我想通过http流式传输视频，我正在使用ogg（theora + vorbis），现在我有发送器和接收器，我可以使用命令行运行它们：
发信人：
ffmpeg -f video4linux2 -s 320x240 -i /dev/mycam -codec:v libtheora -qscale:v 5 -f ogg http://127.0.0.1:8080
接收器：
sudo gst-launch-0.10 tcpserversrc port = 8080 ! oggdemux ! theoradec ! autovideosink
现在，发送者同时发送音频和视频，但接收者只播放视频。
它完美无缺，但现在我不想使用ffmpeg而只使用libav *。
这是我的流媒体课程：
class VCORE_LIBRARY_EXPORT VVideoWriter : private boost::noncopyable
{
public:
VVideoWriter( );
~VVideoWriter( );
bool openFile( const std::string& name,
int fps, int videoBitrate, int width, int height,
int audioSampleRate, bool stereo, int audioBitrate );
void close( );
bool writeVideoFrame( const uint8_t* image, int64_t timestamp );
bool writeAudioFrame( const int16_t* data, int64_t timestamp );
int audioFrameSize( ) const;
private:
AVFrame *m_videoFrame;
AVFrame *m_audioFrame;
AVFormatContext *m_context;
AVStream *m_videoStream;
AVStream *m_audioStream;
int64_t m_startTime;
};
初始化：
bool VVideoWriter::openFile( const std::string& name,
int fps, int videoBitrate, int width, int height,
int audioSampleRate, bool stereo, int audioBitrate )
{
if( ! m_context )
{
// initalize the AV context
m_context = avformat_alloc_context( );
assert( m_context );
// get the output format
m_context->oformat = av_guess_format( "ogg", name.c_str( ), nullptr );
if( m_context->oformat )
{
strcpy( m_context->filename, name.c_str( ) );
auto codecID = AV_CODEC_ID_THEORA;
auto codec = avcodec_find_encoder( codecID );
if( codec )
{
m_videoStream = avformat_new_stream( m_context, codec );
assert( m_videoStream );
// initalize codec
auto codecContext = m_videoStream->codec;
bool globalHeader = m_context->oformat->flags & AVFMT_GLOBALHEADER;
if( globalHeader )
codecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;
codecContext->codec_id = codecID;
codecContext->codec_type = AVMEDIA_TYPE_VIDEO;
codecContext->width = width;
codecContext->height = height;
codecContext->time_base.den = fps;
codecContext->time_base.num = 1;
codecContext->bit_rate = videoBitrate;
codecContext->pix_fmt = PIX_FMT_YUV420P;
codecContext->flags |= CODEC_FLAG_QSCALE;
codecContext->global_quality = FF_QP2LAMBDA * 5;
int res = avcodec_open2( codecContext, codec, nullptr );
if( res >= 0 )
{
auto codecID = AV_CODEC_ID_VORBIS;
auto codec = avcodec_find_encoder( codecID );
if( codec )
{
m_audioStream = avformat_new_stream( m_context, codec );
assert( m_audioStream );
// initalize codec
auto codecContext = m_audioStream->codec;
bool globalHeader = m_context->oformat->flags & AVFMT_GLOBALHEADER;
if( globalHeader )
codecContext->flags |= CODEC_FLAG_GLOBAL_HEADER;
codecContext->codec_id = codecID;
codecContext->codec_type = AVMEDIA_TYPE_AUDIO;
codecContext->sample_fmt = AV_SAMPLE_FMT_FLTP;
codecContext->bit_rate = audioBitrate;
codecContext->sample_rate = audioSampleRate;
codecContext->channels = stereo ? 2 : 1;
codecContext->channel_layout = stereo ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
res = avcodec_open2( codecContext, codec, nullptr );
if( res >= 0 )
{
// try to open the file
if( avio_open( &m_context->pb, m_context->filename, AVIO_FLAG_WRITE ) >= 0 )
{
m_audioFrame->nb_samples = codecContext->frame_size;
m_audioFrame->format = codecContext->sample_fmt;
m_audioFrame->channel_layout = codecContext->channel_layout;
boost::posix_time::ptime time_t_epoch( boost::gregorian::date( 1970, 1, 1 ) );
m_context->start_time_realtime = ( boost::posix_time::microsec_clock::universal_time( ) - time_t_epoch ).total_microseconds( );
m_startTime = -1;
// write the header
if( avformat_write_header( m_context, nullptr ) >= 0 )
{
return true;
}
else std::cerr << "VVideoWriter: failed to write video header" << std::endl;
}
else std::cerr << "VVideoWriter: failed to open video file " << name << std::endl;
}
else std::cerr << "VVideoWriter: failed to initialize audio codec" << std::endl;
}
else std::cerr << "VVideoWriter: requested audio codec is not supported" << std::endl;
}
