increasing precission of the quantization parameter

this is needed as the quantization stepsize for each subband is also in this precission and insignificant changes to the wavelet like scaling its coefficients slightly differently would lead to wildly variing PSNR and bitrate
note, a encoder could also simply choose to leave the least significant bits of the quantization parameters zero which would give the exact previous behaviour except a y very tiny number of bits in  the header

Originally committed as revision 4115 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/snow.c

@@ -31,7 +31,7 @@
 #define MAX_DECOMPOSITIONS 8
 #define MAX_PLANES 4
 #define DWTELEM int
-#define QSHIFT 3
+#define QSHIFT 5
 #define QROOT (1<<QSHIFT)
 #define LOSSLESS_QLOG -128
 #define FRAC_BITS 8

tests/ffmpeg.regression.ref

@@ -119,12 +119,12 @@ a7ef4746f27be309138c188e327d3ebe *./data/a-ffv1.avi
 2653642 ./data/a-ffv1.avi
 799d3db687f6cdd7a837ec156efc171f *./data/out.yuv
 stddev:  0.00 PSNR:99.99 bytes:7602176
-3e7738ae0429e48d3465d4f941eb7448 *./data/a-snow.avi
-1280602 ./data/a-snow.avi
-e4b8c83278efee032a84569c25593937 *./data/out.yuv
-stddev:  2.92 PSNR:38.79 bytes:7602176
-45687368463932f08dbc74c973ad32dd *./data/a-snow53.avi
-3537042 ./data/a-snow53.avi
+15527997420c2ace9ab26e4504f7ca8d *./data/a-snow.avi
+1269510 ./data/a-snow.avi
+20e858677a35136bfa0765fafd3f9385 *./data/out.yuv
+stddev:  2.96 PSNR:38.67 bytes:7602176
+28b6a82fdd8058e2df35778c9a5edbbf *./data/a-snow53.avi
+3537074 ./data/a-snow53.avi
 799d3db687f6cdd7a837ec156efc171f *./data/out.yuv
 stddev:  0.00 PSNR:99.99 bytes:7602176
 b5b6275f58f012de73644bbaa9080097 *./data/a-svq1.mov

tests/rotozoom.regression.ref

@@ -119,12 +119,12 @@ d0831a8339491fd680b650f05262e5d9 *./data/a-ffv1.avi
 3524768 ./data/a-ffv1.avi
 dde5895817ad9d219f79a52d0bdfb001 *./data/out.yuv
 stddev:  0.00 PSNR:99.99 bytes:7602176
-6e0ea3a5128f54f42e5fdb81532d95fe *./data/a-snow.avi
-332700 ./data/a-snow.avi
-1f3439e1b3ff09492f196a024d7119e3 *./data/out.yuv
-stddev:  2.37 PSNR:40.60 bytes:7602176
-92ab639886be86087942dd76cfd91bf3 *./data/a-snow53.avi
-2724572 ./data/a-snow53.avi
+7b3468914d99ff2803c35560a0a4a6f0 *./data/a-snow.avi
+327494 ./data/a-snow.avi
+3c1e7765d9be2af73e992c2f6d769e7b *./data/out.yuv
+stddev:  2.40 PSNR:40.52 bytes:7602176
+8b510a8e4a26d6d469bd80b46922d5e6 *./data/a-snow53.avi
+2724602 ./data/a-snow53.avi
 dde5895817ad9d219f79a52d0bdfb001 *./data/out.yuv
 stddev:  0.00 PSNR:99.99 bytes:7602176
 920c610ec324b772d882b0717e375943 *./data/a-svq1.mov