[vlc-commits] [Git][videolan/vlc][master] 7 commits: mpeg4video: make vlc_log2() unsigned

[Steve Lhomme (@robUx4)]

Steve Lhomme pushed to branch master at VideoLAN / VLC


Commits:
84ba3883 by Steve Lhomme at 2026-08-04T05:55:21+00:00
mpeg4video: make vlc_log2() unsigned

We start from 0 and potential add 16+8+4+3.

The result + 1 can never be smaller than 1.

- - - - -
774a5ce9 by Steve Lhomme at 2026-08-04T05:55:21+00:00
mpeg4video: restrict the size of time increments

It is read from 1 to 32 bits.

- - - - -
8e6fc030 by Steve Lhomme at 2026-08-04T05:55:21+00:00
mpeg4video: make i_modulo_time_base uint64_t

It's always increment with positive values, up to 64 bits.

- - - - -
1c98cce8 by Steve Lhomme at 2026-08-04T05:55:21+00:00
mpeg4video: remove write-only i_fps_den

- - - - -
3f8e4cd9 by Steve Lhomme at 2026-08-04T05:55:21+00:00
mpeg4video: make i_fps_num unsigned

It's read from 16 bits as unsigned and can never be 0 when it's read.

- - - - -
c457861c by Steve Lhomme at 2026-08-04T05:55:21+00:00
mpeg4video: make i_time_ref/i_last_time_ref unsigned

It's always the result of i_modulo_time_base, i_fps_num and i_last_timeincr
which are all unsigned.

- - - - -
1642302f by Steve Lhomme at 2026-08-04T05:55:21+00:00
mpeg4video: restrict the size of i_fps_num

i_fps_num is read from 16 bits.

- - - - -


1 changed file:

- modules/packetizer/mpeg4video.c


Changes:

=====================================
modules/packetizer/mpeg4video.c
=====================================
@@ -71,15 +71,14 @@ typedef struct
     vlc_tick_t i_interpolated_pts;
     vlc_tick_t i_interpolated_dts;
     vlc_tick_t i_last_ref_pts;
-    int64_t i_last_time_ref;
-    int64_t i_time_ref;
+    uint64_t i_last_time_ref;
+    uint64_t i_time_ref;
     int64_t i_last_time;
-    int64_t i_last_timeincr;
+    uint32_t i_last_timeincr;
 
     unsigned int i_flags;
 
-    int         i_fps_num;
-    int         i_fps_den;
+    uint16_t    i_fps_num;
 
     bool  b_frame;
 
@@ -99,7 +98,7 @@ static block_t *ParseMPEGBlock( decoder_t *, block_t * );
 static int ParseVOL( decoder_t *, es_format_t *, uint8_t *, int );
 static int ParseVO( decoder_t *, block_t * );
 static int ParseVOP( decoder_t *, block_t * );
-static int vlc_log2( unsigned int );
+static unsigned vlc_log2( unsigned int );
 
 #define VIDEO_OBJECT_MASK                       0x01f
 #define VIDEO_OBJECT_LAYER_MASK                 0x00f
@@ -438,11 +437,9 @@ static int ParseVOL( decoder_t *p_dec, es_format_t *fmt,
 
     if( bs_read1( &s ) )
     {
-        int i_time_increment_bits = vlc_log2( p_sys->i_fps_num - 1 ) + 1;
+        unsigned i_time_increment_bits = vlc_log2( p_sys->i_fps_num - 1 ) + 1;
 
-        if( i_time_increment_bits < 1 ) i_time_increment_bits = 1;
-
-        p_sys->i_fps_den = bs_read( &s, i_time_increment_bits );
+        bs_skip( &s, i_time_increment_bits ); /* i_fps_den */
     }
     if( i_shape == 0 )
     {
@@ -502,8 +499,9 @@ static int ParseVO( decoder_t *p_dec, block_t *p_vo )
 static int ParseVOP( decoder_t *p_dec, block_t *p_vop )
 {
     decoder_sys_t *p_sys = p_dec->p_sys;
-    int64_t i_time_increment, i_time_ref;
-    int i_modulo_time_base = 0, i_time_increment_bits;
+    uint64_t i_time_ref;
+    uint32_t i_time_increment;
+    uint64_t i_modulo_time_base = 0;
     bs_t s;
 
     if( p_sys->i_fps_num == 0 )
@@ -532,8 +530,7 @@ static int ParseVOP( decoder_t *p_dec, block_t *p_vop )
     if( !bs_read1( &s ) ) return VLC_EGENERIC; /* Marker */
 
     /* VOP time increment */
-    i_time_increment_bits = vlc_log2(p_sys->i_fps_num - 1) + 1;
-    if( i_time_increment_bits < 1 ) i_time_increment_bits = 1;
+    unsigned i_time_increment_bits = vlc_log2(p_sys->i_fps_num - 1) + 1;
     i_time_increment = bs_read( &s, i_time_increment_bits );
 
     /* Interpolate PTS/DTS */
@@ -614,10 +611,10 @@ static int ParseVOP( decoder_t *p_dec, block_t *p_vop )
 }
 
 /* look at libavutil av_log2 ;) */
-static int vlc_log2( unsigned int v )
+static unsigned vlc_log2( unsigned int v )
 {
-    int n = 0;
-    static const int vlc_log2_table[16] =
+    unsigned n = 0;
+    static const unsigned vlc_log2_table[16] =
     {
         0,0,1,1,2,2,2,2, 3,3,3,3,3,3,3,3
     };



View it on GitLab: https://code.videolan.org/videolan/vlc/-/compare/2601ab775855f20bb6ce5a097b7805742ca1139f...1642302f9092b52e072ab615233d5d652b141636

-- 
View it on GitLab: https://code.videolan.org/videolan/vlc/-/compare/2601ab775855f20bb6ce5a097b7805742ca1139f...1642302f9092b52e072ab615233d5d652b141636
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