func NewSwrCtx(options []*Option, cc *CodecCtx) *SwrCtx { this := &SwrCtx{swrCtx: C.swr_alloc(), cc: cc} for _, option := range options { option.Set(this.swrCtx) } if int(C.swr_init(this.swrCtx)) < 0 { return nil } return this }
func (self *Decoder) Start(videoStream, audioStream *C.AVStream, scaleWidth, scaleHeight C.int) *Decoder { self.running = true self.duration = time.Duration(self.FormatContext.duration * C.AV_TIME_BASE / 1000) vCodecCtx := videoStream.codec aCodecCtx := audioStream.codec self.durationPerSample = time.Second / time.Duration(aCodecCtx.sample_rate) // frame pool poolSize := 16 pool := make(chan *C.AVFrame, poolSize) self.pool = pool numBytes := C.size_t(C.avpicture_get_size(C.PIX_FMT_YUV420P, scaleWidth, scaleHeight)) for i := 0; i < poolSize; i++ { frame := C.av_frame_alloc() self.frames = append(self.frames, frame) buffer := (*C.uint8_t)(unsafe.Pointer(C.av_malloc(numBytes))) self.buffers = append(self.buffers, buffer) C.avpicture_fill((*C.AVPicture)(unsafe.Pointer(frame)), buffer, C.PIX_FMT_YUV420P, scaleWidth, scaleHeight) pool <- frame } // decode self.frameChan = make(chan *C.AVFrame, 512) go func() { runtime.LockOSThread() // scale context scaleContext := C.sws_getCachedContext(nil, vCodecCtx.width, vCodecCtx.height, vCodecCtx.pix_fmt, scaleWidth, scaleHeight, C.PIX_FMT_YUV420P, C.SWS_LANCZOS, nil, nil, nil) if scaleContext == nil { log.Fatal("get scale context failed") } // resample context resampleContext := C.swr_alloc_set_opts(nil, C.AV_CH_LAYOUT_STEREO, C.AV_SAMPLE_FMT_FLT, aCodecCtx.sample_rate, C.int64_t(aCodecCtx.channel_layout), aCodecCtx.sample_fmt, aCodecCtx.sample_rate, 0, nil) if resampleContext == nil { log.Fatal("get resample context failed") } C.swr_init(resampleContext) var packet C.AVPacket var frameFinished C.int var pts int64 var packetTime time.Duration vFrame := C.av_frame_alloc() aFrame := C.av_frame_alloc() videoIndex := videoStream.index audioIndex := audioStream.index resampleBuffer := (*C.uint8_t)(C.av_malloc(4096 * 8)) resampleBufferp := &resampleBuffer self.Timer = NewTimer() // decode for self.running { // seek if self.seekTarget > 0 { if C.av_seek_frame(self.FormatContext, -1, C.int64_t(float64(self.seekNext)/float64(time.Second)*float64(C.AV_TIME_BASE)), C.AVSEEK_FLAG_BACKWARD) < 0 { log.Fatal("seek error") } for _, codecCtx := range self.openedCodecs { C.avcodec_flush_buffers(codecCtx) } p("frame seek done\n") } read_packet: // read packet C.av_free_packet(&packet) if C.av_read_frame(self.FormatContext, &packet) < 0 { // read packet log.Fatal("read frame error") //TODO stop gracefully } // get packet time if packet.dts != C.AV_NOPTS_VALUE { pts = int64(packet.dts) } else { pts = 0 } if packet.stream_index == videoIndex { packetTime = time.Duration(float64(pts) * float64(C.av_q2d(videoStream.time_base)) * float64(time.Second)) } else if packet.stream_index == audioIndex { packetTime = time.Duration(float64(pts) * float64(C.av_q2d(audioStream.time_base)) * float64(time.Second)) } else { // ignore packet goto read_packet } p("packet time %v at timer time %v\n", packetTime, self.Timer.Now()) // check seek if self.seekTarget > 0 && packetTime > 0 { // if packet time cannot determined, skip if packetTime < self.seekTarget { // seek again self.seekNext += self.seekStep p("seek again %v\n", self.seekNext) } else { // seek ok p("seek ok\n") self.seekTarget = 0 self.Timer.Jump(packetTime - self.Timer.Now()) } } // decode if packet.stream_index == videoIndex { // decode video if C.avcodec_decode_video2(vCodecCtx, vFrame, &frameFinished, &packet) < 0 { continue // bad packet } if frameFinished <= 0 { goto read_packet // frame not complete } bufFrame := <-pool // get frame buffer C.sws_scale(scaleContext, // scale &vFrame.data[0], &vFrame.linesize[0], 0, vCodecCtx.height, &bufFrame.data[0], &bufFrame.linesize[0]) bufFrame.pts = C.int64_t(packetTime) // set packet time self.frameChan <- bufFrame // push to queue p("video frame %v\n", packetTime) } else if packet.stream_index == audioIndex { // decode audio decode_audio_packet: l := C.avcodec_decode_audio4(aCodecCtx, aFrame, &frameFinished, &packet) if l < 0 { continue // bad packet } if frameFinished <= 0 { goto read_packet // frame not complete } if frameFinished > 0 { // frame finished n := C.swr_convert(resampleContext, resampleBufferp, 4096, aFrame.extended_data, aFrame.nb_samples) if n != aFrame.nb_samples { log.Fatal("audio resample failed") } self.audioFrames <- &AudioFrame{ time: packetTime, data: C.GoBytes(unsafe.Pointer(resampleBuffer), n*8), } } if l != packet.size { // multiple frame packet packet.size -= l packet.data = (*C.uint8_t)(unsafe.Pointer(uintptr(unsafe.Pointer(packet.data)) + uintptr(l))) goto decode_audio_packet } p("audio frame %v\n", packetTime) } else { // other stream goto read_packet } } }() // sync video go func() { maxDelta := (time.Second / time.Duration(C.av_q2d(videoStream.r_frame_rate)/10)) for frame := range self.frameChan { delta := time.Duration(frame.pts) - self.Timer.Now() p("video frame %v, delta %v, max delta %v\n", time.Duration(frame.pts), delta, maxDelta) if delta > 0 { if delta > maxDelta { self.Timer.Jump(delta) print("timer jumped\n") } else { time.Sleep(delta) } } else if delta < 0 { // drop frame self.RecycleFrame(frame) continue } self.timedFrames <- frame } }() return self }
//int swr_init (struct SwrContext *s) //Initialize context after user parameters have been set. func Swr_init(s *SwrContext) int { return int(C.swr_init((*C.struct_SwrContext)(s))) }
//Initialize context after user parameters have been set. func (s *Context) SwrInit() int { return int(C.swr_init((*C.struct_SwrContext)(s))) }