libavcodec/utils.c:348: error: Null Dereference
  pointer `buf` last assigned on line 338 could be null and is dereferenced at line 348, column 5.

libavcodec/utils.c:331:1: start of procedure avcodec_default_release_buffer()
329. }
330. 
331. void avcodec_default_release_buffer(AVCodecContext *s, AVFrame *pic){
     ^
332.     int i;
333.     InternalBuffer *buf, *last;

libavcodec/utils.c:335:5: 
333.     InternalBuffer *buf, *last;
334. 
335.     assert(pic->type==FF_BUFFER_TYPE_INTERNAL);
         ^
336.     assert(s->internal_buffer_count);
337. 

libavcodec/utils.c:336:5: 
334. 
335.     assert(pic->type==FF_BUFFER_TYPE_INTERNAL);
336.     assert(s->internal_buffer_count);
         ^
337. 
338.     buf = NULL; /* avoids warning */

libavcodec/utils.c:338:5: 
336.     assert(s->internal_buffer_count);
337. 
338.     buf = NULL; /* avoids warning */
         ^
339.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
340.         buf= &((InternalBuffer*)s->internal_buffer)[i];

libavcodec/utils.c:339:9: 
337. 
338.     buf = NULL; /* avoids warning */
339.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
             ^
340.         buf= &((InternalBuffer*)s->internal_buffer)[i];
341.         if(buf->data[0] == pic->data[0])

libavcodec/utils.c:339:14: Loop condition is false. Leaving loop
337. 
338.     buf = NULL; /* avoids warning */
339.     for(i=0; i<s->internal_buffer_count; i++){ //just 3-5 checks so is not worth to optimize
                  ^
340.         buf= &((InternalBuffer*)s->internal_buffer)[i];
341.         if(buf->data[0] == pic->data[0])

libavcodec/utils.c:344:5: 
342.             break;
343.     }
344.     assert(i < s->internal_buffer_count);
         ^
345.     s->internal_buffer_count--;
346.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];

libavcodec/utils.c:345:5: 
343.     }
344.     assert(i < s->internal_buffer_count);
345.     s->internal_buffer_count--;
         ^
346.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
347. 

libavcodec/utils.c:346:5: 
344.     assert(i < s->internal_buffer_count);
345.     s->internal_buffer_count--;
346.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
         ^
347. 
348.     FFSWAP(InternalBuffer, *buf, *last);

libavcodec/utils.c:348:5: 
346.     last = &((InternalBuffer*)s->internal_buffer)[s->internal_buffer_count];
347. 
348.     FFSWAP(InternalBuffer, *buf, *last);
         ^
349. 
350.     for(i=0; i<4; i++){
