owncast/core/transcoder/thumbnailGenerator.go
2022-06-20 22:10:55 -07:00

140 lines
3.4 KiB
Go

package transcoder
import (
"os"
"os/exec"
"path"
"strconv"
"strings"
"time"
log "github.com/sirupsen/logrus"
"github.com/owncast/owncast/config"
"github.com/owncast/owncast/core/data"
"github.com/owncast/owncast/utils"
)
var _timer *time.Ticker
// StopThumbnailGenerator will stop the periodic generating of a thumbnail from video.
func StopThumbnailGenerator() {
if _timer != nil {
_timer.Stop()
}
}
// StartThumbnailGenerator starts generating thumbnails.
func StartThumbnailGenerator(chunkPath string, variantIndex int) {
// Every 20 seconds create a thumbnail from the most
// recent video segment.
_timer = time.NewTicker(20 * time.Second)
quit := make(chan struct{})
go func() {
for {
select {
case <-_timer.C:
if err := fireThumbnailGenerator(chunkPath, variantIndex); err != nil {
log.Errorln("Unable to generate thumbnail:", err)
}
case <-quit:
log.Debug("thumbnail generator has stopped")
_timer.Stop()
return
}
}
}()
}
func fireThumbnailGenerator(segmentPath string, variantIndex int) error {
// JPG takes less time to encode than PNG
outputFile := path.Join(config.TempDir, "thumbnail.jpg")
previewGifFile := path.Join(config.TempDir, "preview.gif")
framePath := path.Join(segmentPath, strconv.Itoa(variantIndex))
files, err := os.ReadDir(framePath)
if err != nil {
return err
}
var modTime time.Time
var names []string
for _, f := range files {
if path.Ext(f.Name()) != ".ts" {
continue
}
fi, err := f.Info()
if err != nil {
continue
}
if fi.Mode().IsRegular() {
if !fi.ModTime().Before(modTime) {
if fi.ModTime().After(modTime) {
modTime = fi.ModTime()
names = names[:0]
}
names = append(names, fi.Name())
}
}
}
if len(names) == 0 {
return nil
}
mostRecentFile := path.Join(framePath, names[0])
ffmpegPath := utils.ValidatedFfmpegPath(data.GetFfMpegPath())
outputFileTemp := path.Join(config.TempDir, "tempthumbnail.jpg")
thumbnailCmdFlags := []string{
ffmpegPath,
"-y", // Overwrite file
"-threads 1", // Low priority processing
"-t 1", // Pull from frame 1
"-i", mostRecentFile, // Input
"-f image2", // format
"-vframes 1", // Single frame
outputFileTemp,
}
ffmpegCmd := strings.Join(thumbnailCmdFlags, " ")
if _, err := exec.Command("sh", "-c", ffmpegCmd).Output(); err != nil {
return err
}
// rename temp file
if err := utils.Move(outputFileTemp, outputFile); err != nil {
log.Errorln(err)
}
makeAnimatedGifPreview(mostRecentFile, previewGifFile)
return nil
}
func makeAnimatedGifPreview(sourceFile string, outputFile string) {
ffmpegPath := utils.ValidatedFfmpegPath(data.GetFfMpegPath())
outputFileTemp := path.Join(config.TempDir, "temppreview.gif")
// Filter is pulled from https://engineering.giphy.com/how-to-make-gifs-with-ffmpeg/
animatedGifFlags := []string{
ffmpegPath,
"-y", // Overwrite file
"-threads 1", // Low priority processing
"-i", sourceFile, // Input
"-t 1", // Output is one second in length
"-filter_complex", "\"[0:v] fps=8,scale=w=480:h=-1:flags=lanczos,split [a][b];[a] palettegen=stats_mode=full [p];[b][p] paletteuse=new=1\"",
outputFileTemp,
}
ffmpegCmd := strings.Join(animatedGifFlags, " ")
if _, err := exec.Command("sh", "-c", ffmpegCmd).Output(); err != nil {
log.Errorln(err)
// rename temp file
} else if err := utils.Move(outputFileTemp, outputFile); err != nil {
log.Errorln(err)
}
}