baresip: add avcodec: constrain bitrate patch

Makefile

@@ -63,7 +63,8 @@ external:
 	cd external/baresip && \
 		patch -p1 < ../../patches/baresip_packet_dup_handler.patch && \
 		patch -p1 < ../../patches/baresip_stream_enable.patch && \
-		patch -p1 < ../../patches/baresip_video_remove_sendq_empty.patch
+		patch -p1 < ../../patches/baresip_video_remove_sendq_empty.patch && \
+		patch -p1 < ../../patches/2365.patch
 
 .PHONY: cloc
 cloc:

patches/2365.patch

@@ -0,0 +1,29 @@
+From 8897f63134635868ae0d4cd21f06a58880bc1f9c Mon Sep 17 00:00:00 2001
+From: Sebastian Reimers <[email protected]>
+Date: Fri, 23 Dec 2022 10:59:04 +0100
+Subject: [PATCH] avcodec: constrain bitrate
+
+With rc_buffer_size and rc_max_rate the encoder can better calculate
+a constant average bitrate and this avoids large bitrate spikes.
+
+See: https://trac.ffmpeg.org/wiki/Limiting%20the%20output%20bitrate
+---
+ modules/avcodec/encode.c | 5 ++++-
+ 1 file changed, 4 insertions(+), 1 deletion(-)
+
+diff --git a/modules/avcodec/encode.c b/modules/avcodec/encode.c
+index 8ce4eb8b5..b45cd0947 100644
+--- a/modules/avcodec/encode.c
++++ b/modules/avcodec/encode.c
+@@ -164,7 +164,10 @@ static int open_encoder(struct videnc_state *st,
+
+ 	av_opt_set_defaults(st->ctx);
+
+-	st->ctx->bit_rate  = prm->bitrate;
++	st->ctx->bit_rate	= prm->bitrate;
++	st->ctx->rc_max_rate	= prm->bitrate;
++	st->ctx->rc_buffer_size = prm->bitrate / 2;
++
+ 	st->ctx->width     = size->w;
+ 	st->ctx->height    = size->h;
+