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 FindDecoder(i interface{}) (*Codec, error) {
var avc *C.AVCodec
switch t := i.(type) {
case string:
cname := C.CString(i.(string))
defer C.free(unsafe.Pointer(cname))
avc = C.avcodec_find_decoder_by_name(cname)
break
case int:
avc = C.avcodec_find_decoder(uint32(i.(int)))
break
default:
return nil, errors.New(fmt.Sprintf("Unable to find codec, unexpected arguments type '%v'", t))
}
if avc == nil {
return nil, errors.New(fmt.Sprintf("Unable to find codec by value '%v'", i))
}
return &Codec{avCodec: avc}, nil
}
func (stream *Stream) init() error {
// need to allocate this first so that it can be closed on error
stream.Frames = make(chan *Frame)
if stream.avstream == nil {
close(stream.Frames)
return errors.New("nil avstream")
}
if stream.cdcctx != nil {
stream.freeCodecContext()
}
stream.cdcctx = stream.avstream.codec
if decoder := C.avcodec_find_decoder(stream.cdcctx.codec_id); decoder == nil || C.avcodec_open2(stream.cdcctx, decoder, nil) < 0 {
stream.cdcctx = nil
close(stream.Frames)
return errors.New("Cannot find decoder for " + C.GoString(C.avcodec_get_name(stream.cdcctx.codec_id)))
}
stream.packets = make(chan *C.AVPacket)
stream.frame = &Frame{}
switch stream.avstream.codec.codec_type {
case C.AVMEDIA_TYPE_AUDIO:
stream.decodeF = avcodec_decode_audio
case C.AVMEDIA_TYPE_VIDEO:
stream.decodeF = avcodec_decode_video
default:
stream.freeCodecContext()
close(stream.Frames)
return errors.New("unsupported codec")
}
return nil
}
func (codecContext *CodecContext) Codec() *Codec {
if codecContext.CodecIsOpen() == false {
codec := C.avcodec_find_decoder(codecContext.codec_id)
if codec == nil {
panic("Codec not found")
}
C.avcodec_open2((*C.struct_AVCodecContext)(codecContext), codec, nil)
}
return (*Codec)(codecContext.codec)
}
func NewDecoder(filename string) (*Decoder, error) {
self := new(Decoder)
// format context
var formatContext *C.AVFormatContext
if C.avformat_open_input(&formatContext, C.CString(filename), nil, nil) != C.int(0) {
return nil, errors.New(fmt.Sprintf("can't open %d", filename))
}
if C.avformat_find_stream_info(formatContext, nil) < 0 {
return nil, errors.New("find stream info error")
}
C.av_dump_format(formatContext, 0, C.CString(filename), 0)
self.FormatContext = formatContext
// streams
var streams []*C.AVStream
header := (*reflect.SliceHeader)(unsafe.Pointer(&streams))
header.Cap = int(formatContext.nb_streams)
header.Len = int(formatContext.nb_streams)
header.Data = uintptr(unsafe.Pointer(formatContext.streams))
self.Streams = streams
for _, stream := range streams {
switch stream.codec.codec_type {
case C.AVMEDIA_TYPE_VIDEO:
self.VideoStreams = append(self.VideoStreams, stream)
case C.AVMEDIA_TYPE_AUDIO:
self.AudioStreams = append(self.AudioStreams, stream)
default: //TODO other stream
}
}
// codecs
for _, stream := range self.Streams {
codec := C.avcodec_find_decoder(stream.codec.codec_id)
if codec == nil {
continue
}
var options *C.AVDictionary
if C.avcodec_open2(stream.codec, codec, &options) < 0 {
return nil, errors.New(fmt.Sprintf("open codec error %v", stream.codec))
}
self.openedCodecs = append(self.openedCodecs, stream.codec)
}
// output channels
self.audioFrames = make(chan *AudioFrame, 1024)
self.timedFrames = make(chan *C.AVFrame)
return self, nil
}
func (c *Coder) Open() {
c.prepare()
c.Codec = C.avcodec_find_decoder(c.Ctx.codec_id)
if c.Codec == nil {
log.Printf("could not find Codec for id %d", c.Ctx.codec_id)
return
}
avcodec_mutex.Lock()
res := C.avcodec_open(c.Ctx, c.Codec)
avcodec_mutex.Unlock()
if res < 0 {
println("error openning codec")
return
}
println("codec openned")
c.Valid = true
}
func avcodec_find_decoder(codec_id int32) _Codec {
return _Codec{codec: C.avcodec_find_decoder(uint32(codec_id))}
}
//Find a registered decoder with a matching codec ID.
