[FFmpeg-devel] [PATCH v2 034/162] avcodec/rv10: Make VLC tables smaller

Andreas Rheinhardt andreas.rheinhardt at gmail.com
Fri Nov 20 09:19:07 EET 2020


These tables were huge (14 bits) because one needed 14 bits in order to
find out whether a code is valid and in the VLC table or a valid code that
required hacky workarounds due to RealVideo 1.0 using multiple codes
for the same symbol and the code predating the introduction of symbols
tables for VLCs.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at gmail.com>
---
 libavcodec/rv10.c | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/libavcodec/rv10.c b/libavcodec/rv10.c
index 4d4c2b0f2e..0727899337 100644
--- a/libavcodec/rv10.c
+++ b/libavcodec/rv10.c
@@ -47,7 +47,7 @@
 #define RV_GET_MICRO_VER(x) (((x) >> 12) & 0xFF)
 
 #define MAX_VLC_ENTRIES 1023 // Note: Does not include the skip entries.
-#define DC_VLC_BITS 14 // FIXME find a better solution
+#define DC_VLC_BITS        9
 
 typedef struct RVDecContext {
     MpegEncContext m;
@@ -346,14 +346,14 @@ static av_cold void rv10_build_vlc(VLC *vlc, const uint16_t len_count[15],
 
 static av_cold void rv10_init_static(void)
 {
-    static VLC_TYPE table[16896 + 16640][2];
+    static VLC_TYPE table[1472 + 992][2];
 
     rv_dc_lum.table             = table;
-    rv_dc_lum.table_allocated   = 16896;
+    rv_dc_lum.table_allocated   = 1472;
     rv10_build_vlc(&rv_dc_lum, rv_lum_len_count,
                    rv_sym_run_len, FF_ARRAY_ELEMS(rv_sym_run_len));
-    rv_dc_chrom.table           = &table[16896];
-    rv_dc_chrom.table_allocated = 16640;
+    rv_dc_chrom.table           = &table[1472];
+    rv_dc_chrom.table_allocated = 992;
     rv10_build_vlc(&rv_dc_chrom, rv_chrom_len_count,
                    rv_sym_run_len, FF_ARRAY_ELEMS(rv_sym_run_len) - 2);
     ff_h263_decode_init_vlc();
-- 
2.25.1



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