first commit

cgo/ffmpeg/video.go

@@ -0,0 +1,124 @@
+package ffmpeg
+
+/*
+#include "ffmpeg.h"
+int wrap_avcodec_decode_video2(AVCodecContext *ctx, AVFrame *frame, void *data, int size, int *got) {
+	struct AVPacket pkt = {.data = data, .size = size};
+	return avcodec_decode_video2(ctx, frame, got, &pkt);
+}
+*/
+import "C"
+import (
+	"fmt"
+	"image"
+	"reflect"
+	"runtime"
+	"unsafe"
+
+	"github.com/deepch/vdk/av"
+	"github.com/deepch/vdk/codec/h264parser"
+)
+
+type VideoDecoder struct {
+	ff        *ffctx
+	Extradata []byte
+}
+
+func (self *VideoDecoder) Setup() (err error) {
+	ff := &self.ff.ff
+	if len(self.Extradata) > 0 {
+		ff.codecCtx.extradata = (*C.uint8_t)(unsafe.Pointer(&self.Extradata[0]))
+		ff.codecCtx.extradata_size = C.int(len(self.Extradata))
+	}
+	if C.avcodec_open2(ff.codecCtx, ff.codec, nil) != 0 {
+		err = fmt.Errorf("ffmpeg: decoder: avcodec_open2 failed")
+		return
+	}
+	return
+}
+
+func fromCPtr(buf unsafe.Pointer, size int) (ret []uint8) {
+	hdr := (*reflect.SliceHeader)((unsafe.Pointer(&ret)))
+	hdr.Cap = size
+	hdr.Len = size
+	hdr.Data = uintptr(buf)
+	return
+}
+
+type VideoFrame struct {
+	Image image.YCbCr
+	frame *C.AVFrame
+}
+
+func (self *VideoFrame) Free() {
+	self.Image = image.YCbCr{}
+	C.av_frame_free(&self.frame)
+}
+
+func freeVideoFrame(self *VideoFrame) {
+	self.Free()
+}
+
+func (self *VideoDecoder) Decode(pkt []byte) (img *VideoFrame, err error) {
+	ff := &self.ff.ff
+
+	cgotimg := C.int(0)
+	frame := C.av_frame_alloc()
+	cerr := C.wrap_avcodec_decode_video2(ff.codecCtx, frame, unsafe.Pointer(&pkt[0]), C.int(len(pkt)), &cgotimg)
+	if cerr < C.int(0) {
+		err = fmt.Errorf("ffmpeg: avcodec_decode_video2 failed: %d", cerr)
+		return
+	}
+
+	if cgotimg != C.int(0) {
+		w := int(frame.width)
+		h := int(frame.height)
+		ys := int(frame.linesize[0])
+		cs := int(frame.linesize[1])
+
+		img = &VideoFrame{Image: image.YCbCr{
+			Y:              fromCPtr(unsafe.Pointer(frame.data[0]), ys*h),
+			Cb:             fromCPtr(unsafe.Pointer(frame.data[1]), cs*h/2),
+			Cr:             fromCPtr(unsafe.Pointer(frame.data[2]), cs*h/2),
+			YStride:        ys,
+			CStride:        cs,
+			SubsampleRatio: image.YCbCrSubsampleRatio420,
+			Rect:           image.Rect(0, 0, w, h),
+		}, frame: frame}
+		runtime.SetFinalizer(img, freeVideoFrame)
+	}
+
+	return
+}
+
+func NewVideoDecoder(stream av.CodecData) (dec *VideoDecoder, err error) {
+	_dec := &VideoDecoder{}
+	var id uint32
+
+	switch stream.Type() {
+	case av.H264:
+		h264 := stream.(h264parser.CodecData)
+		_dec.Extradata = h264.AVCDecoderConfRecordBytes()
+		id = C.AV_CODEC_ID_H264
+
+	default:
+		err = fmt.Errorf("ffmpeg: NewVideoDecoder codec=%v unsupported", stream.Type())
+		return
+	}
+
+	c := C.avcodec_find_decoder(id)
+	if c == nil || C.avcodec_get_type(id) != C.AVMEDIA_TYPE_VIDEO {
+		err = fmt.Errorf("ffmpeg: cannot find video decoder codecId=%d", id)
+		return
+	}
+
+	if _dec.ff, err = newFFCtxByCodec(c); err != nil {
+		return
+	}
+	if err = _dec.Setup(); err != nil {
+		return
+	}
+
+	dec = _dec
+	return
+}