FrameRate Changes, Implement CFR and estimated buffer framerate

config.h.in

@@ -1,7 +1,6 @@
 #pragma once
 
 #define DEFAULT_CODEC "@default_codec@"
-#define DEFAULT_FRAMERATE @default_framerate@
 #define DEFAULT_AUDIO_CODEC "@default_audio_codec@"
 #define DEFAULT_AUDIO_SAMPLE_RATE @default_audio_sample_rate@
 #define DEFAULT_CONTAINER_FORMAT "@default_container_format@"

manpage/wf-recorder.1

@@ -9,6 +9,7 @@
 .Op Fl abcCdDefFghlmopPrRvxX
 .Op Fl a, -audio Op Ar =DEVICE
 .Op Fl b, -bframes Ar max_b_frames
+.Op Fl B, -buffrate Ar buffrate
 .Op Fl c, -codec Ar output_codec
 .Op Fl r, -framerate Ar framerate
 .Op Fl d, -device Ar encoding_device
@@ -61,6 +62,10 @@ You can find your device by running
 .Pp
 .It Fl b , -bframes Ar max_b_frames
 Sets the maximum number of B-Frames to use.
+.It Fl B , -buffrate Ar buffrate
+Tells the encoder a prediction of what framerate to expect. 
+This preserves VFR and Solves FPS limit issue of some encoders (like svt-av1).
+Should be set to the same framerate as display.
 .Pp
 .It Fl c , -codec Ar output_codec
 Specifies the codec of the video. Supports GIF output as well.
@@ -69,7 +74,8 @@ To modify codec parameters, use
 .Fl p Ar option_name=option_value
 .Pp
 .It Fl r , -framerate Ar framerate
-Changes an approximation of the video framerate. The default is 60.
+Sets hard constant framerate. Will duplicate frames to reach it. 
+This makes the resulting video CFR. Solves FPS limit issue of some encoders.
 .Pp
 .It Fl d , -device Ar encoding_device
 Selects the device to use when encoding the video.

meson.build

@@ -16,7 +16,6 @@ project(
 conf_data = configuration_data()
 
 conf_data.set('default_codec', get_option('default_codec'))
-conf_data.set('default_framerate', get_option('default_framerate'))
 conf_data.set('default_audio_codec', get_option('default_audio_codec'))
 conf_data.set('default_audio_sample_rate', get_option('default_audio_sample_rate'))
 conf_data.set('default_container_format', get_option('default_container_format'))

meson_options.txt

@@ -1,5 +1,4 @@
 option('default_codec', type: 'string', value: 'libvpx', description: 'Codec that will be used by default')
-option('default_framerate', type: 'integer', value: 60, description: 'Video framerate that will be used by default')
 option('default_audio_codec', type: 'string', value: 'libvorbis', description: 'Audio codec that will be used by default')
 option('default_audio_sample_rate', type: 'integer', value: 48000, description: 'Audio sample rate that will be used by default')
 option('default_container_format', type: 'string', value: 'webm', description: 'Container file format that will be used by default')

src/frame-writer.cpp

@@ -177,6 +177,15 @@ void FrameWriter::init_video_filters(const AVCodec *codec)
         }
     }
 
+    if (params.framerate != 0){
+        if (params.video_filter != "null" && params.video_filter.find("fps") == std::string::npos) {
+            params.video_filter += ",fps=" + std::to_string(params.framerate);
+        }
+        else if (params.video_filter == "null"){
+            params.video_filter = "fps=" + std::to_string(params.framerate);
+        } 
+    }
+
     this->videoFilterGraph = avfilter_graph_alloc();
     av_opt_set(videoFilterGraph, "scale_sws_opts", "flags=fast_bilinear:src_range=1:dst_range=1", 0);
 
