Option for setting muxer

README.md

@@ -36,6 +36,11 @@ to select and limit the recording to a part of the screen.
 
 To specify a codec, use the `-c <codec>` option. To modify codec parameters, use `-p <option_name>=<option_value>`
 
+To set a specific output format use the `--muxer` option. For example, to output to a video4linux2 loopback you might use:
+```
+wf-recorder --muxer=v4l2 --codec=rawvideo --file=/dev/video2
+```
+
 To use gpu encoding, use a VAAPI codec (for ex. `h264_vaapi`) and specify a GPU device to use with the `-d` option:
 ```
 wf-recorder -f test-vaapi.mkv -c h264_vaapi -d /dev/dri/renderD128

manpage/wf-recorder.1.scd

@@ -37,6 +37,9 @@ wf-recorder - A simple screen recording program for wlroots-based compositors
 
 	You can check the muxers that your FFmpeg installation supports by running  : *ffmpeg -muxers*
 
+*-m, --muxer*
+	Set the output format to a specific muxer instead of detecting it from the filename.
+
 *-g, --geometry*            
 	Selects a specific part of the screen.
 

src/frame-writer.cpp

@@ -305,11 +305,15 @@ void FrameWriter::init_sws(AVPixelFormat format)
     }
 }
 
-static const char* determine_output_format(const std::string& output_name)
+static const char* determine_output_format(const FrameWriterParams& params)
 {
-    if (output_name.find("rtmp") == 0)
+    if (!params.muxer.empty())
+        return params.muxer.c_str();
+
+    if (params.file.find("rtmp") == 0)
         return "flv";
-    if (output_name.find("udp") == 0)
+
+    if (params.file.find("udp") == 0)
         return "mpegts";
 
     return NULL;
@@ -324,7 +328,7 @@ FrameWriter::FrameWriter(const FrameWriterParams& _params) :
     // Preparing the data concerning the format and codec,
     // in order to write properly the header, frame data and end of file.
     this->outputFmt = av_guess_format(NULL, params.file.c_str(), NULL);
-    auto streamFormat = determine_output_format(params.file);
+    auto streamFormat = determine_output_format(params);
     auto context_ret = avformat_alloc_output_context2(&this->fmtCtx, NULL,
         streamFormat, params.file.c_str());
     if (context_ret < 0)

src/frame-writer.hpp

@@ -46,6 +46,7 @@ struct FrameWriterParams
     InputFormat format;
 
     std::string codec;
+    std::string muxer;
     std::string hw_device; // used only if codec contains vaapi
     std::map<std::string, std::string> codec_options;
 

src/main.cpp

@@ -520,6 +520,9 @@ With no FILE, start recording the current screen.
                             You can check the muxers that your FFmpeg installation supports by
                             running  : ffmpeg -muxers
 
+  -m, --muxer               Set the output format to a specific muxer instead of detecting it
+                            from the filename.
+
   -g, --geometry            Selects a specific part of the screen.
 
   -h, --help                Prints this help screen.
@@ -579,6 +582,7 @@ int main(int argc, char *argv[])
     struct option opts[] = {
         { "output",          required_argument, NULL, 'o' },
         { "file",            required_argument, NULL, 'f' },
+        { "muxer",           required_argument, NULL, 'm' },
         { "geometry",        required_argument, NULL, 'g' },
         { "codec",           required_argument, NULL, 'c' },
         { "codec-param",     required_argument, NULL, 'p' },
@@ -606,6 +610,10 @@ int main(int argc, char *argv[])
                 cmdline_output = optarg;
                 break;
 
+            case 'm':
+                params.muxer = optarg;
+                break;
+
             case 'g':
                 selected_region.set_from_string(optarg);
                 break;