wavpack: use context reset in appropriate places

This fixes improper flushing in the cases when the same frame is decoded in
several iterations (for being too large to fit into output buffer) and flush is
called mid-decoding and it also resets context in case of decoding errors.
Signed-off-by: Anton Khirnov <anton@khirnov.net>

libavcodec/wavpack.c

@@ -470,6 +470,7 @@ static float wv_get_value_float(WavpackFrameContext *s, uint32_t *crc, int S)
 static void wv_reset_saved_context(WavpackFrameContext *s)
 {
     s->pos = 0;
+    s->samples_left = 0;
     s->sc.crc = s->extra_sc.crc = 0xFFFFFFFF;
 }
 
@@ -582,6 +583,7 @@ static inline int wv_unpack_stereo(WavpackFrameContext *s, GetBitContext *gb, vo
 
     s->samples_left -= count;
     if(!s->samples_left){
+        wv_reset_saved_context(s);
         if(crc != s->CRC){
             av_log(s->avctx, AV_LOG_ERROR, "CRC error\n");
             return -1;
@@ -590,7 +592,6 @@ static inline int wv_unpack_stereo(WavpackFrameContext *s, GetBitContext *gb, vo
             av_log(s->avctx, AV_LOG_ERROR, "Extra bits CRC error\n");
             return -1;
         }
-        wv_reset_saved_context(s);
     }else{
         s->pos = pos;
         s->sc.crc = crc;
@@ -660,6 +661,7 @@ static inline int wv_unpack_mono(WavpackFrameContext *s, GetBitContext *gb, void
 
     s->samples_left -= count;
     if(!s->samples_left){
+        wv_reset_saved_context(s);
         if(crc != s->CRC){
             av_log(s->avctx, AV_LOG_ERROR, "CRC error\n");
             return -1;
@@ -668,7 +670,6 @@ static inline int wv_unpack_mono(WavpackFrameContext *s, GetBitContext *gb, void
             av_log(s->avctx, AV_LOG_ERROR, "Extra bits CRC error\n");
             return -1;
         }
-        wv_reset_saved_context(s);
     }else{
         s->pos = pos;
         s->sc.crc = crc;
@@ -1195,7 +1196,7 @@ static void wavpack_decode_flush(AVCodecContext *avctx)
     int i;
 
     for (i = 0; i < s->fdec_num; i++)
-        s->fdec[i]->samples_left = 0;
+        wv_reset_saved_context(s->fdec[i]);
 }
 
 AVCodec ff_wavpack_decoder = {