avcodec/msmpeg4dec: Don't process unnecessarily many coefficients

This code has been added in f5957f3fe2
when support for WMV1 has been added. It was needed for decoding
inter macroblocks, as WMV1 uses a different scantable and
the ScanTable and ScanTable.raster_end was not yet introduced
(the H263 unquantize function instead used a hardcoded version
of ff_zigzag_direct's raster_end). In other words,
there is no reason to continue to do so for WMV1 inter blocks.
(Apart from that: WMV1 inter blocks don't use
dct_unquantize_h263_inter any more, as unquantizing happens
when parsing the block via specialized RL VLC tables.)

It is also not needed for WMV1/2 intra blocks (for non-ac_pred
it uses the correct ScanTable used by the h263 unquantize
intra function; for ac_pred, the number is overridden)
as well as for WMV2 inter-blocks (raster_end is not really
used in this case; the ordinary ScanTable is used in case
abt_type is zero, otherwise there are two different ScanTables
and block_last_index is overridden in wmv2dec.c).

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>

libavcodec/msmpeg4dec.c

@@ -806,7 +806,6 @@ int ff_msmpeg4_decode_block(MpegEncContext * s, int16_t * block,
             i = 63; /* XXX: not optimal */
         }
     }
-    if (s->msmpeg4_version >= MSMP4_WMV1 && i > 0) i=63; //FIXME/XXX optimize
     s->block_last_index[n] = i;
 
     return 0;