/
video.go
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/
video.go
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// Copyright (c) 2023, Cogent Core. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// Package video implements a video player widget in Cogent Core.
package video
//go:generate core generate
import (
"bytes"
"encoding/binary"
"image"
"image/draw"
"time"
"cogentcore.org/core/core"
"cogentcore.org/core/system"
"github.com/faiface/beep"
"github.com/faiface/beep/speaker"
"github.com/zergon321/reisen"
)
// Video represents a video playback widget without any controls.
// See [Player] for a version with controls.
//
//types:add
type Video struct {
core.WidgetBase
// Media is the video media.
Media *reisen.Media
// degrees of rotation to apply to the video images
// 90 = left 90, -90 = right 90
Rotation float32
// setting this to true will stop the playing
Stop bool
frameBuffer <-chan *image.RGBA
// target frame number to be played
frameTarg int
// actual frame number displayed
framePlayed int
// frame number to stop playing at, if > 0
frameStop int
}
func (v *Video) OnAdd() {
v.WidgetBase.OnAdd()
v.Scene.AddDirectRender(v)
}
func (v *Video) Destroy() {
v.Scene.DeleteDirectRender(v)
// v.Media.Destroy()
// todo: frameBuffer
v.WidgetBase.Destroy()
}
// DirectRenderImage uploads the current view frame directly into the drawer
func (v *Video) DirectRenderImage(drw system.Drawer, idx int) {
if !v.IsVisible() {
return
}
if v.framePlayed >= v.frameTarg {
return
}
frame, ok := <-v.frameBuffer
if !ok {
v.Stop = true
return
}
v.framePlayed++
drw.SetGoImage(idx, 0, frame, system.NoFlipY)
}
// DirectRenderDraw draws the current image to RenderWin drawer
func (v *Video) DirectRenderDraw(drw system.Drawer, idx int, flipY bool) {
if !v.IsVisible() {
return
}
bb := v.Geom.TotalBBox
drw.Scale(idx, 0, bb, image.Rectangle{}, draw.Src, flipY, v.Rotation)
}
// Open opens the video specified by the given filepath.
func (v *Video) Open(fpath string) error {
// Initialize the audio speaker.
err := speaker.Init(sampleRate, SpeakerSampleRate.N(time.Second/10))
if err != nil {
return err
}
media, err := reisen.NewMedia(fpath)
if err != nil {
return err
}
v.Media = media
return nil
}
// Play starts playing the video at the specified size. Values of 0
// indicate to use the inherent size of the video for that dimension.
func (v *Video) Play(width, height float32) error {
videoFPS, _ := v.Media.Streams()[0].FrameRate()
if videoFPS == 0 || videoFPS > 100 {
videoFPS = 30
}
// seconds per frame for frame ticker
spf := time.Duration(float64(time.Second) / float64(videoFPS))
// fmt.Println(videoFPS, spf)
// Start decoding streams.
var sampleSource <-chan [2]float64
frameBuffer, sampleSource, errChan, err := v.ReadVideoAndAudio()
if err != nil {
return err
}
v.frameBuffer = frameBuffer
start := time.Now()
v.Stop = false
// todo: should set a v.frameStop target, and also get this as an arg
// to set for playing just a snippet. probably need more general timestamp etc stuff there.
v.frameTarg = 0
v.framePlayed = 0
v.NeedsRender()
// Start playing audio samples.
speaker.Play(v.StreamSamples(sampleSource))
_ = errChan
go func() {
for {
// todo: this is causing everything to stop on my sample video that
// has an error a ways into it -- maybe need a buffered chan or something?
// also see commented-out parts where it tries to send the errors
// or something?
