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avcodec/msmpeg4dec: Reuse identical RL VLCs

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Some of the RLTables used by msmpeg4dec actually coincide with other
RLTables: ff_rl_table[5] coincides with ff_h263_rl_inter (and
ff_rl_table[2] with ff_mpeg4_rl_intra). Given that ff_h263_rl_inter is
always initialized before msmpeg4dec's RLTables are initialized, one can
just reuse the VLC tables by copying the pointers; after all, there are
no ownership issues for static data. This saves 70912B from the .bss
segment, translating into actual memory savings when this decoder is
actually used.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@gmail.com>
This commit is contained in:
Andreas Rheinhardt 2020-12-09 01:41:31 +01:00
parent a3831e81ff
commit d90d0a715f
1 changed files with 4 additions and 1 deletions
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libavcodec/msmpeg4dec.c
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@ -322,7 +322,10 @@ av_cold int ff_msmpeg4_decode_init(AVCodecContext *avctx)
INIT_FIRST_VLC_RL(ff_rl_table[2], 554); INIT_FIRST_VLC_RL(ff_rl_table[2], 554);
INIT_VLC_RL(ff_rl_table[3], 940); INIT_VLC_RL(ff_rl_table[3], 940);
INIT_VLC_RL(ff_rl_table[4], 962); INIT_VLC_RL(ff_rl_table[4], 962);
INIT_VLC_RL(ff_rl_table[5], 554); /* ff_rl_table[5] coincides with ff_h263_rl_inter which has just been
* initialized in ff_h263_decode_init() above. So just copy the VLCs. */
av_assert1(ff_h263_rl_inter.rl_vlc[0]);
memcpy(ff_rl_table[5].rl_vlc, ff_h263_rl_inter.rl_vlc, sizeof(ff_rl_table[5].rl_vlc));
mv = &ff_mv_tables[0]; mv = &ff_mv_tables[0];
INIT_VLC_STATIC(&mv->vlc, MV_VLC_BITS, mv->n + 1, INIT_VLC_STATIC(&mv->vlc, MV_VLC_BITS, mv->n + 1,