hls: Reset the AVIOContext when seeking

This avoids reading any old data in the AVIOContext buffer after
the seek, and indicates to the mpegts demuxer that we've seeked,
avoiding continuity check errors.
Signed-off-by: NMartin Storsjö <martin@martin.st>

libavformat/hls.c

@@ -708,6 +708,10 @@ static int hls_read_seek(AVFormatContext *s, int stream_index,
         av_free_packet(&var->pkt);
         reset_packet(&var->pkt);
         var->pb.eof_reached = 0;
+        /* Clear any buffered data */
+        var->pb.buf_end = var->pb.buf_ptr = var->pb.buffer;
+        /* Reset the pos, to let the mpegts demuxer know we've seeked. */
+        var->pb.pos = 0;
 
         /* Locate the segment that contains the target timestamp */
         for (j = 0; j < var->n_segments; j++) {