Allow auto-detection of ljpg images.

libavformat/img2.c

@@ -284,6 +284,8 @@ static int read_header(AVFormatContext *s1, AVFormatParameters *ap)
         s->split_planes = str && !av_strcasecmp(str + 1, "y");
         st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
         st->codec->codec_id = av_str2id(img_tags, s->path);
+        if (st->codec->codec_id = CODEC_ID_LJPEG)
+            st->codec->codec_id = CODEC_ID_MJPEG;
     }
     if(st->codec->codec_type == AVMEDIA_TYPE_VIDEO && pix_fmt != PIX_FMT_NONE)
         st->codec->pix_fmt = pix_fmt;