improved lambda/qp guessing for motion estimation RD in first pass

this only affects encoding with bframes and rate control

Originally committed as revision 4765 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/mpegvideo.c

@@ -5300,7 +5300,15 @@ static void encode_picture(MpegEncContext *s, int picture_number)
 
     if(s->flags & CODEC_FLAG_PASS2)
         estimate_qp(s, 1);
+    else if(!(s->flags & CODEC_FLAG_QSCALE)){
+        RateControlContext *rcc= &s->rc_context;
 
+        if(s->pict_type==B_TYPE)
+            s->lambda= rcc->last_qscale_for[s->pict_type];
+        else
+            s->lambda= rcc->last_qscale_for[rcc->last_non_b_pict_type];
+        update_qscale(s);
+    }
 
     s->mb_intra=0; //for the rate distortion & bit compare functions
     for(i=1; i<s->avctx->thread_count; i++){

tests/ffmpeg.regression.ref

@@ -59,18 +59,18 @@ stddev:  7.99 PSNR:30.06 bytes:7602176
 7932708 ./data/a-huffyuv.avi
 799d3db687f6cdd7a837ec156efc171f *./data/out.yuv
 stddev:  0.00 PSNR:99.99 bytes:7602176
-24f8d8a1c15c078f1f1e443b85688444 *./data/a-mpeg4-rc.avi
-820964 ./data/a-mpeg4-rc.avi
-8458b4ddaca643a3ec1264c1ee2f4986 *./data/out.yuv
+fc4c71c330fd3f95e05c398c6a7584de *./data/a-mpeg4-rc.avi
+824306 ./data/a-mpeg4-rc.avi
+fb0a9af6dd83b2f1a3ba752b848038f7 *./data/out.yuv
 stddev: 10.41 PSNR:27.77 bytes:7602176
 81078d7852dfd6041ff17b5dc8ed0ffc *./data/a-mpeg4-adv.avi
 600240 ./data/a-mpeg4-adv.avi
 0b7935cee2070f3b838478cea6dc4b3c *./data/out.yuv
 stddev: 10.25 PSNR:27.90 bytes:7602176
-c5478162c76db62162b082594c4e7ee1 *./data/a-mpeg4-thread.avi
-756550 ./data/a-mpeg4-thread.avi
-7e4e2cf2659aa158f5ffed2be45a9c3d *./data/out.yuv
-stddev: 12.31 PSNR:26.31 bytes:7602176
+5da70c628af00fc6d2dba685d24341b6 *./data/a-mpeg4-thread.avi
+764920 ./data/a-mpeg4-thread.avi
+6e3cc8569fd1f39a3657045a8249dbc6 *./data/out.yuv
+stddev: 12.32 PSNR:26.30 bytes:7602176
 50867a2530035615152f1e068c989bfc *./data/a-mpeg4-Q.avi
 899514 ./data/a-mpeg4-Q.avi
 cdb77818e108eab89c9ac4bcaf350e19 *./data/out.yuv

tests/rotozoom.regression.ref

@@ -59,18 +59,18 @@ stddev:  5.34 PSNR:33.56 bytes:7602176
 6454196 ./data/a-huffyuv.avi
 dde5895817ad9d219f79a52d0bdfb001 *./data/out.yuv
 stddev:  0.00 PSNR:99.99 bytes:7602176
-540bdc49a339db675d12cffc9fce2454 *./data/a-mpeg4-rc.avi
-228094 ./data/a-mpeg4-rc.avi
-764d5da4f1c8eda9bd554179ed1ea283 *./data/out.yuv
+95e95dfe42fce9cdbe72688e821022ca *./data/a-mpeg4-rc.avi
+227834 ./data/a-mpeg4-rc.avi
+2e02fa0261c21268d568ddde74f9431e *./data/out.yuv
 stddev:  4.26 PSNR:35.51 bytes:7602176
 6844785bcca74b4b9dc77ce6d21a3871 *./data/a-mpeg4-adv.avi
 172538 ./data/a-mpeg4-adv.avi
 49fecc1105d25ff1c2fc9c0d4cb821b0 *./data/out.yuv
 stddev:  4.84 PSNR:34.41 bytes:7602176
-d5f2da1edcf1979d71bec183e461b5aa *./data/a-mpeg4-thread.avi
-253098 ./data/a-mpeg4-thread.avi
-da1a5a3301ad2bdf5806a51ffa74d4fb *./data/out.yuv
-stddev:  4.06 PSNR:35.93 bytes:7602176
+9f7f5a7da720ba720aa35d72ed062959 *./data/a-mpeg4-thread.avi
+253448 ./data/a-mpeg4-thread.avi
+672eff5de3b19df7b82ed3e6bed8642d *./data/out.yuv
+stddev:  4.05 PSNR:35.96 bytes:7602176
 ddcb9476113fac71ee609018984353ce *./data/a-mpeg4-Q.avi
 165016 ./data/a-mpeg4-Q.avi
 94d8bd3897ac20bb3bef9cf384f9abd0 *./data/out.yuv