Merge pull request #517 from skrashevich/230711-jpg-resize

README.md

@@ -921,6 +921,7 @@ API examples:
 
 - MJPEG stream: `http://192.168.1.123:1984/api/stream.mjpeg?src=camera1`
 - JPEG snapshots: `http://192.168.1.123:1984/api/frame.jpeg?src=camera1`
+- JPEG snapshot resized to 100px: `http://192.168.1.123:1984/api/frame.jpeg?src=camera1&h=100`
 
 ### Module: Log
 

internal/ffmpeg/helpers.go

@@ -2,11 +2,17 @@ package ffmpeg
 
 import (
 	"bytes"
+	"fmt"
 	"os/exec"
 )
 
-func TranscodeToJPEG(b []byte) ([]byte, error) {
-	cmd := exec.Command(defaults["bin"], "-hide_banner", "-i", "-", "-f", "mjpeg", "-")
+func TranscodeToJPEG(b []byte, height ...int) ([]byte, error) {
+	cmdArgs := []string{defaults["bin"], "-hide_banner", "-i", "-", "-f", "mjpeg"}
+	if len(height) > 0 {
+		cmdArgs = append(cmdArgs, "-vf", fmt.Sprintf("scale=-1:%d", height[0]))
+	}
+	cmdArgs = append(cmdArgs, "-")
+	cmd := exec.Command(cmdArgs[0], cmdArgs[1:]...)
 	cmd.Stdin = bytes.NewBuffer(b)
 	return cmd.Output()
 }

internal/mjpeg/init.go

@@ -61,9 +61,22 @@ func handlerKeyframe(w http.ResponseWriter, r *http.Request) {
 	case core.CodecH264, core.CodecH265:
 		ts := time.Now()
 		var err error
-		if data, err = ffmpeg.TranscodeToJPEG(data); err != nil {
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
+		// Resize image if "h" parameter exists
+		if hParam := r.URL.Query().Get("h"); hParam != "" {
+			h, err := strconv.Atoi(hParam)
+			if err != nil {
+				http.Error(w, "Invalid height parameter", http.StatusBadRequest)
+				return
+			}
+			if data, err = ffmpeg.TranscodeToJPEG(data, h); err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
+		} else {
+			if data, err = ffmpeg.TranscodeToJPEG(data); err != nil {
+				http.Error(w, err.Error(), http.StatusInternalServerError)
+				return
+			}
 		}
 		log.Debug().Msgf("[mjpeg] transcoding time=%s", time.Since(ts))
 	}