From 3c371e70465933c8a96cb9646db4680fb861d313 Mon Sep 17 00:00:00 2001
From: Alexey Khit <alexey.khit@gmail.com>
Date: Thu, 4 May 2023 07:38:49 +0300
Subject: [PATCH] Change FFmpeg output for MJPEG to pipe

---
 internal/ffmpeg/device/devices.go |  4 ++--
 internal/ffmpeg/ffmpeg.go         | 13 +++++++++++--
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/internal/ffmpeg/device/devices.go b/internal/ffmpeg/device/devices.go
index a02cb896..3e657906 100644
--- a/internal/ffmpeg/device/devices.go
+++ b/internal/ffmpeg/device/devices.go
@@ -33,10 +33,10 @@ func GetInput(src string) (string, error) {
 				video = value[0]
 			case "audio":
 				audio = value[0]
-			case "framerate":
-				input += " -framerate " + value[0]
 			case "resolution":
 				input += " -video_size " + value[0]
+			default: // "input_format", "framerate", "video_size"
+				input += " -" + key + " " + value[0]
 			}
 		}
 	}
diff --git a/internal/ffmpeg/ffmpeg.go b/internal/ffmpeg/ffmpeg.go
index c69ad822..51d6c74a 100644
--- a/internal/ffmpeg/ffmpeg.go
+++ b/internal/ffmpeg/ffmpeg.go
@@ -51,14 +51,16 @@ var defaults = map[string]string{
 	"rtsp/udp": "-fflags nobuffer -flags low_delay -timeout 5000000 -user_agent go2rtc/ffmpeg -i {input}",
 
 	// output
-	"output": "-user_agent ffmpeg/go2rtc -rtsp_transport tcp -f rtsp {output}",
+	"output":       "-user_agent ffmpeg/go2rtc -rtsp_transport tcp -f rtsp {output}",
+	"output/mjpeg": "-f mjpeg -",
 
 	// `-preset superfast` - we can't use ultrafast because it doesn't support `-profile main -level 4.1`
 	// `-tune zerolatency` - for minimal latency
 	// `-profile high -level 4.1` - most used streaming profile
 	"h264":  "-c:v libx264 -g 50 -profile:v high -level:v 4.1 -preset:v superfast -tune:v zerolatency -pix_fmt:v yuvj420p",
 	"h265":  "-c:v libx265 -g 50 -profile:v high -level:v 5.1 -preset:v superfast -tune:v zerolatency",
-	"mjpeg": "-c:v mjpeg -force_duplicated_matrix:v 1 -huffman:v 0 -pix_fmt:v yuvj420p",
+	"mjpeg": "-c:v mjpeg",
+	//"mjpeg": "-c:v mjpeg -force_duplicated_matrix:v 1 -huffman:v 0 -pix_fmt:v yuvj420p",
 
 	// https://ffmpeg.org/ffmpeg-codecs.html#libopus-1
 	"opus":       "-c:a libopus -ar:a 48000 -ac:a 2 -application:a voip -compression_level:a 0",
@@ -268,6 +270,13 @@ func parseArgs(s string) *ffmpeg.Args {
 		args.AddCodec("-c copy")
 	}
 
+	// transcoding to only mjpeg
+	if (args.Video == 1 && args.Audio == 0 && query.Get("video") == "mjpeg") ||
+		// no transcoding from mjpeg input
+		(args.Video == 0 && args.Audio == 0 && strings.Contains(args.Input, " mjpeg ")) {
+		args.Output = defaults["output/mjpeg"]
+	}
+
 	return args
 }