From: Michael Niedermayer <michael@niedermayer.cc>
To: FFmpeg development discussions and patches <ffmpeg-devel@ffmpeg.org>
Subject: [FFmpeg-devel] [PATCH 9/9] avcodec/vlc: simplify min/maxbits in multi VLC
Date: Sun, 22 Oct 2023 23:51:13 +0200
Message-ID: <20231022215113.3469-9-michael@niedermayer.cc> (raw)
In-Reply-To: <20231022215113.3469-1-michael@niedermayer.cc>
nothing uses maxbits, so its removed
minbits is just the last entry (verified with assert on fate)
This basically reverts 58d9b5caf3d332c6495f9af437158bf45531a05e for the minbits computation
Signed-off-by: Michael Niedermayer <michael@niedermayer.cc>
---
libavcodec/vlc.c | 13 ++++---------
1 file changed, 4 insertions(+), 9 deletions(-)
diff --git a/libavcodec/vlc.c b/libavcodec/vlc.c
index ceabeba5408..de16424c93d 100644
--- a/libavcodec/vlc.c
+++ b/libavcodec/vlc.c
@@ -395,7 +395,7 @@ static int vlc_multi_gen(VLC_MULTI_ELEM *table, const VLC *single,
const int is16bit, const int nb_codes, const int numbits,
VLCcode *buf, void *logctx)
{
- int minbits, maxbits, max;
+ int minbits, max;
unsigned count[VLC_MULTI_MAX_SYMBOLS-1] = { 0, };
VLC_MULTI_ELEM info = { { 0, }, 0, 0, };
int count0 = 0;
@@ -407,14 +407,9 @@ static int vlc_multi_gen(VLC_MULTI_ELEM *table, const VLC *single,
}
}
- minbits = 32;
- maxbits = 0;
-
- for (int n = nb_codes - count0; n < nb_codes; n++) {
- minbits = FFMIN(minbits, buf[n].bits);
- maxbits = FFMAX(maxbits, buf[n].bits);
- }
- av_assert0(maxbits <= numbits);
+ //This is only correct if count0 > 0 and the table is sorted
+ //minbits is not used if count0 == 0 and other parts assume the table is sorted too
+ minbits = buf[nb_codes - 1].bits;
for (max = nb_codes; max > nb_codes - count0; max--) {
// We can only add a code that fits with the shortest other code into the table
--
2.17.1
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next prev parent reply other threads:[~2023-10-22 21:52 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-10-22 21:51 [FFmpeg-devel] [PATCH 1/9] avcodec/vlc: merge lost 16bit end of array check Michael Niedermayer
2023-10-22 21:51 ` [FFmpeg-devel] [PATCH 2/9] avcodec/vlc: dont pass nb_elems into multi vlc code Michael Niedermayer
2023-10-22 21:51 ` [FFmpeg-devel] [PATCH 3/9] avcodec/vlc: Skip subtable entries in multi VLC Michael Niedermayer
2023-10-22 21:51 ` [FFmpeg-devel] [PATCH 4/9] avcodec/vlc: Replace mysterious max computation code in multi vlc Michael Niedermayer
2023-10-22 21:51 ` [FFmpeg-devel] [PATCH 5/9] avcodec/vlc: Pass VLC_MULTI_ELEM directly not by pointer Michael Niedermayer
2023-10-23 6:10 ` Leo Izen
2023-10-23 16:04 ` Michael Niedermayer
2023-10-24 9:54 ` Leo Izen
2023-10-31 22:22 ` Michael Niedermayer
2023-10-22 21:51 ` [FFmpeg-devel] [PATCH 6/9] avcodec/vlc: Remove mysterious jitter loop in multi VLC Michael Niedermayer
2023-10-22 21:51 ` [FFmpeg-devel] [PATCH 7/9] Revert "avcodec/vlc: add correct upper limit for recursive function" Michael Niedermayer
2023-10-22 21:51 ` [FFmpeg-devel] [PATCH 8/9] Revert "avcodec/vlc: fix off by one in limit check for multi" Michael Niedermayer
2023-10-22 21:51 ` Michael Niedermayer [this message]
2023-10-22 23:02 ` [FFmpeg-devel] [PATCH 1/9] avcodec/vlc: merge lost 16bit end of array check Paul B Mahol
2023-10-23 16:05 ` Michael Niedermayer
2023-10-26 22:35 ` Michael Niedermayer
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