On 02/05/17 01:10, Jun Zhao wrote:
> On 2017/4/30 20:47, Mark Thompson wrote:
>> On 26/04/17 07:44, Jun Zhao wrote:
>>> From f3678e0ceb691b6df5957a2c3d26d4f0d91d4ff5 Mon Sep 17 00:00:00 2001
>>> From: Jun Zhao <jun.z...@intel.com>
>>> Date: Wed, 26 Apr 2017 14:00:56 +0800
>>> Subject: [PATCH] lavc/vaapi_encode_h265: Suppress the "above array bounds"
>>> warning.
>>> MIME-Version: 1.0
>>> Content-Type: text/plain; charset=UTF-8
>>> Content-Transfer-Encoding: 8bit
>>>
>>> setting the layer_id_included_flag lead to a potential array out of bounds,
>>> build warning message as follow:
>>> libavcodec/vaapi_encode_h265.c: In function
>>> ‘vaapi_encode_h265_write_sequence_header’:
>>> libavcodec/vaapi_encode_h265.c:305:49: warning: array subscript is above
>>> array bounds [-Warray-bounds]
>>
>> Can you explain what the aim of this is? You haven't actually set any of
>> the layer_id_included_flag in this patch, so is there more to follow dealing
>> with the layers / layer sets?
>>
>> In any case, the dimensions of the array should probably be
>> [MAX_LAYER_SETS][MAX_LAYERS] rather than the current values. (With
>> MAX_LAYER_SETS having value 1 currently, but more if you intend to add more.)
>
> Because in vaapi_encode_h265_write_vps(), when setting the
> layer_id_included_flag, the index i start from 1, it's a potential above
> array bounds issue when MAX_LAYERS == 1.
With current settings (i.e. MAX_LAYERS is 1 and vps_num_layer_sets_minus1 is 0)
none of the layer_id_included_flag are written - that code is only present now
so that the function matches the standard.
If you want to add more layers / layer sets, then indeed the constants would
need to be changed to reflect that.
>>> Signed-off-by: Jun Zhao <jun.z...@intel.com>
>>> ---
>>> libavcodec/vaapi_encode_h265.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/libavcodec/vaapi_encode_h265.c b/libavcodec/vaapi_encode_h265.c
>>> index 6e008b7b9c..1b2a49806b 100644
>>> --- a/libavcodec/vaapi_encode_h265.c
>>> +++ b/libavcodec/vaapi_encode_h265.c
>>> @@ -66,7 +66,7 @@ typedef struct VAAPIEncodeH265MiscSequenceParams {
>>> unsigned int vps_num_layer_sets_minus1;
>>> unsigned int sps_max_sub_layers_minus1;
>>> char sps_temporal_id_nesting_flag;
>>> - char layer_id_included_flag[MAX_LAYERS][64];
>>> + char layer_id_included_flag[MAX_LAYERS+1][64];
>>>
>>> // Profile/tier/level parameters.
>>> char general_profile_compatibility_flag[32];
>>> --
>>> 2.11.0
>>>
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