1 files changed, 24 insertions, 19 deletions

diff --git a/libavcodec/adpcmenc.c b/libavcodec/adpcmenc.c
index 7027e373dc..c193f5c7ef 100644
--- a/libavcodec/adpcmenc.c
+++ b/libavcodec/adpcmenc.c
@@ -1,20 +1,20 @@
 /*
  * Copyright (c) 2001-2003 The ffmpeg Project
  *
- * This file is part of Libav.
+ * This file is part of FFmpeg.
  *
- * Libav is free software; you can redistribute it and/or
+ * FFmpeg is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Lesser General Public
  * License as published by the Free Software Foundation; either
  * version 2.1 of the License, or (at your option) any later version.
  *
- * Libav is distributed in the hope that it will be useful,
+ * FFmpeg is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  * Lesser General Public License for more details.
  *
  * You should have received a copy of the GNU Lesser General Public
- * License along with Libav; if not, write to the Free Software
+ * License along with FFmpeg; if not, write to the Free Software
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  */
 
@@ -87,6 +87,7 @@ static av_cold int adpcm_encode_init(AVCodecContext *avctx)
         avctx->frame_size = (BLKSIZE - 4 * avctx->channels) * 8 / (4 * avctx->channels) + 1; /* each 16 bits sample gives one nibble */
                                                              /* and we have 4 bytes per channel overhead */
         avctx->block_align = BLKSIZE;
+        avctx->bits_per_coded_sample = 4;
         /* seems frame_size isn't taken into account... have to buffer the samples :-( */
         break;
     case CODEC_ID_ADPCM_IMA_QT:
@@ -97,6 +98,7 @@ static av_cold int adpcm_encode_init(AVCodecContext *avctx)
         avctx->frame_size = (BLKSIZE - 7 * avctx->channels) * 2 / avctx->channels + 2; /* each 16 bits sample gives one nibble */
                                                              /* and we have 7 bytes per channel overhead */
         avctx->block_align = BLKSIZE;
+        avctx->bits_per_coded_sample = 4;
         avctx->extradata_size = 32;
         extradata = avctx->extradata = av_malloc(avctx->extradata_size);
         if (!extradata)
@@ -163,24 +165,27 @@ static inline unsigned char adpcm_ima_compress_sample(ADPCMChannelStatus *c, sho
 static inline unsigned char adpcm_ima_qt_compress_sample(ADPCMChannelStatus *c, short sample)
 {
     int delta = sample - c->prev_sample;
-    int mask, step = ff_adpcm_step_table[c->step_index];
-    int diff = step >> 3;
-    int nibble = 0;
+    int diff, step = ff_adpcm_step_table[c->step_index];
+    int nibble = 8*(delta < 0);
 
-    if (delta < 0) {
-        nibble = 8;
-        delta = -delta;
-    }
+    delta= abs(delta);
+    diff = delta + (step >> 3);
 
-    for (mask = 4; mask;) {
-        if (delta >= step) {
-            nibble |= mask;
-            delta -= step;
-            diff += step;
-        }
-        step >>= 1;
-        mask >>= 1;
+    if (delta >= step) {
+        nibble |= 4;
+        delta -= step;
+    }
+    step >>= 1;
+    if (delta >= step) {
+        nibble |= 2;
+        delta -= step;
+    }
+    step >>= 1;
+    if (delta >= step) {
+        nibble |= 1;
+        delta -= step;
     }
+    diff -= delta;
 
     if (nibble & 8)
         c->prev_sample -= diff;