[FFmpeg-devel] [PATCH] avcodec/intrax8: Fix assert

Andreas Rheinhardt andreas.rheinhardt at outlook.com
Wed Feb 28 11:10:54 EET 2024


Andreas Rheinhardt:
> Commit 900ce6f8c3526f27173057bb955f54f4f4f41246 replaced
> IntraX8Context.ac_vlc by IntraX8Context.ac_vlc_table,
> but forgot to update an av_assert2()*.
> cf7ed01938a4d8b2ccd28f1fadacd79103e54eed then
> replaced this with a check for j_ac_vlc[mode],
> but this makes no sense as j_ac_vlc is of type
> const VLCElem [2][2][8][].
> 
> Worse yet, mode can be up to three and then
> j_ac_vlc[mode] is undefined behaviour. This happened
> during the wmv8-x8intra FATE test.
> 
> *: Since 84f16bb5e68dc47eca4dc96b3391c58471cd7328
> config.h was no longer auto-included in avassert.h
> and this disabled av_assert1() and av_assert2()
> in files where config.h has not been included before
> the inclusion of avassert.h.
> 
> Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt at outlook.com>
> ---
>  libavcodec/intrax8.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/libavcodec/intrax8.c b/libavcodec/intrax8.c
> index b6aacb170a..948391599f 100644
> --- a/libavcodec/intrax8.c
> +++ b/libavcodec/intrax8.c
> @@ -103,7 +103,7 @@ static inline void x8_select_ac_table(IntraX8Context *const w, int mode)
>      table_index       = get_bits(w->gb, 3);
>      // 2 modes use same tables
>      w->j_ac_vlc_table[mode] = j_ac_vlc[w->quant < 13][mode >> 1][table_index];
> -    av_assert2(j_ac_vlc[mode]);
> +    av_assert2(w->j_ac_vlc_table[mode]);
>  }
>  
>  static inline int x8_get_orient_vlc(IntraX8Context *w)

Will apply this patch tomorrow unless there are objections.

- Andreas



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