[Ffmpeg-devel] [patch] h264.c, dont go beyond buffer in h264_decode_nal_unit

[Mean]

Michael Niedermayer wrote:
>
>> Index: h264.c
>> ===================================================================
>> --- h264.c	(revision 2980)
>> +++ h264.c	(working copy)
>> @@ -8075,16 +8075,21 @@
>>          int i, nalsize = 0;
>>  
>>        if(h->is_avc) {
>>     
>
>   
>> -        if(buf_index >= buf_size) break;
>> +        if(buf_index==buf_size) break;
>>     
>
> how can these differ?
>
>   
Ok

>   
>> +        if(buf_index +h->nal_length_size>= buf_size) 
>> +        {
>>     
>
> { placement missmatches the rest of the file
> also this check is unneeded the buffer is a few bytes larger
> and nal_length_size is limited to 2 or 4
>
>
>   
    I'm under the impression that buf_size in most cases is given by the 
user application alongside the buffer itself.
    It is likely to hold a few bytes more, but how can one be sure ?

    In my case, there was 3 extra bytess and nal_length_size=4, so one 
extra byte was read from buffer (?).

    Thanks