rename 'read' into 'play', 'publish' into 'record' (#463)

examples/client-play-format-h265/h265_decoder.go

@@ -0,0 +1,140 @@
+package main
+
+import (
+	"fmt"
+	"image"
+	"unsafe"
+)
+
+// #cgo pkg-config: libavcodec libavutil libswscale
+// #include <libavcodec/avcodec.h>
+// #include <libavutil/imgutils.h>
+// #include <libswscale/swscale.h>
+import "C"
+
+func frameData(frame *C.AVFrame) **C.uint8_t {
+	return (**C.uint8_t)(unsafe.Pointer(&frame.data[0]))
+}
+
+func frameLineSize(frame *C.AVFrame) *C.int {
+	return (*C.int)(unsafe.Pointer(&frame.linesize[0]))
+}
+
+// h265Decoder is a wrapper around FFmpeg's H265 decoder.
+type h265Decoder struct {
+	codecCtx    *C.AVCodecContext
+	srcFrame    *C.AVFrame
+	swsCtx      *C.struct_SwsContext
+	dstFrame    *C.AVFrame
+	dstFramePtr []uint8
+}
+
+// newH265Decoder allocates a new h265Decoder.
+func newH265Decoder() (*h265Decoder, error) {
+	codec := C.avcodec_find_decoder(C.AV_CODEC_ID_H265)
+	if codec == nil {
+		return nil, fmt.Errorf("avcodec_find_decoder() failed")
+	}
+
+	codecCtx := C.avcodec_alloc_context3(codec)
+	if codecCtx == nil {
+		return nil, fmt.Errorf("avcodec_alloc_context3() failed")
+	}
+
+	res := C.avcodec_open2(codecCtx, codec, nil)
+	if res < 0 {
+		C.avcodec_close(codecCtx)
+		return nil, fmt.Errorf("avcodec_open2() failed")
+	}
+
+	srcFrame := C.av_frame_alloc()
+	if srcFrame == nil {
+		C.avcodec_close(codecCtx)
+		return nil, fmt.Errorf("av_frame_alloc() failed")
+	}
+
+	return &h265Decoder{
+		codecCtx: codecCtx,
+		srcFrame: srcFrame,
+	}, nil
+}
+
+// close closes the decoder.
+func (d *h265Decoder) close() {
+	if d.dstFrame != nil {
+		C.av_frame_free(&d.dstFrame)
+	}
+
+	if d.swsCtx != nil {
+		C.sws_freeContext(d.swsCtx)
+	}
+
+	C.av_frame_free(&d.srcFrame)
+	C.avcodec_close(d.codecCtx)
+}
+
+func (d *h265Decoder) decode(nalu []byte) (image.Image, error) {
+	nalu = append([]uint8{0x00, 0x00, 0x00, 0x01}, []uint8(nalu)...)
+
+	// send NALU to decoder
+	var avPacket C.AVPacket
+	avPacket.data = (*C.uint8_t)(C.CBytes(nalu))
+	defer C.free(unsafe.Pointer(avPacket.data))
+	avPacket.size = C.int(len(nalu))
+	res := C.avcodec_send_packet(d.codecCtx, &avPacket)
+	if res < 0 {
+		return nil, nil
+	}
+
+	// receive frame if available
+	res = C.avcodec_receive_frame(d.codecCtx, d.srcFrame)
+	if res < 0 {
+		return nil, nil
+	}
+
+	// if frame size has changed, allocate needed objects
+	if d.dstFrame == nil || d.dstFrame.width != d.srcFrame.width || d.dstFrame.height != d.srcFrame.height {
+		if d.dstFrame != nil {
+			C.av_frame_free(&d.dstFrame)
+		}
+
+		if d.swsCtx != nil {
+			C.sws_freeContext(d.swsCtx)
+		}
+
+		d.dstFrame = C.av_frame_alloc()
+		d.dstFrame.format = C.AV_PIX_FMT_RGBA
+		d.dstFrame.width = d.srcFrame.width
+		d.dstFrame.height = d.srcFrame.height
+		d.dstFrame.color_range = C.AVCOL_RANGE_JPEG
+		res = C.av_frame_get_buffer(d.dstFrame, 1)
+		if res < 0 {
+			return nil, fmt.Errorf("av_frame_get_buffer() failed")
+		}
+
+		d.swsCtx = C.sws_getContext(d.srcFrame.width, d.srcFrame.height, C.AV_PIX_FMT_YUV420P,
+			d.dstFrame.width, d.dstFrame.height, (int32)(d.dstFrame.format), C.SWS_BILINEAR, nil, nil, nil)
+		if d.swsCtx == nil {
+			return nil, fmt.Errorf("sws_getContext() failed")
+		}
+
+		dstFrameSize := C.av_image_get_buffer_size((int32)(d.dstFrame.format), d.dstFrame.width, d.dstFrame.height, 1)
+		d.dstFramePtr = (*[1 << 30]uint8)(unsafe.Pointer(d.dstFrame.data[0]))[:dstFrameSize:dstFrameSize]
+	}
+
+	// convert color space from YUV420 to RGBA
+	res = C.sws_scale(d.swsCtx, frameData(d.srcFrame), frameLineSize(d.srcFrame),
+		0, d.srcFrame.height, frameData(d.dstFrame), frameLineSize(d.dstFrame))
+	if res < 0 {
+		return nil, fmt.Errorf("sws_scale() failed")
+	}
+
+	// embed frame into an image.Image
+	return &image.RGBA{
+		Pix:    d.dstFramePtr,
+		Stride: 4 * (int)(d.dstFrame.width),
+		Rect: image.Rectangle{
+			Max: image.Point{(int)(d.dstFrame.width), (int)(d.dstFrame.height)},
+		},
+	}, nil
+}