forked from deepch/vdk
/
video.go
167 lines (144 loc) · 4.33 KB
/
video.go
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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);
}
int wrap_avcodec_decode_video2_empty(AVCodecContext *ctx, AVFrame *frame, void *data, int size, int *got) {
struct AVPacket pkt = {.data = NULL, .size = 0};
return avcodec_decode_video2(ctx, frame, got, &pkt);
}
*/
import "C"
import (
"fmt"
"image"
"reflect"
"runtime"
"unsafe"
"github.com/FloatKasemtan/vdk/av"
"github.com/FloatKasemtan/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 (self *VideoDecoder) DecodeSingle(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
}
//https://stackoverflow.com/questions/25431413/decode-compressed-frame-to-memory-using-libav-avcodec-decode-video2
if cgotimg == C.int(0) {
cerr = C.wrap_avcodec_decode_video2_empty(ff.codecCtx, frame, unsafe.Pointer(&pkt[0]), C.int(0), &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
}