Merge pull request #147 from mheers/feature/timecode

Feature: read timecode from frames

format_go112.go

@@ -1,3 +1,4 @@
+//go:build go1.12
 // +build go1.12
 
 // Format.
@@ -364,6 +365,21 @@ func (ctx *FmtCtx) GetNextPacket() (*Packet, error) {
 	return pkt, nil
 }
 
+func (ctx *FmtCtx) GetNextPacketForStreamIndex(streamIndex int) (*Packet, error) {
+	for {
+		packet, err := ctx.GetNextPacket()
+		if err != nil {
+			return nil, fmt.Errorf("failed to get next packet: %s", err)
+		}
+
+		if packet.StreamIndex() == streamIndex {
+			return packet, nil
+		}
+
+		packet.Free()
+	}
+}
+
 func (ctx *FmtCtx) GetNewPackets() chan *Packet {
 	yield := make(chan *Packet)
 
@@ -547,6 +563,72 @@ func (ctx *FmtCtx) SeekFrameAt(sec int64, streamIndex int) error {
 	return nil
 }
 
+func (ctx *FmtCtx) SeekFrameAtTimeCode(timecode string, streamIndex int) error {
+	ist, err := ctx.GetStream(streamIndex)
+	if err != nil {
+		return err
+	}
+
+	istCodecCtx := ist.CodecCtx()
+	istAvgFrameRate := ist.GetAvgFrameRate()
+
+	sec := int64(0)
+
+	found := false
+	for !found {
+		packet, err := ctx.GetNextPacket()
+		if err != nil {
+			return err
+		}
+		if packet.StreamIndex() != streamIndex {
+			continue
+		}
+
+		found, err = isPacketLaterThanTimeCode(packet, timecode, istCodecCtx, istAvgFrameRate)
+		if err != nil {
+			return err
+		}
+		if !found {
+			sec += 5
+			err = ctx.SeekFrameAt(sec, streamIndex)
+			if err != nil {
+				return err
+			}
+		}
+
+		packet.Free()
+	}
+
+	return nil
+}
+
+func isPacketLaterThanTimeCode(packet *Packet, timecode string, codecCtx *CodecCtx, avgFrameRate AVRational) (bool, error) {
+	frameTimeCode, err := getPacketTimeCode(packet, codecCtx, avgFrameRate)
+	if err != nil {
+		return false, err
+	}
+	if frameTimeCode >= timecode {
+		return true, nil
+	}
+	return false, nil
+}
+
+func getPacketTimeCode(packet *Packet, codecCtx *CodecCtx, avgFrameRate AVRational) (string, error) {
+	frames, err := codecCtx.Decode(packet)
+	if err != nil {
+		return "", err
+	}
+	for _, frame := range frames {
+		timecode, err := frame.GetTimeCode(avgFrameRate)
+		if err != nil {
+			return "", err
+		}
+		frame.Free()
+		return timecode, nil
+	}
+	return "", nil
+}
+
 func (ctx *FmtCtx) SetPb(val *AVIOContext) *FmtCtx {
 	ctx.avCtx.pb = val.avAVIOContext
 	ctx.customPb = true

frame_go112.go

@@ -1,3 +1,4 @@
+//go:build go1.12
 // +build go1.12
 
 package gmf
@@ -5,10 +6,13 @@ package gmf
 /*
 #cgo pkg-config: libavcodec libavutil
 
+#include <stdlib.h>
 #include "libavcodec/avcodec.h"
 #include "libavutil/frame.h"
 #include "libavutil/imgutils.h"
 #include "libavutil/timestamp.h"
+#include "libavutil/timecode.h"
+#include "libavutil/common.h"
 
 void gmf_set_frame_data(AVFrame *frame, int idx, int l_size, uint8_t data) {
     if(!frame) {
@@ -26,6 +30,15 @@ void gmf_free_data(AVFrame *frame) {
 	av_freep(&frame->data[0]);
 }
 
+int gmf_get_timecode(AVFrameSideData *sd, AVRational avgFrameRate, char *out) {
+	uint32_t *tc = (uint32_t*)sd->data;
+	char tcbuf[AV_TIMECODE_STR_SIZE];
+	av_timecode_make_smpte_tc_string2(tcbuf, avgFrameRate, tc[1], 0, 0);
+	int n;
+	n = sprintf(out, "%s", tcbuf);
+	return n;
+}
+
 */
 import "C"
 
