[FFmpeg-devel] [PATCH 1/3] h264_ps: change decode_scaling_matrices so that it takes

[Benoit Fouet]

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From c2606da98ecd04762305734f4f45ca8eaf266459 Mon Sep 17 00:00:00 2001
From: Benoit Fouet <benoit.fouet at free.fr>
Date: Mon, 27 Jun 2016 12:00:39 +0200
Subject: [PATCH 1/3] h264_ps: change decode_scaling_matrices so that it takes
 const {s,p}ps

In order to be able to make SPS const in H264ParamSets,
modify decode_scaling_matrices so that it returns if the scaling
matrix are present in the SPS, instead of altering the input SPS
structure.
---
 libavcodec/h264_ps.c | 11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/libavcodec/h264_ps.c b/libavcodec/h264_ps.c
index 943d953..5d4ddea 100644
--- a/libavcodec/h264_ps.c
+++ b/libavcodec/h264_ps.c
@@ -265,8 +265,8 @@ static void decode_scaling_list(GetBitContext *gb, uint8_t *factors, int size,
         }
 }
 
-static void decode_scaling_matrices(GetBitContext *gb, SPS *sps,
-                                    PPS *pps, int is_sps,
+static int decode_scaling_matrices(GetBitContext *gb, const SPS *sps,
+                                    const PPS *pps, int is_sps,
                                     uint8_t(*scaling_matrix4)[16],
                                     uint8_t(*scaling_matrix8)[64])
 {
@@ -277,8 +277,9 @@ static void decode_scaling_matrices(GetBitContext *gb, SPS *sps,
         fallback_sps ? sps->scaling_matrix8[0] : default_scaling8[0],
         fallback_sps ? sps->scaling_matrix8[3] : default_scaling8[1]
     };
+    int ret = 0;
     if (get_bits1(gb)) {
-        sps->scaling_matrix_present |= is_sps;
+        ret = is_sps;
         decode_scaling_list(gb, scaling_matrix4[0], 16, default_scaling4[0], fallback[0]);        // Intra, Y
         decode_scaling_list(gb, scaling_matrix4[1], 16, default_scaling4[0], scaling_matrix4[0]); // Intra, Cr
         decode_scaling_list(gb, scaling_matrix4[2], 16, default_scaling4[0], scaling_matrix4[1]); // Intra, Cb
@@ -296,6 +297,8 @@ static void decode_scaling_matrices(GetBitContext *gb, SPS *sps,
             }
         }
     }
+
+    return ret;
 }
 
 void ff_h264_ps_uninit(H264ParamSets *ps)
@@ -401,7 +404,7 @@ int ff_h264_decode_seq_parameter_set(GetBitContext *gb, AVCodecContext *avctx,
             goto fail;
         }
         sps->transform_bypass = get_bits1(gb);
-        decode_scaling_matrices(gb, sps, NULL, 1,
+        sps->scaling_matrix_present |= decode_scaling_matrices(gb, sps, NULL, 1,
                                 sps->scaling_matrix4, sps->scaling_matrix8);
     } else {
         sps->chroma_format_idc = 1;
-- 
2.9.0.37.g6d523a3