We have renamed following Macros to avoid name confusion:
REFS_PER_FRAME --> INTER_REFS_PER_FRAME
(= ALTREF_FRAME - LAST_FRAME + 1)
MAX_REF_FRAMES --> TOTAL_REFS_PER_FRAME
(= ALTREF_FRAME - INTRA_FRAME + 1)
INTER_REFS_PER_FRAME specifies the maximum number of reference frames
that each Inter frame may use.
TOTAL_REFS_PER_FRAME is equal to INTER_REFS_PER_FRAME + 1, which
counts the INTRA_FRAME.
Further, at the encoder side, since REF_FRAMES specifies the maximum
number of the reference frames that the encoder may store, REF_FRAMES
is usually larger than INTER_REFS_PER_FRAME. For example, in the
ext-refs experiment, REF_FRAMES == 8, which allows the encoder to
store maximum 8 reference frames in the buffer, but
INTER_REFS_PER_FRAME equals to 6, which allows each Inter frame may
use up to 6 frames out of the 8 buffered frames as its references.
Hence, in order to explore the possibility to store more reference
frames in future patches, we modified a couple of array sizes to
accomodate the case that the number of buffered reference frames is
not always equal to the number of the references that are being used
by each Inter frame.
Change-Id: I19e42ef608946cc76ebfd3e965a05f4b9b93a0b3
This patch removed the experiment of BIDIR_PRED and merged the feature
into the experiment of EXT_REFS:
(1) Each frame now has up to 6 reference frames, namely
LAST_FRAME, LAST2_FRAME, LAST3_FRAME, GOLDEN_FRAME, (forward) and
BWDREF_FRAME, ALTREF_FRAME (backward);
LAST4_FRAME has been removed;
(2) First pass still keeps the 8 updates:
KF_UPDATE, LF_UPDATE, GF_UPDATE, ARF_UPDATE, OVERLAY_UPDATE, and
BRF_UPDATE, LAST_BIPRED_UPDATE, BI_PRED_UPDATE;
(3) show_existing_frame==1 is supported in the experiment of EXT_REFS;
(4) New encoding modes are added for both single-ref and compound cases,
through the use of the 2 extra forward references (LAST2 & LAST3)
and the 1 extra backward reference (BWDREF).
RD performance wise, using Overall PSNR: Avg/BDRate
Bipred only Prev EXT_REFS Current EXT_REFS with bipred
lowres: -3.474/-3.324 -1.748/-1.586 -4.613/-4.387
derflr: -2.097/-1.353 -1.439/-1.215 -3.120/-2.252
midres: -2.129/-1.901 -1.345/-1.185 -2.898/-2.636
If in vp10/encoder/firstpass.h, change BFG_INTERVAL from 2 to 3, i.e. to
use 2 bi-predictive frames than 1, a further improvement may be
obtained:
Current EXT_REFS with bipred
1 bi-predictive frame 2 bi-predictive frames
lowres: -4.613/-4.387 -4.675/-4.465
derflr: -3.120/-2.252 -3.333/-2.516
midres: -2.898/-2.636 -3.406/-3.095
Change-Id: Ib06fe9ea0a5cfd7418a1d79b978ee9d80bf191cb
Major parts have been implemented as follows:
(1) Added BRF_UPDATE, LASTNRF_UPDATE, and NRF_UPDATE in firstpass.c;
(2) Added the handling for the scenario of
"cpi->common.show_existing_frame == 1" at the encoder;
(3) Added a new reference frame of BWDREF_FRAME;
(4) Have bwd-ref work with upsampled references.
Note that when the experiment of "ext_refs" turned on, this experiment
will be turned off automatically currently.
RD performance in Overall PSNR has been improved, compared against the
VP10 baseline:
lowres: Avg -3.312; BDRate -3.154
derflr: Avg -1.927; BDRate -1.176
midres: Avg -2.149; BDRate -2.001
hdres : Avg -0.567; BDRate -0.588
Change-Id: I4c06ff51cc20194bffbd4d2346e57ba3dcf6b62c
