atrac: Move doxygen comments to the header

Also update copyright info and file description.
Signed-off-by: Diego Biurrun <diego@biurrun.de>

libavcodec/atrac.c

 /*
- * ATRAC common functions
- * Copyright (c) 2006-2008 Maxim Poliakovski
+ * common functions for the ATRAC family of decoders
+ *
+ * Copyright (c) 2006-2013 Maxim Poliakovski
  * Copyright (c) 2006-2008 Benjamin Larsson
  *
  * This file is part of Libav.
@@ -44,10 +45,6 @@ static const float qmf_48tap_half[24] = {
    -0.043596379,   -0.099384367,   0.13207909,    0.46424159
 };
 
-/**
- * Generate common tables
- */
-
 void ff_atrac_generate_tables(void)
 {
     int i;
@@ -66,19 +63,6 @@ void ff_atrac_generate_tables(void)
         }
 }
 
-
-/**
- * Quadrature mirror synthesis filter.
- *
- * @param inlo      lower part of spectrum
- * @param inhi      higher part of spectrum
- * @param nIn       size of spectrum buffer
- * @param pOut      out buffer
- * @param delayBuf  delayBuf buffer
- * @param temp      temp buffer
- */
-
-
 void ff_atrac_iqmf (float *inlo, float *inhi, unsigned int nIn, float *pOut, float *delayBuf, float *temp)
 {
     int   i, j;

libavcodec/atrac.h

 /*
- * ATRAC common data
- * Copyright (c) 2009 Maxim Poliakovski
+ * common functions for the ATRAC family of decoders
+ *
+ * Copyright (c) 2009-2013 Maxim Poliakovski
  * Copyright (c) 2009 Benjamin Larsson
  *
  * This file is part of Libav.
@@ -30,7 +31,21 @@
 
 extern float ff_atrac_sf_table[64];
 
+/**
+ * Generate common tables.
+ */
 void ff_atrac_generate_tables(void);
+
+/**
+ * Quadrature mirror synthesis filter.
+ *
+ * @param inlo      lower part of spectrum
+ * @param inhi      higher part of spectrum
+ * @param nIn       size of spectrum buffer
+ * @param pOut      out buffer
+ * @param delayBuf  delayBuf buffer
+ * @param temp      temp buffer
+ */
 void ff_atrac_iqmf (float *inlo, float *inhi, unsigned int nIn, float *pOut, float *delayBuf, float *temp);
 
 #endif /* AVCODEC_ATRAC_H */