From 1c19e2c82d38244887e279d62e1d542e8932a532 Mon Sep 17 00:00:00 2001
From: Hendrik Leppkes <h.leppkes@gmail.com>
Date: Mon, 15 May 2023 12:49:21 +0200
Subject: [PATCH] avcodec/nvdec_mpeg2: fix order of quant matrix coefficients

The matrix coefficients are stored permutated for the IDCT,
rather then in plain raster order, and need to be un-permutated
for the hardware.
---
 libavcodec/nvdec_mpeg12.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/libavcodec/nvdec_mpeg12.c b/libavcodec/nvdec_mpeg12.c
index 300e1d3d88..5408ca4c76 100644
--- a/libavcodec/nvdec_mpeg12.c
+++ b/libavcodec/nvdec_mpeg12.c
@@ -76,8 +76,9 @@ static int nvdec_mpeg12_start_frame(AVCodecContext *avctx, const uint8_t *buffer
     };
 
     for (i = 0; i < 64; ++i) {
-        ppc->QuantMatrixIntra[i] = s->intra_matrix[i];
-        ppc->QuantMatrixInter[i] = s->inter_matrix[i];
+        int n = s->idsp.idct_permutation[i];
+        ppc->QuantMatrixIntra[i] = s->intra_matrix[n];
+        ppc->QuantMatrixInter[i] = s->inter_matrix[n];
     }
 
     return 0;