[FFmpeg-devel] [PATCH] avcodec/hevc_ps: Remove dead code in vps_id check

[Andriy Gelman]

From: Andriy Gelman <andriy.gelman at gmail.com>

Since reading 4 bits always returns a value in the range [0, 15], the
check for vps_id >= HEVC_MAX_VPS_COUNT, where HEVC_MAX_VPS_COUNT = 16, is redudant.
---
 libavcodec/hevc_ps.c | 12 ++----------
 1 file changed, 2 insertions(+), 10 deletions(-)

diff --git a/libavcodec/hevc_ps.c b/libavcodec/hevc_ps.c
index abf08b919b..498467730b 100644
--- a/libavcodec/hevc_ps.c
+++ b/libavcodec/hevc_ps.c
@@ -447,11 +447,7 @@ int ff_hevc_decode_nal_vps(GetBitContext *gb, AVCodecContext *avctx,
     }
     memcpy(vps->data, gb->buffer, vps->data_size);
 
-    vps_id = get_bits(gb, 4);
-    if (vps_id >= HEVC_MAX_VPS_COUNT) {
-        av_log(avctx, AV_LOG_ERROR, "VPS id out of range: %d\n", vps_id);
-        goto err;
-    }
+    vps_id = get_bits(gb, 4); // vps_id in [0, HEVC_MAX_VPS_COUNT-1] so no check needed
 
     if (get_bits(gb, 2) != 3) { // vps_reserved_three_2bits
         av_log(avctx, AV_LOG_ERROR, "vps_reserved_three_2bits is not three\n");
@@ -882,11 +878,7 @@ int ff_hevc_parse_sps(HEVCSPS *sps, GetBitContext *gb, unsigned int *sps_id,
 
     // Coded parameters
 
-    sps->vps_id = get_bits(gb, 4);
-    if (sps->vps_id >= HEVC_MAX_VPS_COUNT) {
-        av_log(avctx, AV_LOG_ERROR, "VPS id out of range: %d\n", sps->vps_id);
-        return AVERROR_INVALIDDATA;
-    }
+    sps->vps_id = get_bits(gb, 4); // sps->vps_id in [0, HEVC_MAX_VPS_COUNT-1] so no check needed
 
     if (vps_list && !vps_list[sps->vps_id]) {
         av_log(avctx, AV_LOG_ERROR, "VPS %d does not exist\n",
-- 
2.23.0