idroqdec: Make sure a video stream has been allocated before returning packets

Reported-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
CC: libav-stable@libav.org
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/idroqdec.c

@@ -142,6 +142,8 @@ static int roq_read_packet(AVFormatContext *s,
             break;
 
         case RoQ_QUAD_CODEBOOK:
+            if (roq->video_stream_index < 0)
+                return AVERROR_INVALIDDATA;
             /* packet needs to contain both this codebook and next VQ chunk */
             codebook_offset = avio_tell(pb) - RoQ_CHUNK_PREAMBLE_SIZE;
             codebook_size = chunk_size;
@@ -191,6 +193,11 @@ static int roq_read_packet(AVFormatContext *s,
                 st->codec->block_align = st->codec->channels * st->codec->bits_per_coded_sample;
             }
         case RoQ_QUAD_VQ:
+            if (chunk_type == RoQ_QUAD_VQ) {
+                if (roq->video_stream_index < 0)
+                    return AVERROR_INVALIDDATA;
+            }
+
             /* load up the packet */
             if (av_new_packet(pkt, chunk_size + RoQ_CHUNK_PREAMBLE_SIZE))
                 return AVERROR(EIO);