89 lines
1.8 KiB
Go
89 lines
1.8 KiB
Go
package codec
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import (
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/*
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#include <libavcodec/avcodec.h>
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#include <libavformat/avformat.h>
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#include <libavutil/avutil.h>
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typedef struct {
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AVCodec *c;
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AVCodecContext *ctx;
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AVFrame *f;
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int got;
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} h264dec_t ;
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static int h264dec_new(h264dec_t *h, uint8_t *data, int len) {
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h->c = avcodec_find_decoder(CODEC_ID_H264);
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h->ctx = avcodec_alloc_context3(h->c);
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h->f = av_frame_alloc();
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h->ctx->extradata = data;
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h->ctx->extradata_size = len;
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h->ctx->debug = 0x3;
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return avcodec_open2(h->ctx, h->c, 0);
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}
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static int h264dec_decode(h264dec_t *h, uint8_t *data, int len) {
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AVPacket pkt;
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av_init_packet(&pkt);
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pkt.data = data;
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pkt.size = len;
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return avcodec_decode_video2(h->ctx, h->f, &h->got, &pkt);
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}
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*/
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"C"
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"errors"
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"image"
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"unsafe"
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)
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type H264Decoder struct {
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m C.h264dec_t
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}
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func NewH264Decoder(header []byte) (m *H264Decoder, err error) {
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m = &H264Decoder{}
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r := C.h264dec_new(
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&m.m,
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(*C.uint8_t)(unsafe.Pointer(&header[0])),
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(C.int)(len(header)),
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)
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if int(r) < 0 {
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err = errors.New("open codec failed")
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}
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return
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}
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func (m *H264Decoder) Decode(nal []byte) (f *image.YCbCr, err error) {
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r := C.h264dec_decode(
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&m.m,
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(*C.uint8_t)(unsafe.Pointer(&nal[0])),
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(C.int)(len(nal)),
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)
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if int(r) < 0 {
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err = errors.New("decode failed")
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return
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}
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if m.m.got == 0 {
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err = errors.New("no picture")
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return
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}
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w := int(m.m.f.width)
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h := int(m.m.f.height)
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ys := int(m.m.f.linesize[0])
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cs := int(m.m.f.linesize[1])
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f = &image.YCbCr{
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Y: fromCPtr(unsafe.Pointer(m.m.f.data[0]), ys*h),
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Cb: fromCPtr(unsafe.Pointer(m.m.f.data[1]), cs*h/2),
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Cr: fromCPtr(unsafe.Pointer(m.m.f.data[2]), cs*h/2),
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YStride: ys,
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CStride: cs,
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SubsampleRatio: image.YCbCrSubsampleRatio420,
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Rect: image.Rect(0, 0, w, h),
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}
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return
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}
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