else std::cerr << "VVideoWriter: failed to initialize video codec" << std::endl;
}
else std::cerr << "VVideoWriter: requested video codec is not supported" << std::endl;
}
else std::cerr << "VVideoWriter: requested video format is not supported" << std::endl;
avformat_free_context( m_context );
m_context = nullptr;
m_videoStream = nullptr;
m_audioStream = nullptr;
}
return false;
}
撰写视频：
bool VVideoWriter::writeVideoFrame( const uint8_t* image, int64_t timestamp )
{
if( m_context ) {
auto codecContext = m_videoStream->codec;
avpicture_fill( reinterpret_cast<AVPicture*>( m_videoFrame ),
const_cast<uint8_t*>( image ),
codecContext->pix_fmt, codecContext->width, codecContext->height );
AVPacket pkt;
av_init_packet( & pkt );
pkt.data = nullptr;
pkt.size = 0;
int gotPacket = 0;
if( ! avcodec_encode_video2( codecContext, &pkt, m_videoFrame, & gotPacket ) ) {
if( gotPacket == 1 ) {
pkt.stream_index = m_videoStream->index;
int res;
{
pkt.pts = AV_NOPTS_VALUE;
pkt.dts = AV_NOPTS_VALUE;
pkt.stream_index = m_videoStream->index;
res = av_write_frame( m_context, &pkt );
}
av_free_packet( & pkt );
return res >= 0;
}
assert( ! pkt.size );
return true;
}
}
return false;
}
写音频（现在我写测试虚拟音频）：
bool VVideoWriter::writeAudioFrame( const int16_t* data, int64_t timestamp )
{
if( m_context ) {
auto codecContext = m_audioStream->codec;
int buffer_size = av_samples_get_buffer_size(nullptr, codecContext->channels, codecContext->frame_size, codecContext->sample_fmt, 0);
float *samples = (float*)av_malloc(buffer_size);
for (int i = 0; i < buffer_size / sizeof(float); i++)
samples[i] = 1000. * sin((double)i/2.);
int ret = avcodec_fill_audio_frame( m_audioFrame, codecContext->channels, codecContext->sample_fmt, (const uint8_t*)samples, buffer_size, 0);
assert( ret >= 0 );
(void)(ret);
AVPacket pkt;
av_init_packet( & pkt );
pkt.data = nullptr;
pkt.size = 0;
int gotPacket = 0;
if( ! avcodec_encode_audio2( codecContext, &pkt, m_audioFrame, & gotPacket ) ) {
if( gotPacket == 1 ) {
pkt.stream_index = m_audioStream->index;
int res;
{
pkt.pts = AV_NOPTS_VALUE;
pkt.dts = AV_NOPTS_VALUE;
pkt.stream_index = m_audioStream->index;
res = av_write_frame( m_context, &pkt );
}
av_free_packet( & pkt );
return res >= 0;
}
assert( ! pkt.size );
return true;
}
return false;
}
return false;
}
这是测试示例（我从网络摄像头和虚拟音频发送视频）：
class TestVVideoWriter : public sigslot::has_slots<>
{
public:
TestVVideoWriter( ) :
m_fileOpened( false )
{
}
void onCapturedFrame( cricket::VideoCapturer*, const cricket::CapturedFrame* capturedFrame )
{
if( m_fileOpened ) {
m_writer.writeVideoFrame( reinterpret_cast<const uint8_t*>( capturedFrame->data ),
capturedFrame->time_stamp / 1000 );
m_writer.writeAudioFrame( nullptr , 0 );
} else {
m_fileOpened = m_writer.openFile( "http://127.0.0.1:8080",
15, 40000, capturedFrame->width, capturedFrame->height,
16000, false, 64000 );
}
}
public:
vcore::VVideoWriter m_writer;
bool m_fileOpened;
};
TestVVideoWriter testWriter;
BOOST_AUTO_TEST_SUITE(TEST_VIDEO_WRITER)
BOOST_AUTO_TEST_CASE(testWritingVideo)
{
cricket::LinuxDeviceManager deviceManager;
std::vector<cricket::Device> devs;
if( deviceManager.GetVideoCaptureDevices( &devs ) ) {
if( devs.size( ) ) {
boost::shared_ptr<cricket::VideoCapturer> camera( deviceManager.CreateVideoCapturer( devs[ 0 ] ) );
if( camera ) {
cricket::VideoFormat format( 320, 240, cricket::VideoFormat::FpsToInterval( 30 ),
camera->GetSupportedFormats( )->front( ).fourcc );
cricket::VideoFormat best;
if( camera->GetBestCaptureFormat( format, &best ) ) {
camera->SignalFrameCaptured.connect( &testWriter, &TestVVideoWriter::onCapturedFrame );
if( camera->Start( best ) != cricket::CS_FAILED ) {
boost::this_thread::sleep( boost::posix_time::seconds( 10 ) );
return;
}
}
}
}
}
std::cerr << "Problem has occured with camera" << std::endl;
}
BOOST_AUTO_TEST_SUITE_END() // TEST_VIDEO_WRITER
但是，在这种情况下，gstreamer只在我的测试程序停止执行时开始播放视频（在这种情况下10秒后）。它不适合我，我希望gstreamer在开始我的测试程序后立即开始播放。
有人可以帮助我吗？
P.S。抱歉我的英文。
答案 0 :(得分：0)
最后，我得到了答案：我没有在音频帧中写pts和dts。