@@ -195,6 +204,9 @@ void FrameWriter::init_video_filters(const AVCodec *codec)
     buffer_filter_config << "video_size=" << params.width << "x" << params.height;
     buffer_filter_config << ":pix_fmt=" << (int)this->get_input_format();
     buffer_filter_config << ":time_base=" << US_RATIONAL.num << "/" << US_RATIONAL.den;
+    if (params.buffrate != 0) {
+        buffer_filter_config << ":frame_rate=" << params.buffrate;
+    }
     buffer_filter_config << ":pixel_aspect=1/1";
 
     int err = avfilter_graph_create_filter(&this->videoFilterSourceCtx, source,
@@ -330,7 +342,9 @@ void FrameWriter::init_video_stream()
     videoCodecCtx->height     = params.height;
     videoCodecCtx->time_base  = US_RATIONAL;
     videoCodecCtx->color_range = AVCOL_RANGE_JPEG;
+    if (params.framerate) {
     std::cout << "Framerate: " << params.framerate << std::endl;
+    }
 
     if (params.bframes != -1)
         videoCodecCtx->max_b_frames = params.bframes;

src/frame-writer.hpp

@@ -60,8 +60,9 @@ struct FrameWriterParams
     std::string hw_device; // used only if codec contains vaapi
     std::map<std::string, std::string> codec_options;
     std::map<std::string, std::string> audio_codec_options;
-    int framerate;
+    int framerate = 0;
     int sample_rate;
+    int buffrate = 0;
 
     int64_t audio_sync_offset;
 

src/main.cpp

@@ -561,7 +561,7 @@ Use Ctrl+C to stop.)");
                             ffmpeg -encoders
                             To modify codec parameters, use -p <option_name>=<option_value>
 
-  -r, --framerate           Changes an approximation of the video framerate. The default is 60.
+  -r, --framerate           Changes framerate to constant framerate with a given value.
 
   -d, --device              Selects the device to use when encoding the video
                             Some drivers report support for rgb0 data for vaapi input but
@@ -604,6 +604,9 @@ Use Ctrl+C to stop.)");
 
   -b, --bframes             This option is used to set the maximum number of b-frames to be used.
                             If b-frames are not supported by your hardware, set this to 0.
+
+  -B. --buffrate            This option is used to specify the buffers expected framerate. this 
+                            may help when encoders are expecting specifc or limited framerate.
 
   -C, --audio-codec         Specifies the codec of the audio. These can be found by running:
                             ffmpeg -encoders
@@ -699,7 +702,6 @@ int main(int argc, char *argv[])
     FrameWriterParams params = FrameWriterParams(exit_main_loop);
     params.file = "recording." + std::string(DEFAULT_CONTAINER_FORMAT);
     params.codec = DEFAULT_CODEC;
-    params.framerate = DEFAULT_FRAMERATE;
     params.audio_codec = DEFAULT_AUDIO_CODEC;
     params.sample_rate = DEFAULT_AUDIO_SAMPLE_RATE;
     params.enable_ffmpeg_debug_output = false;
@@ -728,13 +730,14 @@ int main(int argc, char *argv[])
         { "audio",             optional_argument, NULL, 'a' },
         { "help",              no_argument,       NULL, 'h' },
         { "bframes",           required_argument, NULL, 'b' },
+        { "buffrate",          required_argument, NULL, 'B' },
         { "version",           no_argument,       NULL, 'v' },
         { "no-damage",         no_argument,       NULL, 'D' },
         { 0,                   0,                 NULL,  0  }
     };
 
     int c, i;
-    while((c = getopt_long(argc, argv, "o:f:m:g:c:p:r:x:C:P:R:X:d:b:la::hvDF:", opts, &i)) != -1)
+    while((c = getopt_long(argc, argv, "o:f:m:g:c:p:r:x:C:P:R:X:d:b:B:la::hvDF:", opts, &i)) != -1)
     {
         switch(c)
         {
@@ -790,6 +793,10 @@ int main(int argc, char *argv[])
                 params.bframes = atoi(optarg);
                 break;
 
+            case 'B':
+                params.buffrate = atoi(optarg);
+                break;
+
             case 'l':
                 params.enable_ffmpeg_debug_output = true;
                 break;