From 3a3f605a564bf5b05569ce3e52474775e89eb7bb Mon Sep 17 00:00:00 2001
From: Tim Sweet <tsweet64@protonmail.com>
Date: Fri, 11 Mar 2022 18:24:16 -0600
Subject: [PATCH] decoder/opus: Implement bitrate calculation

---
 NEWS                                      | 2 ++
 src/decoder/plugins/OpusDecoderPlugin.cxx | 9 ++++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/NEWS b/NEWS
index d51ab7bce..43dc6795e 100644
--- a/NEWS
+++ b/NEWS
@@ -4,6 +4,8 @@ ver 0.24 (not yet released)
   - filter "prio" (for "playlistfind"/"playlistsearch")
 * archive
   - add option to disable archive plugins in mpd.conf
+* decoder
+  - opus: implement bitrate calculation
 * player
   - add option "mixramp_analyzer" to scan MixRamp tags on-the-fly
 * tags
diff --git a/src/decoder/plugins/OpusDecoderPlugin.cxx b/src/decoder/plugins/OpusDecoderPlugin.cxx
index 18216ed31..c35914236 100644
--- a/src/decoder/plugins/OpusDecoderPlugin.cxx
+++ b/src/decoder/plugins/OpusDecoderPlugin.cxx
@@ -327,6 +327,13 @@ MPDOpusDecoder::HandleAudio(const ogg_packet &packet)
 			return;
 	}
 
+	/* Formula for calculation of bitrate of the current opus packet:
+	   bits_sent_into_decoder = packet.bytes * 8
+	   1/seconds_decoded = opus_sample_rate / nframes
+	   kbits = bits_sent_into_decoder * 1/seconds_decoded / 1000
+	*/
+	uint16_t kbits = (unsigned int)packet.bytes*8 * opus_sample_rate / nframes / 1000;
+
 	/* apply the "skip" value */
 	if (skip >= (unsigned)nframes) {
 		skip -= nframes;
@@ -361,7 +368,7 @@ MPDOpusDecoder::HandleAudio(const ogg_packet &packet)
 	const size_t nbytes = nframes * frame_size;
 	auto cmd = client.SubmitData(input_stream,
 				     data, nbytes,
-				     0);
+				     kbits);
 	if (cmd != DecoderCommand::NONE)
 		throw cmd;