Added decoder_t::i_extra_picture_buffers field.

It will allow to specify the number of needed extra picture buffers due
to decoder latency.
(cherry picked from commit 74e141c5)
Signed-off-by: Jean-Baptiste Kempf <jb@videolan.org>

include/vlc_codec.h

@@ -102,6 +102,12 @@ struct decoder_t
     void            (*pf_picture_link)   ( decoder_t *, picture_t * );
     void            (*pf_picture_unlink) ( decoder_t *, picture_t * );
 
+    /**
+     * Number of extra (ie in addition to the DPB) picture buffers
+     * needed for decoding.
+     */
+    int             i_extra_picture_buffers;
+
     /* Audio output callbacks
      * XXX use decoder_NewAudioBuffer/decoder_DeleteAudioBuffer */
     aout_buffer_t  *(*pf_aout_buffer_new)( decoder_t *, int );

src/input/decoder.c

@@ -2424,7 +2424,9 @@ static picture_t *vout_new_buffer( decoder_t *p_dec )
         }
         p_vout = input_resource_RequestVout( p_owner->p_resource,
                                              p_vout, &fmt,
-                                             dpb_size + 1 + DECODER_MAX_BUFFERING_COUNT,
+                                             dpb_size +
+                                             p_dec->i_extra_picture_buffers +
+                                             1 + DECODER_MAX_BUFFERING_COUNT,
                                              true );
         vlc_mutex_lock( &p_owner->lock );
         p_owner->p_vout = p_vout;