AC-3 encoded volume is too high. Revert revision 7160:

bring AC3 encoder output up to input volume level
patch by Bill O'Shaughnessy % bill P oshaughnessy A gmail.com %
+ reg tests update gruntwork by me
Original thread:
date: Nov 21, 2006 11:36PM
subject: [Ffmpeg-devel] Simpler Patch to bring AC3 encoder output up to input level

git-svn-id: file:///var/local/repositories/ffmpeg/trunk@8444 9553f0bf-9b14-0410-a0b8-cfaf0461ba5b

libavcodec/ac3enc.c

@@ -1161,7 +1161,7 @@ static int AC3_encode_frame(AVCodecContext *avctx,
             v = 14 - log2_tab(input_samples, N);
             if (v < 0)
                 v = 0;
-            exp_samples[i][ch] = v - 10;
+            exp_samples[i][ch] = v - 9;
             lshift_tab(input_samples, N, v);
 
             /* do the MDCT */

tests/ffmpeg.regression.ref

@@ -166,7 +166,7 @@ stddev: 10.98 PSNR:27.30 bytes:7602176
 83f8df5d5f84480566af548bb037fceb *./data/out.wav
 stddev:9330.70 PSNR:16.92 bytes:1054720
 stddev:4396.13 PSNR:23.46 bytes:1052672
-dd68110cb7e5388392f89d5160d3a825 *./data/a-ac3.rm
+aefe11ab5067621a1c674859d6413891 *./data/a-ac3.rm
 98203 ./data/a-ac3.rm
 1eea0440091a8f898c9efca99141456e *./data/a-g726.wav
 24280 ./data/a-g726.wav

tests/libav.regression.ref

@@ -5,7 +5,7 @@ ffmpeg regression test
 786446e80ead936e5faa8f5908f19281 *./data/b-libav.asf
 339775 ./data/b-libav.asf
 ./data/b-libav.asf CRC=0x74113749
-1ad618e9fd318eb3483270cf9b9b3f43 *./data/b-libav.rm
+1ce78eeb6881ffe5b649a9b5105de919 *./data/b-libav.rm
 355405 ./data/b-libav.rm
 bdb7484c68db722f66ba1630cf79844c *./data/b-libav.mpg
 378880 ./data/b-libav.mpg

tests/rotozoom.regression.ref

@@ -166,7 +166,7 @@ stddev:  3.44 PSNR:37.39 bytes:7602176
 83f8df5d5f84480566af548bb037fceb *./data/out.wav
 stddev:9330.70 PSNR:16.92 bytes:1054720
 stddev:4396.13 PSNR:23.46 bytes:1052672
-dd68110cb7e5388392f89d5160d3a825 *./data/a-ac3.rm
+aefe11ab5067621a1c674859d6413891 *./data/a-ac3.rm
 98203 ./data/a-ac3.rm
 1eea0440091a8f898c9efca99141456e *./data/a-g726.wav
 24280 ./data/a-g726.wav