@@ -276,3 +289,98 @@ func (f *Frame) GetRawAudioData(plane int) []byte {
 func (f *Frame) Time(timebase AVRational) int {
 	return int(float64(timebase.AVR().Num) / float64(timebase.AVR().Den) * float64(f.Pts()))
 }
+
+var frameSideDataTypes []uint32 = []uint32{
+	C.AV_FRAME_DATA_PANSCAN,
+	C.AV_FRAME_DATA_A53_CC,
+	C.AV_FRAME_DATA_AFD,
+	C.AV_FRAME_DATA_AUDIO_SERVICE_TYPE,
+	C.AV_FRAME_DATA_CONTENT_LIGHT_LEVEL,
+	C.AV_FRAME_DATA_DISPLAYMATRIX,
+	C.AV_FRAME_DATA_DOWNMIX_INFO,
+	C.AV_FRAME_DATA_DYNAMIC_HDR_PLUS,
+	C.AV_FRAME_DATA_FILM_GRAIN_PARAMS,
+	C.AV_FRAME_DATA_GOP_TIMECODE,
+	C.AV_FRAME_DATA_ICC_PROFILE,
+	C.AV_FRAME_DATA_MASTERING_DISPLAY_METADATA,
+	C.AV_FRAME_DATA_MATRIXENCODING,
+	C.AV_FRAME_DATA_MOTION_VECTORS,
+	C.AV_FRAME_DATA_QP_TABLE_DATA,
+	C.AV_FRAME_DATA_QP_TABLE_PROPERTIES,
+	C.AV_FRAME_DATA_REGIONS_OF_INTEREST,
+	C.AV_FRAME_DATA_REPLAYGAIN,
+	C.AV_FRAME_DATA_S12M_TIMECODE,
+	C.AV_FRAME_DATA_SEI_UNREGISTERED,
+	C.AV_FRAME_DATA_SKIP_SAMPLES,
+	C.AV_FRAME_DATA_SPHERICAL,
+	C.AV_FRAME_DATA_STEREO3D,
+	C.AV_FRAME_DATA_VIDEO_ENC_PARAMS,
+}
+
+func (f *Frame) GetSideDataTypes() (map[uint32]string, error) {
+	result := make(map[uint32]string)
+	// get a pointer to the side data of the frame
+	for _, sideDataType := range frameSideDataTypes {
+		sideDataPtr := C.av_frame_get_side_data(f.avFrame, sideDataType)
+		if sideDataPtr != nil {
+			// cast the pointer to the side data to a AVFrameSideData struct
+			sideData := (*C.struct_AVFrameSideData)(unsafe.Pointer(sideDataPtr))
+
+			sideDataType := C.GoString(C.av_frame_side_data_name(sideData._type))
+			result[uint32(sideData._type)] = sideDataType
+		}
+	}
+
+	return result, nil
+}
+
+func (f *Frame) GetUserData() ([]byte, error) {
+	// get a pointer to the side data of the frame
+	sideDataPtr := C.av_frame_get_side_data(f.avFrame, C.AV_FRAME_DATA_SEI_UNREGISTERED)
+
+	if sideDataPtr == nil {
+		return nil, errors.New("no user data found")
+	}
+
+	// cast the pointer to the side data to a AVFrameSideData struct
+	sideData := (*C.struct_AVFrameSideData)(unsafe.Pointer(sideDataPtr))
+
+	// gets the bytes from the pointer
+	data := C.GoBytes(unsafe.Pointer(sideData.data), C.int(sideData.size))
+
+	return data, nil
+}
+
+func (f *Frame) GetTimeCode(avgFrameRate AVRational) (string, error) {
+	// get a pointer to the side data of the frame
+	sideDataPtr := C.av_frame_get_side_data(f.avFrame, C.AV_FRAME_DATA_S12M_TIMECODE)
+
+	if sideDataPtr == nil {
+		return "", errors.New("no timecode data found")
+	}
+
+	// cast the pointer to the side data to a AVFrameSideData struct
+	sideData := (*C.struct_AVFrameSideData)(unsafe.Pointer(sideDataPtr))
+
+	// check if the side data is valid
+	if sideData._type != C.AV_FRAME_DATA_S12M_TIMECODE || sideData.size != 16 {
+		return "", errors.New("invalid timecode side data")
+	}
+
+	// prepare a byte slice to hold the timecode
+	ptr := C.malloc(C.sizeof_char * 1024)
+	defer C.free(unsafe.Pointer(ptr))
+
+	// cast the go avgFrameRate to a C AVRational
+	afr := (C.struct_AVRational)(avgFrameRate)
+
+	// get the timecode by calling the C function and passing the sideData, the AVRational and the pointer to the byte slice to hold the timecode
+	// returns the length of the timecode in bytes
+	tcSize := C.gmf_get_timecode(sideData, afr, (*C.char)(ptr))
+
+	// gets the bytes from the pointer
+	tc := C.GoBytes(ptr, tcSize)
+
+	tcString := string(tc)
+	return tcString, nil
+}