frame.go

package reisen

// #cgo pkg-config: libavutil libavformat libavcodec  libswscale
// #include <libavcodec/avcodec.h>
// #include <libavformat/avformat.h>
// #include <libavutil/avutil.h>
// #include <libavutil/imgutils.h>
// #include <libswscale/swscale.h>
// #include <inttypes.h>
import "C"

import (
	"fmt"
	"time"
)

// Frame is an abstract data frame.
type Frame interface {
	Data() []byte
	PresentationOffset() (time.Duration, error)
}

// baseFrame contains the information
// common for all frames of any type.
type baseFrame struct {
	stream Stream
	pts    int64
}

// PresentationOffset returns the duration offset
// since the start of the media at which the frame
// should be played.
func (frame *baseFrame) PresentationOffset() (time.Duration, error) {
	tbNum, tbDen := frame.stream.TimeBase()
	tb := float64(tbNum) / float64(tbDen)
	tm := float64(frame.pts) * tb

	return time.ParseDuration(fmt.Sprintf("%fs", tm))
}