记录下初始化方法，当时作的一些注释：html
- (void)initCompressionSession{
if(compressionSession){
VTCompressionSessionCompleteFrames(compressionSession, kCMTimeInvalid);
VTCompressionSessionInvalidate(compressionSession);
CFRelease(compressionSession);
compressionSession = NULL;
}
OSStatus status = VTCompressionSessionCreate(NULL, _configuration.videoSize.width, _configuration.videoSize.height, kCMVideoCodecType_H264, NULL, NULL, NULL, VideoCompressonOutputCallback, (__bridge void *)self, &compressionSession);
if(status != noErr){
return;
}
/************************************视频会议客户端间视频交互*****************************************
*手机视频硬编码上传视频数据到html5视频会议客户端,html5视频会议客户端显示不了手机上传的视频画面而详释.
*为了html5视频会议客户端显示手机上传的视频画面，特选用BP-Baseline Profile且只支持CAVLC.BP-Baseline Profile选用CABAC导
*致接收端马赛克严重.
*
*BP-Baseline Profile:基本画质.支持 I/P 帧,只支持无交错(Progressive)和CAVLC.
*EP-Extended profile:进阶画质.支持 I/P/B/SP/SI 帧,只支持无交错(Progressive)和CAVLC.
*MP-Main profile:主流画质.提供 I/P/B 帧,支持无交错(Progressive)和交错(Interlaced),也支持CAVLC和CABAC.
*HP-High profile:高级画质.在main Profile的基础上增长了8x8内部预测、自定义量化、无损视频编码和更多的YUV格式.
*/
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_MaxKeyFrameInterval,(__bridge CFTypeRef)@(_configuration.videoMaxKeyframeInterval));
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_MaxKeyFrameIntervalDuration,(__bridge CFTypeRef)@(_configuration.videoMaxKeyframeInterval));
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_AverageBitRate, (__bridge CFTypeRef)@(_configuration.videoBitRate));
NSArray *limit = @[@(_configuration.videoBitRate * 1.5/8),@(1)];
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_DataRateLimits, (__bridge CFArrayRef)limit);
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_ExpectedFrameRate, (__bridge CFTypeRef)@(_configuration.videoFrameRate));
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_RealTime, kCFBooleanFalse);
//status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_ProfileLevel, kVTProfileLevel_H264_Main_AutoLevel);
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_ProfileLevel, kVTProfileLevel_H264_Baseline_AutoLevel);
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_AllowFrameReordering, kCFBooleanFalse);
//status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_H264EntropyMode, kVTH264EntropyMode_CABAC);
status = VTSessionSetProperty(compressionSession, kVTCompressionPropertyKey_H264EntropyMode, kVTH264EntropyMode_CAVLC);
VTCompressionSessionPrepareToEncodeFrames(compressionSession);
}
static void VideoCompressonOutputCallback(void *VTref, void *VTFrameRef, OSStatus status, VTEncodeInfoFlags infoFlags, CMSampleBufferRef sampleBuffer)
{
if(!sampleBuffer) return;
CFArrayRef array = CMSampleBufferGetSampleAttachmentsArray(sampleBuffer, true);
if(!array) return;
CFDictionaryRef dic = (CFDictionaryRef)CFArrayGetValueAtIndex(array, 0);
if(!dic) return;
BOOL keyframe = !CFDictionaryContainsKey(dic, kCMSampleAttachmentKey_NotSync);
uint64_t timeStamp = [((__bridge_transfer NSNumber*)VTFrameRef) longLongValue];
LMHardwareVideoEncoder *videoEncoder = (__bridge LMHardwareVideoEncoder *)VTref;
if(status != noErr){
return;
}
if (keyframe && !videoEncoder->sps)
{
CMFormatDescriptionRef format = CMSampleBufferGetFormatDescription(sampleBuffer);
size_t sparameterSetSize, sparameterSetCount;
const uint8_t *sparameterSet;
OSStatus statusCode = CMVideoFormatDescriptionGetH264ParameterSetAtIndex(format, 0, &sparameterSet, &sparameterSetSize, &sparameterSetCount, 0 );
if (statusCode == noErr)
{
size_t pparameterSetSize, pparameterSetCount;
const uint8_t *pparameterSet;
OSStatus statusCode = CMVideoFormatDescriptionGetH264ParameterSetAtIndex(format, 1, &pparameterSet, &pparameterSetSize, &pparameterSetCount, 0 );
if (statusCode == noErr)
{
videoEncoder->sps = [NSData dataWithBytes:sparameterSet length:sparameterSetSize];
videoEncoder->pps = [NSData dataWithBytes:pparameterSet length:pparameterSetSize];
}
}
}
CMBlockBufferRef dataBuffer = CMSampleBufferGetDataBuffer(sampleBuffer);
size_t length, totalLength;
char *dataPointer;
OSStatus statusCodeRet = CMBlockBufferGetDataPointer(dataBuffer, 0, &length, &totalLength, &dataPointer);
if (statusCodeRet == noErr) {
size_t bufferOffset = 0;
static const int AVCCHeaderLength = 4;
while (bufferOffset < totalLength - AVCCHeaderLength) {
// Read the NAL unit length
uint32_t NALUnitLength = 0;
memcpy(&NALUnitLength, dataPointer + bufferOffset, AVCCHeaderLength);
NALUnitLength = CFSwapInt32BigToHost(NALUnitLength);
