Add --pixel-format option

Allows forcing yuv420p, needed for screensharing with zoom

manpage/wf-recorder.1.scd

@@ -40,6 +40,9 @@ wf-recorder - A simple screen recording program for wlroots-based compositors
 *-m, --muxer*
 	Set the output format to a specific muxer instead of detecting it from the filename.
 
+*-x, --pixel-format*
+	Set the output pixel format. These can be found by running : *ffmpeg -pix_fmts*
+
 *-g, --geometry*            
 	Selects a specific part of the screen.
 

src/frame-writer.cpp

@@ -111,10 +111,24 @@ AVPixelFormat FrameWriter::get_input_format()
         AV_PIX_FMT_BGR0 : AV_PIX_FMT_RGB0;
 }
 
+AVPixelFormat FrameWriter::lookup_pixel_format(std::string pix_fmt)
+{
+    AVPixelFormat fmt = av_get_pix_fmt(pix_fmt.c_str());
+
+    if (fmt != AV_PIX_FMT_NONE)
+      return fmt;
+
+    std::cerr << "Failed to find the pixel format: " << pix_fmt << std::endl;
+    std::exit(-1);
+}
+
 AVPixelFormat FrameWriter::choose_sw_format(AVCodec *codec)
 {
     auto in_fmt = get_input_format();
 
+    if (!params.pix_fmt.empty())
+        return lookup_pixel_format(params.pix_fmt);
+
     /* For codecs such as rawvideo no supported formats are listed */
     if (!codec->pix_fmts)
         return in_fmt;

src/frame-writer.hpp

@@ -51,6 +51,7 @@ struct FrameWriterParams
 
     std::string codec;
     std::string muxer;
+    std::string pix_fmt;
     std::string hw_device; // used only if codec contains vaapi
     std::map<std::string, std::string> codec_options;
 
@@ -78,6 +79,7 @@ class FrameWriter
     AVBufferRef *hw_device_context = NULL;
     AVBufferRef *hw_frame_context = NULL;
 
+    AVPixelFormat lookup_pixel_format(std::string pix_fmt);
     AVPixelFormat choose_sw_format(AVCodec *codec);
     AVPixelFormat get_input_format();
     void init_hw_accel();

src/main.cpp

@@ -523,6 +523,9 @@ With no FILE, start recording the current screen.
   -m, --muxer               Set the output format to a specific muxer instead of detecting it
                             from the filename.
 
+  -x, --pixel-format        Set the output pixel format. These can be found by running:
+                            *ffmpeg -pix_fmts*
+
   -g, --geometry            Selects a specific part of the screen.
 
   -h, --help                Prints this help screen.
@@ -583,6 +586,7 @@ int main(int argc, char *argv[])
         { "output",          required_argument, NULL, 'o' },
         { "file",            required_argument, NULL, 'f' },
         { "muxer",           required_argument, NULL, 'm' },
+        { "pixel-format",    required_argument, NULL, 'x' },
         { "geometry",        required_argument, NULL, 'g' },
         { "codec",           required_argument, NULL, 'c' },
         { "codec-param",     required_argument, NULL, 'p' },
@@ -614,6 +618,10 @@ int main(int argc, char *argv[])
                 params.muxer = optarg;
                 break;
 
+            case 'x':
+                params.pix_fmt = optarg;
+                break;
+
             case 'g':
                 selected_region.set_from_string(optarg);
                 break;