// select {
// case err, ok := <-errChan:
// if ok {
// fmt.Println(err)
// // return err
// }
// default:
if v.Stop {
return
}
d := time.Now().Sub(start)
td := time.Duration(v.frameTarg) * spf
shouldStop := v.frameStop > 0 && v.frameTarg >= v.frameStop
if d > td && !shouldStop {
v.AsyncLock()
v.frameTarg++
v.NeedsRender()
v.AsyncUnlock()
} else if v.frameTarg > v.framePlayed {
v.AsyncLock()
v.NeedsRender()
v.AsyncUnlock()
} else if shouldStop {
return
} else {
time.Sleep(td - d)
}
}
}()
return nil
}
const (
frameBufferSize = 1024
sampleRate = 44100
channelCount = 2
bitDepth = 8
sampleBufferSize = 32 * channelCount * bitDepth * 1024
SpeakerSampleRate beep.SampleRate = 44100
)
// ReadVideoAndAudio reads video and audio frames from the opened media and
// sends the decoded data to che channels to be played.
func (v *Video) ReadVideoAndAudio() (<-chan *image.RGBA, <-chan [2]float64, chan error, error) {
frameBuffer := make(chan *image.RGBA, frameBufferSize)
sampleBuffer := make(chan [2]float64, sampleBufferSize)
errs := make(chan error)
err := v.Media.OpenDecode()
if err != nil {
return nil, nil, nil, err
}
videoStream := v.Media.VideoStreams()[0]
err = videoStream.Open()
if err != nil {
return nil, nil, nil, err
}
audioStream := v.Media.AudioStreams()[0]
err = audioStream.Open()
if err != nil {
return nil, nil, nil, err
}
go func() {
for {
packet, gotPacket, err := v.Media.ReadPacket()
if err != nil {
go func(err error) {
errs <- err
}(err)
}
if !gotPacket {
break
}
switch packet.Type() {
case reisen.StreamVideo:
s := v.Media.Streams()[packet.StreamIndex()].(*reisen.VideoStream)
videoFrame, gotFrame, err := s.ReadVideoFrame()
_ = err
// note: this is causing a panic send on closed channel
// if err != nil {
// go func(err error) {
// errs <- err
// }(err)
// }
if !gotFrame {
break
}
if videoFrame == nil {
continue
}
frameBuffer <- videoFrame.Image()
case reisen.StreamAudio:
s := v.Media.Streams()[packet.StreamIndex()].(*reisen.AudioStream)
audioFrame, gotFrame, err := s.ReadAudioFrame()
// note: this is causing a panic send on closed channel
// if err != nil {
// go func(err error) {
// errs <- err
// }(err)
// }
if !gotFrame {
break
}
if audioFrame == nil {
continue
}
// Turn the raw byte data into
// audio samples of type [2]float64.
reader := bytes.NewReader(audioFrame.Data())
// See the README.md file for
// detailed scheme of the sample structure.
for reader.Len() > 0 {
sample := [2]float64{0, 0}
var result float64
err = binary.Read(reader, binary.LittleEndian, &result)
if err != nil {
go func(err error) {
errs <- err
}(err)
}
sample[0] = result
err = binary.Read(reader, binary.LittleEndian, &result)
if err != nil {
go func(err error) {
errs <- err
}(err)
}
sample[1] = result
sampleBuffer <- sample
}
}
}
videoStream.Close()
audioStream.Close()
v.Media.CloseDecode()
close(frameBuffer)
close(sampleBuffer)
close(errs)
}()
return frameBuffer, sampleBuffer, errs, nil
}
// StreamSamples creates a new custom streamer for
// playing audio samples provided by the source channel.
//
// See https://github.com/faiface/beep/wiki/Making-own-streamers
// for reference.
func (v *Video) StreamSamples(sampleSource <-chan [2]float64) beep.Streamer {
return beep.StreamerFunc(func(samples [][2]float64) (n int, ok bool) {
numRead := 0
for i := 0; i < len(samples); i++ {
sample, ok := <-sampleSource
if !ok {
numRead = i + 1
break
}
samples[i] = sample
numRead++
}
if numRead < len(samples) {
return numRead, false
}
return numRead, true
})
}