Add a menu option to change x264 video bitrate while running.

[nageru] / x264_encoder.cpp

diff --git a/x264_encoder.cpp b/x264_encoder.cpp
index 7be454c75c8e0bc33394f4a1ddd610af05b07e40..756d673bfb40b2adc6588992e3b78c2fd3b14d3f 100644 (file)
--- a/x264_encoder.cpp
+++ b/x264_encoder.cpp
@@ -14,6 +14,24 @@ extern "C" {
 
 using namespace std;
 
+namespace {
+
+void update_vbv_settings(x264_param_t *param)
+{
+       if (global_flags.x264_vbv_buffer_size < 0) {
+               param->rc.i_vbv_buffer_size = param->rc.i_bitrate;  // One-second VBV.
+       } else {
+               param->rc.i_vbv_buffer_size = global_flags.x264_vbv_buffer_size;
+       }
+       if (global_flags.x264_vbv_max_bitrate < 0) {
+               param->rc.i_vbv_max_bitrate = param->rc.i_bitrate;  // CBR.
+       } else {
+               param->rc.i_vbv_max_bitrate = global_flags.x264_vbv_max_bitrate;
+       }
+}
+
+}  // namespace
+
 X264Encoder::X264Encoder(AVOutputFormat *oformat)
        : wants_global_headers(oformat->flags & AVFMT_GLOBALHEADER)
 {
@@ -83,16 +101,7 @@ void X264Encoder::init_x264()
 
        param.rc.i_rc_method = X264_RC_ABR;
        param.rc.i_bitrate = global_flags.x264_bitrate;
-       if (global_flags.x264_vbv_buffer_size < 0) {
-               param.rc.i_vbv_buffer_size = param.rc.i_bitrate;  // One-second VBV.
-       } else {
-               param.rc.i_vbv_buffer_size = global_flags.x264_vbv_buffer_size;
-       }
-       if (global_flags.x264_vbv_max_bitrate < 0) {
-               param.rc.i_vbv_max_bitrate = param.rc.i_bitrate;  // CBR.
-       } else {
-               param.rc.i_vbv_max_bitrate = global_flags.x264_vbv_max_bitrate;
-       }
+       update_vbv_settings(&param);
        if (param.rc.i_vbv_max_bitrate > 0) {
                // If the user wants VBV control to cap the max rate, it is
                // also reasonable to assume that they are fine with the stream
@@ -234,6 +243,17 @@ void X264Encoder::encode_frame(X264Encoder::QueuedFrame qf)
                input_pic = &pic;
        }
 
+       // See if we have a new bitrate to change to.
+       unsigned new_rate = new_bitrate_kbit.exchange(0);  // Read and clear.
+       if (new_rate != 0) {
+               x264_param_t param;
+               x264_encoder_parameters(x264, &param);
+               param.rc.i_bitrate = new_rate;
+               update_vbv_settings(&param);
+               x264_encoder_reconfig(x264, &param);
+               printf("changing rate to %u\n", new_rate);
+       }
+
        if (speed_control) {
                speed_control->before_frame(float(free_frames.size()) / X264_QUEUE_LENGTH, X264_QUEUE_LENGTH, 1e6 * qf.duration / TIMEBASE);
        }