[FFmpeg-devel] [PATCH] avcodec/mjpegdec: Remove unnecessary reload (PR #20664)

[mkver via ffmpeg-devel <ffmpeg-devel@ffmpeg.org>]

PR #20664 opened by mkver
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20664
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20664.patch

(In a lot of instances, the reloads inside GET_VLC are unnecessary. I will look into removing them soon.)


>From 67edb1a5c31384de7bf3c160da8132fa933e92e9 Mon Sep 17 00:00:00 2001
From: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
Date: Wed, 8 Oct 2025 03:12:19 +0200
Subject: [PATCH] avcodec/mjpegdec: Remove unnecessary reload

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
---
 libavcodec/mjpegdec.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/libavcodec/mjpegdec.c b/libavcodec/mjpegdec.c
index 69bc003490..86dd50ce0c 100644
--- a/libavcodec/mjpegdec.c
+++ b/libavcodec/mjpegdec.c
@@ -853,10 +853,10 @@ static int decode_block(MJpegDecodeContext *s, int16_t *block, int component,
 
         i += ((unsigned)code) >> 4;
             code &= 0xf;
+        // GET_VLC updates the cache if parsing doesn't finish in the first stage.
+        // So we always have at least MIN_CACHE_BITS - 9 > 15 bits left here
+        // and don't need to refill the cache.
         if (code) {
-            if (code > MIN_CACHE_BITS - 16)
-                UPDATE_CACHE(re, &s->gb);
-
             {
                 int cache = GET_CACHE(re, &s->gb);
                 int sign  = (~cache) >> 31;
-- 
2.49.1

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