NSData *videoFrameData = [[NSData alloc] initWithBytes:(dataPointer + bufferOffset + AVCCHeaderLength) length:NALUnitLength];
NSData *spsData = videoEncoder->sps;
NSData *ppsData = videoEncoder->pps;
NSDictionary *videoFrameDict = nil;
if (videoFrameData || videoEncoder->sps || videoEncoder -> pps) {
if (keyframe) {
/*
*C语言开内存空间
*/
/*
unsigned char *body = NULL;
int iIndex = 0;
NSInteger bodyLength = 30241;
const char *sps = (const char *)spsData.bytes;
NSInteger spsLength = spsData.length;
const char *pps = (const char *)ppsData.bytes;
NSInteger ppsLength = ppsData.length;
const char *videoData = (const char *)videoFrameData.bytes;
NSInteger videoDataLength = videoFrameData.length;
body = (unsigned char *)malloc(bodyLength);
memset(body, 0, bodyLength);
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x01;
memcpy(body + iIndex, sps, spsLength);
iIndex += spsLength;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x01;
memcpy(body + iIndex, pps, ppsLength);
iIndex += ppsLength;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x01;
memcpy(body + iIndex, videoData, videoDataLength);
iIndex += videoDataLength;
NSData *currentData = [NSData dataWithBytes:body length:iIndex];
videoFrameDict = [NSDictionary dictionaryWithObjectsAndKeys:currentData, @"currentVideoData", [NSNumber numberWithInteger:iIndex], @"currentVideoDataLength", [NSNumber numberWithInteger:1], @"isVideoKeyFrame", nil];
free(body);
*/
const char headerBytes[] = "\x00\x00\x00\x01";
size_t headerBytesLength = sizeof(headerBytes) - 1;
NSData *headerBytesData = [NSData dataWithBytes:headerBytes length:headerBytesLength];
NSMutableData *assemblyMutableData = [[NSMutableData alloc] init];
[assemblyMutableData appendData:headerBytesData];
[assemblyMutableData appendData:spsData];
[assemblyMutableData appendData:headerBytesData];
[assemblyMutableData appendData:ppsData];
[assemblyMutableData appendData:headerBytesData];
[assemblyMutableData appendData:videoFrameData];
NSData *assemblyData = [NSData dataWithData:assemblyMutableData];
videoFrameDict = [NSDictionary dictionaryWithObjectsAndKeys:assemblyData, @"currentVideoData", [NSNumber numberWithInteger:assemblyData.length], @"currentVideoDataLength", [NSNumber numberWithInteger:1], @"isVideoKeyFrame", nil];
}
else {
/*
*C语言开内存空间
*/
/*
int iIndex = 0;
NSInteger videoLength = videoFrameData.length + 9;
unsigned char *body = (unsigned char *)malloc(videoLength);
memset(body, 0, videoLength);
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x00;
body[iIndex ++] = 0x01;
memcpy(body + iIndex, videoFrameData.bytes, videoFrameData.length);
iIndex += videoFrameData.length;
NSData *currentData = [NSData dataWithBytes:body length:iIndex];
videoFrameDict = [NSDictionary dictionaryWithObjectsAndKeys:currentData, @"currentVideoData", [NSNumber numberWithInteger:iIndex], @"currentVideoDataLength", [NSNumber numberWithInteger:0], @"isVideoKeyFrame", nil];
free(body);
*/
const char headerBytes[] = "\x00\x00\x00\x01";
size_t headerBytesLength = sizeof(headerBytes) - 1;
NSData *headerBytesData = [NSData dataWithBytes:headerBytes length:headerBytesLength];
NSMutableData *assemblyMutableData = [[NSMutableData alloc] init];
[assemblyMutableData appendData:headerBytesData];
[assemblyMutableData appendData:videoFrameData];
NSData *assemblyData = [NSData dataWithData:assemblyMutableData];
videoFrameDict = [NSDictionary dictionaryWithObjectsAndKeys:assemblyData, @"currentVideoData", [NSNumber numberWithInteger:assemblyData.length], @"currentVideoDataLength", [NSNumber numberWithInteger:0], @"isVideoKeyFrame", nil];
}
}
// LMVideoFrame *videoFrame = [LMVideoFrame new];
// videoFrame.timestamp = timeStamp;
// videoFrame.data = [[NSData alloc] initWithBytes:(dataPointer + bufferOffset + AVCCHeaderLength) length:NALUnitLength];
// videoFrame.isKeyFrame = keyframe;
// videoFrame.sps = videoEncoder->sps;
// videoFrame.pps = videoEncoder->pps;
//
// if(videoEncoder.h264Delegate && [videoEncoder.h264Delegate respondsToSelector:@selector(videoEncoder:videoFrame:)]) {
// [videoEncoder.h264Delegate videoEncoder:videoEncoder videoFrame:videoFrame];
// }
if(videoEncoder.h264Delegate && [videoEncoder.h264Delegate respondsToSelector:@selector(videoEncoder:videoFrameDict:)]) {
[videoEncoder.h264Delegate videoEncoder:videoEncoder videoFrameDict:videoFrameDict];
}
bufferOffset += AVCCHeaderLength + NALUnitLength;
}
}
}
推荐个很全面的音视频工程：点击打开连接html5