Use true peak, not sample peak (EBU R128 compliance).

[nageru] / mixer.cpp

diff --git a/mixer.cpp b/mixer.cpp
index 59f520aacdc12a0dbc70998c13da3df890a72a8c..55707490baa706fd842dd13a8bb6b46c51c95984 100644 (file)
--- a/mixer.cpp
+++ b/mixer.cpp
@@ -146,6 +146,8 @@ Mixer::Mixer(const QSurfaceFormat &format)
                "    gl_FragColor = texture2D(cbcr_tex, tc0); \n"
                "} \n";
        cbcr_program_num = resource_pool->compile_glsl_program(cbcr_vert_shader, cbcr_frag_shader);
+
+       r128_state = ebur128_init(2, 48000, EBUR128_MODE_TRUE_PEAK | EBUR128_MODE_M | EBUR128_MODE_S | EBUR128_MODE_I | EBUR128_MODE_LRA);
 }
 
 Mixer::~Mixer()
@@ -161,6 +163,8 @@ Mixer::~Mixer()
                }
                cards[card_index].usb->stop_dequeue_thread();
        }
+
+       ebur128_destroy(&r128_state);
 }
 
 namespace {
@@ -352,6 +356,7 @@ void Mixer::thread_func()
                                        }
                                }
                                if (card_index == 0) {
+                                       ebur128_add_frames_float(r128_state, samples_out.data(), samples_out.size() / 2);
                                        h264_encoder->add_audio(pts_int, move(samples_out));
                                }
                        }
@@ -362,6 +367,23 @@ void Mixer::thread_func()
                        }
                }
 
+               if (audio_level_callback != nullptr) {
+                       double loudness_s, loudness_i, peak_level_l, peak_level_r;
+                       double lra;
+                       ebur128_loudness_shortterm(r128_state, &loudness_s);
+                       ebur128_loudness_global(r128_state, &loudness_i);
+                       ebur128_loudness_range(r128_state, &lra);
+                       ebur128_true_peak(r128_state, 0, &peak_level_l);
+                       ebur128_true_peak(r128_state, 1, &peak_level_r);
+
+                       // FIXME: This is wrong. We need proper support from libebur128 for this.
+                       double loudness_range_low = loudness_i - 0.5 * lra;
+                       double loudness_range_high = loudness_i + 0.5 * lra;
+
+                       audio_level_callback(loudness_s, 20.0 * log10(max(peak_level_l, peak_level_r)),
+                                            loudness_i, loudness_range_low, loudness_range_high);
+               }
+
                // If the first card is reporting a corrupted or otherwise dropped frame,
                // just increase the pts (skipping over this frame) and don't try to compute anything new.
                if (card_copy[0].new_frame->len == 0) {