Don't allow very short GF groups even when the GF is predicted from an ARF.
This is basically a slightly modified version of the previous patch,
and it has a moderately positive effect (SSIM/PSNR both +0.08% avg
on derf-set). Most clips show no change, except waterfall/coastguard,
each ~ +0.8% SSIM/PSNR. You can see similar effects in other clips
by shortening their length to terminate at a very short last group
of frames.
Change-Id: I7a70de99ca1f9fe6a8b6ca7a6e30e8a4b64383e4
diff --git a/vp8/encoder/firstpass.c b/vp8/encoder/firstpass.c
index 7cf5041..7c07c9b 100644
--- a/vp8/encoder/firstpass.c
+++ b/vp8/encoder/firstpass.c
@@ -1553,6 +1553,24 @@
cpi->gfu_boost = (int)(boost_score * 100.0) >> 4;
+ // Dont allow conventional gf too near the next kf
+ if ((cpi->twopass.frames_to_key - i) < MIN_GF_INTERVAL)
+ {
+ while (i < cpi->twopass.frames_to_key)
+ {
+ i++;
+
+ if (EOF == input_stats(cpi, this_frame))
+ break;
+
+ if (i < cpi->twopass.frames_to_key)
+ {
+ mod_frame_err = calculate_modified_err(cpi, this_frame);
+ gf_group_err += mod_frame_err;
+ }
+ }
+ }
+
// Should we use the alternate refernce frame
if (allow_alt_ref &&
(i >= MIN_GF_INTERVAL) &&
@@ -1675,25 +1693,6 @@
cpi->baseline_gf_interval = i;
}
- // Conventional GF
- if (!cpi->source_alt_ref_pending)
- {
- // Dont allow conventional gf too near the next kf
- if ((cpi->twopass.frames_to_key - cpi->baseline_gf_interval) < MIN_GF_INTERVAL)
- {
- while (cpi->baseline_gf_interval < cpi->twopass.frames_to_key)
- {
- if (EOF == input_stats(cpi, this_frame))
- break;
-
- cpi->baseline_gf_interval++;
-
- if (cpi->baseline_gf_interval < cpi->twopass.frames_to_key)
- gf_group_err += calculate_modified_err(cpi, this_frame);
- }
- }
- }
-
// Now decide how many bits should be allocated to the GF group as a proportion of those remaining in the kf group.
// The final key frame group in the clip is treated as a special case where cpi->twopass.kf_group_bits is tied to cpi->twopass.bits_left.
// This is also important for short clips where there may only be one key frame.
