AV1Enc: Fixing VBR quality issue
CTS test uncovered quality issue in case of rapid content change in VBR
mode. Because of libaom VBR resulted in >20% BR increase on some files,
we are using AOM CBR (for MediaCodec VBR) with the following restrictions:
1. Buffer control variables are set to default (for VBR)
2. MaxQP is set to 52. This will also allow to maintain quality floor
Test: atest DecodeEditEncodeTest
Bug: b/279671663
Change-Id: Ie9f2fbbc09c44104759fdef30d90c5009abbc0fe
diff --git a/media/codec2/components/aom/C2SoftAomEnc.cpp b/media/codec2/components/aom/C2SoftAomEnc.cpp
index 59cad9d..e8b0506 100644
--- a/media/codec2/components/aom/C2SoftAomEnc.cpp
+++ b/media/codec2/components/aom/C2SoftAomEnc.cpp
@@ -542,15 +542,15 @@
mCodecConfiguration->kf_max_dist = 3000;
// Encoder determines optimal key frame placement automatically.
mCodecConfiguration->kf_mode = AOM_KF_AUTO;
- // Initial value of the buffer level in ms.
- mCodecConfiguration->rc_buf_initial_sz = 500;
- // Amount of data that the encoder should try to maintain in ms.
- mCodecConfiguration->rc_buf_optimal_sz = 600;
// The amount of data that may be buffered by the decoding
// application in ms.
mCodecConfiguration->rc_buf_sz = 1000;
if (mBitrateControlMode == AOM_CBR) {
+ // Initial value of the buffer level in ms.
+ mCodecConfiguration->rc_buf_initial_sz = 500;
+ // Amount of data that the encoder should try to maintain in ms.
+ mCodecConfiguration->rc_buf_optimal_sz = 600;
// Maximum amount of bits that can be subtracted from the target
// bitrate - expressed as percentage of the target bitrate.
mCodecConfiguration->rc_undershoot_pct = 100;
@@ -563,7 +563,7 @@
mCodecConfiguration->rc_undershoot_pct = 100;
// Maximum amount of bits that can be added to the target
// bitrate - expressed as percentage of the target bitrate.
- mCodecConfiguration->rc_overshoot_pct = 25;
+ mCodecConfiguration->rc_overshoot_pct = 100;
}
if (mIntf->getSyncFramePeriod() >= 0) {
@@ -576,6 +576,12 @@
}
if (mMaxQuantizer > 0) {
mCodecConfiguration->rc_max_quantizer = mMaxQuantizer;
+ } else {
+ if (mBitrateControlMode == AOM_VBR) {
+ // For VBR we are limiting MaxQP to 52 (down 11 steps) to maintain quality
+ // 52 comes from experiments done on libaom standalone app
+ mCodecConfiguration->rc_max_quantizer = 52;
+ }
}
mCodecContext = new aom_codec_ctx_t;