Files
mediadevices/pkg/codec/vpx/vpx_decoder.go
2025-09-17 16:50:52 -07:00

148 lines
3.5 KiB
Go

package vpx
/*
#cgo pkg-config: vpx
#include <stdlib.h>
#include <stdint.h>
#include <vpx/vpx_decoder.h>
#include <vpx/vpx_codec.h>
#include <vpx/vpx_image.h>
#include <vpx/vp8dx.h>
vpx_codec_iface_t *ifaceVP8Decoder() {
return vpx_codec_vp8_dx();
}
vpx_codec_iface_t *ifaceVP9Decoder() {
return vpx_codec_vp9_dx();
}
// Allocates a new decoder context
vpx_codec_ctx_t* newDecoderCtx() {
return (vpx_codec_ctx_t*)malloc(sizeof(vpx_codec_ctx_t));
}
// Initializes the decoder
vpx_codec_err_t decoderInit(vpx_codec_ctx_t* ctx, vpx_codec_iface_t* iface) {
return vpx_codec_dec_init_ver(ctx, iface, NULL, 0, VPX_DECODER_ABI_VERSION);
}
// Decodes an encoded frame
vpx_codec_err_t decodeFrame(vpx_codec_ctx_t* ctx, const uint8_t* data, unsigned int data_sz) {
return vpx_codec_decode(ctx, data, data_sz, NULL, 0);
}
// Creates an iterator
vpx_codec_iter_t* newIter() {
return (vpx_codec_iter_t*)malloc(sizeof(vpx_codec_iter_t));
}
// Returns the next decoded frame
vpx_image_t* getFrame(vpx_codec_ctx_t* ctx, vpx_codec_iter_t* iter) {
return vpx_codec_get_frame(ctx, iter);
}
// Frees a decoder context
void freeDecoderCtx(vpx_codec_ctx_t* ctx) {
vpx_codec_destroy(ctx);
free(ctx);
}
*/
import "C"
import (
"fmt"
"image"
"io"
"sync"
"time"
"unsafe"
"github.com/pion/mediadevices/pkg/codec"
"github.com/pion/mediadevices/pkg/prop"
)
type decoder struct {
codec *C.vpx_codec_ctx_t
raw *C.vpx_image_t
cfg *C.vpx_codec_dec_cfg_t
frameIndex int
tStart time.Time
tLastFrame time.Time
reader io.Reader
buf []byte
mu sync.Mutex
closed bool
}
func BuildVideoDecoder(r io.Reader, property prop.Media) (codec.VideoDecoder, error) {
return NewDecoder(r, property)
}
func NewDecoder(r io.Reader, p prop.Media) (codec.VideoDecoder, error) {
cfg := &C.vpx_codec_dec_cfg_t{}
cfg.threads = 1
cfg.w = C.uint(p.Width)
cfg.h = C.uint(p.Height)
codec := C.newDecoderCtx()
if C.decoderInit(codec, C.ifaceVP8Decoder()) != C.VPX_CODEC_OK {
return nil, fmt.Errorf("vpx_codec_dec_init failed")
}
return &decoder{
codec: codec,
cfg: cfg,
reader: r,
buf: make([]byte, 1024*1024),
}, nil
}
func (d *decoder) Read() (image.Image, func(), error) {
n, err := d.reader.Read(d.buf)
if err != nil {
return nil, nil, err
}
if n > 0 {
status := C.decodeFrame(d.codec, (*C.uint8_t)(&d.buf[0]), C.uint(n))
if status != C.VPX_CODEC_OK {
return nil, nil, fmt.Errorf("Decode failed: %v", status)
}
}
var iter C.vpx_codec_iter_t = nil // initialize to NULL to start iteration
input := C.getFrame(d.codec, &iter)
if input == nil {
return nil, nil, io.EOF
}
w := int(input.d_w)
h := int(input.d_h)
yStride := int(input.stride[0])
uStride := int(input.stride[1])
vStride := int(input.stride[2])
ySrc := unsafe.Slice((*byte)(unsafe.Pointer(input.planes[0])), yStride*h)
uSrc := unsafe.Slice((*byte)(unsafe.Pointer(input.planes[1])), uStride*h/2)
vSrc := unsafe.Slice((*byte)(unsafe.Pointer(input.planes[2])), vStride*h/2)
dst := image.NewYCbCr(image.Rect(0, 0, w, h), image.YCbCrSubsampleRatio420)
// copy luma
for r := 0; r < h; r++ {
copy(dst.Y[r*dst.YStride:r*dst.YStride+w], ySrc[r*yStride:r*yStride+w])
}
// copy chroma
for r := 0; r < h/2; r++ {
copy(dst.Cb[r*dst.CStride:r*dst.CStride+w/2], uSrc[r*uStride:r*uStride+w/2])
copy(dst.Cr[r*dst.CStride:r*dst.CStride+w/2], vSrc[r*vStride:r*vStride+w/2])
}
return dst, func() {}, nil
}
func (d *decoder) Close() error {
C.freeDecoderCtx(d.codec)
d.closed = true
return nil
}