From: Steinar H. Gunderson <sgunderson@bigfoot.com>
Date: Fri, 5 Aug 2022 20:07:08 +0000 (+0200)
Subject: Use VBR for AV1.
X-Git-Tag: 2.2.0~2
X-Git-Url: https://git.sesse.net/?p=nageru;a=commitdiff_plain;h=02a1350ca615535cc4d5e5f72e191ff34905b25f

Use VBR for AV1.

CBR isn't really ready yet; it requires low-delay mode, which limits
SVT-AV1 to three cores and also is pretty bad for quality in general.
(Also, its CBR isn't really CBR yet; see SVT-AV1 bug 1959.)
---

diff --git a/nageru/av1_encoder.cpp b/nageru/av1_encoder.cpp
index da18c6d..371eb0d 100644
--- a/nageru/av1_encoder.cpp
+++ b/nageru/av1_encoder.cpp
@@ -138,6 +138,8 @@ void AV1Encoder::init_av1()
 		exit(EXIT_FAILURE);
 	}
 
+	// NOTE: We don't set CBR, as it requires low-delay mode, which is
+	// generally problematic wrt. quality and performance.
 	config.enc_mode = global_flags.av1_preset;
 	config.intra_period_length = 63;  // Approx. one second, conforms to the (n % 8) - 1 == 0 rule.
 	config.source_width = global_flags.width;
@@ -145,8 +147,6 @@ void AV1Encoder::init_av1()
 	config.frame_rate_numerator = global_flags.av1_fps_num;
 	config.frame_rate_denominator = global_flags.av1_fps_den;
 	config.encoder_bit_depth = global_flags.bit_depth;
-	config.rate_control_mode = 2;  // CBR.
-	config.pred_structure = 1;  // PRED_LOW_DELAY_B (needed for CBR).
 	config.target_bit_rate = global_flags.av1_bitrate * 1000;
 
 	// NOTE: These should be in sync with the ones in quicksync_encoder.cpp (sps_rbsp()).