func NewCapture(driver, device string) (*Capture, error) {
id := Capture{index: -1}
id.context = C.avformat_alloc_context()
if id.context == (*C.AVFormatContext)(null) {
return nil, fmt.Errorf("allocate output format context failed")
}
_driver := C.CString(driver)
defer C.free(unsafe.Pointer(_driver))
ifmt := C.av_find_input_format(_driver)
if ifmt == (*C.AVInputFormat)(null) {
return nil, fmt.Errorf("cannot find input driver: %s", driver)
}
dev := C.CString(device)
defer C.free(unsafe.Pointer(dev))
if C.avformat_open_input(&(id.context), dev, ifmt, (**C.AVDictionary)(null)) < 0 {
return nil, fmt.Errorf("cannot open device %s", device)
}
if C.avformat_find_stream_info(id.context, (**C.AVDictionary)(null)) < 0 {
return nil, fmt.Errorf("cannot find stream information")
}
num := int(id.context.nb_streams)
streams := (*[1 << 30]*C.AVStream)(unsafe.Pointer(id.context.streams))
var deCtx *C.AVCodecContext
for i := 0; i < num; i++ {
if streams[i].codec.codec_type == C.AVMEDIA_TYPE_VIDEO {
deCtx = streams[i].codec
id.index = i
break
}
}
if id.index == -1 {
return nil, fmt.Errorf("cannot find video stream")
}
codec := C.avcodec_find_decoder(deCtx.codec_id)
if codec == (*C.AVCodec)(null) {
return nil, fmt.Errorf("cannot find decode codec")
}
id.codec = C.avcodec_alloc_context3(codec)
if C.avcodec_copy_context(id.codec, deCtx) != 0 {
return nil, fmt.Errorf("cannot copy codec context")
}
if C.avcodec_open2(id.codec, codec, (**C.struct_AVDictionary)(null)) < 0 {
return nil, fmt.Errorf("cannot open decode codec")
}
id.sws = C.sws_getContext(id.codec.width,
id.codec.height,
id.codec.pix_fmt,
id.codec.width,
id.codec.height,
C.AV_PIX_FMT_YUV420P, C.SWS_BILINEAR, (*C.struct_SwsFilter)(null), (*C.struct_SwsFilter)(null), (*C.double)(null))
id.frame = C.av_frame_alloc()
return &id, nil
}
func (this *Stream) DumpContexCodec(codec *CodecCtx) {
ret := C.avcodec_copy_context(this.avStream.codec, codec.avCodecCtx)
if ret < 0 {
panic("Failed to copy context from input to output stream codec context\n")
}
}
//Copy the settings of the source Context into the destination Context.
func (ctxt *Context) AvcodecCopyContext(ctxt2 *Context) int {
return int(C.avcodec_copy_context((*C.struct_AVCodecContext)(ctxt), (*C.struct_AVCodecContext)(ctxt2)))
}