;
dest->outsize = outsize;
/* set method callbacks */
dest->pub.init_destination = init_destination;
dest->pub.empty_output_buffer = empty_output_buffer;
dest->pub.term_destination = term_destination;
}
/* ------------------------------------------------------------- */
/* MEMORY SOURCE INTERFACE METHODS */
/* ------------------------------------------------------------- */
/* Called before data is read */
METHODDEF(void)
init_source (j_decompress_ptr dinfo)
{
/* nothing to do here, really. I mean. I'm not lazy or something, but...
we're actually through here. */
}
/* Called if the decoder wants some bytes that we cannot provide... */
METHODDEF(boolean)
fill_input_buffer (j_decompress_ptr dinfo)
{
/* we can't do anything about this. This might happen if the provided
buffer is either invalid with regards to its content or just a to
small bufsize has been given. */
/* fail. */
return FALSE;
}
/* From IJG docs: "it's not clear that being smart is worth much trouble"
So I save myself some trouble by ignoring this bit.
*/
METHODDEF(void)
skip_input_data (j_decompress_ptr dinfo, INT32 num_bytes)
{
/* There might be more data to skip than available in buffer.
This clearly is an error, so screw this mess. */
if ((size_t)num_bytes > dinfo->src->bytes_in_buffer) {
dinfo->src->next_input_byte = 0; /* no buffer byte */
dinfo->src->bytes_in_buffer = 0; /* no input left */
} else {
dinfo->src->next_input_byte += num_bytes;
dinfo->src->bytes_in_buffer -= num_bytes;
}
}
/* Finished with decompression */
METHODDEF(void)
term_source (j_decompress_ptr dinfo)
{
/* Again. Absolute laziness. Nothing to do here. Boring. */
}
GLOBAL(void)
jpeg_memory_src (j_decompress_ptr dinfo, unsigned char* buffer, size_t size)
{
struct jpeg_source_mgr* src;
/* first call for this instance - need to setup */
if (dinfo->src == 0) {
dinfo->src = (struct jpeg_source_mgr *)
(*dinfo->mem->alloc_small) ((j_common_ptr) dinfo, JPOOL_PERMANENT,
sizeof (struct jpeg_source_mgr));
}
src = dinfo->src;
src->next_input_byte = buffer;
src->bytes_in_buffer = size;
src->init_source = init_source;
src->fill_input_buffer = fill_input_buffer;
src->skip_input_data = skip_input_data;
src->term_source = term_source;
/* IJG recommend to use their function - as I don't know ****
about how to do better, I follow this recommendation */
src->resync_to_restart = jpeg_resync_to_restart;
}
And in your main compression function replace the jpeg_stdio_dest with
int numBytes = 0; //size of jpeg after compression
char * storage = new char[150000]; //storage buffer
JOCTET *jpgbuff = (JOCTET*)storage; //JOCTET pointer to buffer
jpeg_memory_dest(&cinfo,jpgbuff,150000,&numBytes);
The 150000 is a static size buffer, you probably will have images that will exceed it, so allocate accordingly.
I got in-memory compression to work. See the following
#define OUTPUT_BUF_SIZE 4096 /* choose an efficiently fwrite’able size */
/* Expanded data destination object for memory output */
typedef struct {
struct jpeg_destination_mgr pub; /* public fields */
unsigned char ** outbuffer; /* target buffer */
unsigned long * outsize;
unsigned char * newbuffer; /* newly allocated buffer */
JOCTET * buffer; /* start of buffer */
size_t bufsize;
} my_mem_destination_mgr;
typedef my_mem_destination_mgr * my_mem_dest_ptr;
void
init_mem_destination (j_compress_ptr cinfo)
{
/* no work necessary here */
}
boolean
empty_mem_output_buffer (j_compress_ptr cinfo)
{
size_t nextsize;
JOCTET * nextbuffer;
my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
/* Try to allocate new buffer with double size */
nextsize = dest->bufsize * 2;
nextbuffer = (JOCTET *)malloc(nextsize);
if (nextbuffer == NULL)
ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
memcpy(nextbuffer, dest->buffer, dest->bufsize);
if (dest->newbuffer != NULL)
free(dest->newbuffer);
dest->newbuffer = nextbuffer;
dest->pub.next_output_byte = nextbuffer + dest->bufsize;
dest->pub.free_in_buffer = dest->bufsize;
dest->buffer = nextbuffer;
dest->bufsize = nextsize;
return TRUE;
}
void
term_mem_destination (j_compress_ptr cinfo)
{
my_mem_dest_ptr dest = (my_mem_dest_ptr) cinfo->dest;
*dest->outbuffer = dest->buffer;
*dest->outsize = dest->bufsize – dest->pub.free_in_buffer;
}
void
jpeg_mem_dest (j_compress_ptr cinfo,
unsigned char ** outbuffer, unsigned long * outsize)
{
my_mem_dest_ptr dest;
if (outbuffer == NULL || outsize == NULL) /* sanity check */
ERREXIT(cinfo, JERR_BUFFER_SIZE);
/* The destination object is made permanent so that multiple JPEG images
* can be written to the same buffer without re-executing jpeg_mem_dest.
*/
if (cinfo->dest == NULL) { /* first time for this JPEG object? */
cinfo->dest = (struct jpeg_destination_mgr *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_PERMANENT,
sizeof(my_mem_destination_mgr));
}
dest = (my_mem_dest_ptr) cinfo->dest;
dest->pub.init_destination = init_mem_destination;
dest->pub.empty_output_buffer = empty_mem_output_buffer;
dest->pub.term_destination = term_mem_destination;
dest->outbuffer = outbuffer;
dest->outsize = outsize;
dest->newbuffer = NULL;
if (*outbuffer == NULL || *outsize == 0) {
/* Allocate initial buffer */
dest->newbuffer = *outbuffer = (unsigned char*)malloc(OUTPUT_BUF_SIZE);
if (dest->newbuffer == NULL)
ERREXIT1(cinfo, JERR_OUT_OF_MEMORY, 10);
*outsize = OUTPUT_BUF_SIZE;
}
dest->pub.next_output_byte = dest->buffer = *outbuffer;
dest->pub.free_in_buffer = dest->bufsize = *outsize;
}
//*******************************************************************************************
To use this do something like this in the main
/************/
unsigned long outlen;
unsigned char *outbuffer;
jpeg_mem_dest (&cinfo,&outbuffer,&outlen );
printf(“outlen is %lu\n”,(long unsigned int)outlen);
After fighting with libJpeg for 2 days (pointers, memory stepping, and pulling hair) I gave up and used the all favourite save-to-disk-load-to-memory approach, so if anybody is interested here is the method:
char* convert2jpeg(IplImage* frame, int* frame_size) {
FILE* infile = NULL;
struct stat fileinfo_buf;
if (cvSaveImage(name_buf, frame) < 0) {
printf("\nCan't save image %s", name_buf);
return NULL;
}
if (stat(name_buf, &fileinfo_buf) < 0) {
printf("\nPLAYER [convert2jpeg] stat");
return NULL;
}
*frame_size = fileinfo_buf.st_size;
char* buffer = (char *) malloc(fileinfo_buf.st_size + 1);
if ((infile = fopen(name_buf, "rb")) == NULL) {
printf("\nPLAYER [convert2jpeg] fopen %s", name_buf);
free(buffer);
return NULL;
}
fread(buffer, fileinfo_buf.st_size, 1, infile);
fclose(infile);
return buffer;
}
I hope somebody finds this usefull. I wish somebody from OpenCV developers sees this thread and implements direct to buffer JPEG conversion in OpenCV and spares us the misery and 1 save/load to disk operation.