feat(transcode): add a generic transcoding package for encoding/decoding/caching

server/transcode/transcoder_ffmpeg.go

@@ -0,0 +1,39 @@
+package transcode
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os/exec"
+)
+
+type FFmpegTranscoder struct{}
+
+var _ Transcoder = (*FFmpegTranscoder)(nil)
+
+func NewFFmpegTranscoder() *FFmpegTranscoder {
+	return &FFmpegTranscoder{}
+}
+
+var ErrFFmpegExit = fmt.Errorf("ffmpeg exited with non 0 status code")
+
+func (*FFmpegTranscoder) Transcode(ctx context.Context, profile Profile, in string) (io.ReadCloser, error) {
+	name, args, err := parseProfile(profile, in)
+	if err != nil {
+		return nil, fmt.Errorf("split command: %w", err)
+	}
+
+	preader, pwriter := io.Pipe()
+
+	cmd := exec.CommandContext(ctx, name, args...)
+	cmd.Stdout = pwriter
+	if err := cmd.Start(); err != nil {
+		return nil, fmt.Errorf("starting cmd: %w", err)
+	}
+
+	go func() {
+		_ = pwriter.CloseWithError(cmd.Wait())
+	}()
+
+	return preader, nil
+}