func AvcodecFindDecoder(id CodecId) *Codec {
return (*Codec)(C.avcodec_find_decoder((C.enum_AVCodecID)(id)))
}
//Find a registered decoder with a matching codec ID.
//AVCodec *avcodec_find_decoder (enum AVCodecID id)
func Avcodec_find_decoder(id AVCodecID) *AVCodec {
return (*AVCodec)(C.avcodec_find_decoder((C.enum_AVCodecID)(id)))
}
// NewGenerator returns new generator of screenshots for the video file fn.
func NewGenerator(fn string) (_ *Generator, err error) {
avfCtx := C.avformat_alloc_context()
cfn := C.CString(fn)
defer C.free(unsafe.Pointer(cfn))
if C.avformat_open_input(&avfCtx, cfn, nil, nil) != 0 {
return nil, errors.New("can't open input stream")
}
defer func() {
if err != nil {
C.avformat_close_input(&avfCtx)
}
}()
if C.avformat_find_stream_info(avfCtx, nil) < 0 {
return nil, errors.New("can't get stream info")
}
duration := int64(avfCtx.duration) / 1000
bitrate := int(avfCtx.bit_rate) / 1000
numberOfStreams := int(avfCtx.nb_streams)
hdr := reflect.SliceHeader{
Data: uintptr(unsafe.Pointer(avfCtx.streams)),
Len: numberOfStreams,
Cap: numberOfStreams,
}
streams := *(*[]*C.struct_AVStream)(unsafe.Pointer(&hdr))
vStreamIndex := -1
aStreamIndex := -1
for i := 0; i < numberOfStreams; i++ {
if streams[i].codec.codec_type == C.AVMEDIA_TYPE_VIDEO {
vStreamIndex = i
} else if streams[i].codec.codec_type == C.AVMEDIA_TYPE_AUDIO {
aStreamIndex = i
}
}
if vStreamIndex == -1 {
return nil, errors.New("no video stream")
}
avcCtx := streams[vStreamIndex].codec
vCodec := C.avcodec_find_decoder(avcCtx.codec_id)
if vCodec == nil {
return nil, errors.New("can't find decoder")
}
if C.avcodec_open2(avcCtx, vCodec, nil) != 0 {
return nil, errors.New("can't initialize codec context")
}
width := int(avcCtx.width)
height := int(avcCtx.height)
fps := (float64(streams[vStreamIndex].r_frame_rate.num) /
float64(streams[vStreamIndex].r_frame_rate.den))
vCodecName := strings.ToUpper(C.GoString(vCodec.name))
vCodecHuman := C.GoString(vCodec.long_name)
aCodecName := ""
aCodecHuman := ""
if aStreamIndex != -1 {
aacCtx := streams[aStreamIndex].codec
aCodec := C.avcodec_find_decoder(aacCtx.codec_id)
if aCodec != nil {
aCodecName = strings.ToUpper(C.GoString(aCodec.name))
aCodecHuman = C.GoString(aCodec.long_name)
}
}
return &Generator{
Width: width,
Height: height,
Duration: duration,
VideoCodec: vCodecName,
VideoCodecLongName: vCodecHuman,
AudioCodec: aCodecName,
AudioCodecLongName: aCodecHuman,
numberOfStreams: numberOfStreams,
vStreamIndex: vStreamIndex,
aStreamIndex: aStreamIndex,
FPS: fps,
Bitrate: bitrate,
streams: streams,
avfContext: avfCtx,
avcContext: avcCtx,
}, nil
}
func avcodec_find_decoder(codec_id int32) Codec {
var codec Codec
codec.codec = C.avcodec_find_decoder(uint32(codec_id))
return codec
}