[英]Append audio samples to AVAssetWriter from streaming
从摄像机录制视频时,我正在使用一个项目,但音频来自流媒体。 音频帧显然与视频帧不同步。 如果我在没有视频的情况下使用AVAssetWriter,则通过流录制音频帧效果很好。 但是,如果我添加视频和音频帧,则听不到任何声音。
这是将音频数据从流转换为CMsampleBuffer的方法
AudioStreamBasicDescription monoStreamFormat = [self getAudioDescription];
CMFormatDescriptionRef format = NULL;
OSStatus status = CMAudioFormatDescriptionCreate(kCFAllocatorDefault, &monoStreamFormat, 0,NULL, 0, NULL, NULL, &format);
if (status != noErr) {
// really shouldn't happen
return nil;
}
CMSampleTimingInfo timing = { CMTimeMake(1, 44100.0), kCMTimeZero, kCMTimeInvalid };
CMSampleBufferRef sampleBuffer = NULL;
status = CMSampleBufferCreate(kCFAllocatorDefault, NULL, false, NULL, NULL, format, numSamples, 1, &timing, 0, NULL, &sampleBuffer);
if (status != noErr) {
// couldn't create the sample alguiebuffer
NSLog(@"Failed to create sample buffer");
CFRelease(format);
return nil;
}
// add the samples to the buffer
status = CMSampleBufferSetDataBufferFromAudioBufferList(sampleBuffer,
kCFAllocatorDefault,
kCFAllocatorDefault,
0,
samples);
if (status != noErr) {
NSLog(@"Failed to add samples to sample buffer");
CFRelease(sampleBuffer);
CFRelease(format);
return nil;
}
我不知道这是否与时间有关。 但是我想附加视频第一秒的音频帧。
有可能吗?
谢谢
最后我做到了
uint64_t _hostTimeToNSFactor = hostTime;
_hostTimeToNSFactor *= info.numer;
_hostTimeToNSFactor /= info.denom;
uint64_t timeNS = (uint64_t)(hostTime * _hostTimeToNSFactor);
CMTime presentationTime = self.initialiseTime;//CMTimeMake(timeNS, 1000000000);
CMSampleTimingInfo timing = { CMTimeMake(1, 44100), presentationTime, kCMTimeInvalid };
声明:本站的技术帖子网页,遵循CC BY-SA 4.0协议,如果您需要转载,请注明本站网址或者原文地址。任何问题请咨询:yoyou2525@163.com.