dca_parser: allow the parser to change the sample rate

libavcodec/dca_parser.c

@@ -192,7 +192,6 @@ static int dca_parse(AVCodecParserContext * s,
     /* read the duration and sample rate from the frame header */
     if (!dca_parse_params(buf, buf_size, &duration, &sample_rate)) {
         s->duration = duration;
-        if (!avctx->sample_rate)
         avctx->sample_rate = sample_rate;
     } else
         s->duration = 0;