@@ -43,6 +43,7 @@ typedef struct {

     char *video_size;       /**< Set by a private option. */

     char *framerate;        /**< Set by a private option. */

     int loop;

+    int updatefirst;

 } VideoData;

 typedef struct {

@@ -391,10 +392,11 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)

     if (!img->is_pipe) {

         if (av_get_frame_filename(filename, sizeof(filename),

-                                  img->path, img->img_number) < 0 && img->img_number==2) {

-            av_log(s, AV_LOG_WARNING,

-                   "Writing multiple frames to the same file, check the pattern '%s' if this is not what you want\n",

-                   img->path);

+                                  img->path, img->img_number) < 0 && img->img_number>1 && !img->updatefirst) {

+            av_log(s, AV_LOG_ERROR,

+                   "Could not get frame filename number %d from pattern '%s'\n",

+                   img->img_number, img->path);

+            return AVERROR(EINVAL);

         }

         for(i=0; i<3; i++){

             if (avio_open2(&pb[i], filename, AVIO_FLAG_WRITE,

@@ -461,6 +463,7 @@ static int write_packet(AVFormatContext *s, AVPacket *pkt)

 #define OFFSET(x) offsetof(VideoData, x)

 #define DEC AV_OPT_FLAG_DECODING_PARAM

+#define ENC AV_OPT_FLAG_ENCODING_PARAM

 static const AVOption options[] = {

     { "pixel_format", "", OFFSET(pixel_format), AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },

     { "video_size",   "", OFFSET(video_size),   AV_OPT_TYPE_STRING, {.str = NULL}, 0, 0, DEC },

@@ -469,6 +472,11 @@ static const AVOption options[] = {

     { NULL },

 };

+static const AVOption muxoptions[] = {

+    { "updatefirst",  "", OFFSET(updatefirst),  AV_OPT_TYPE_INT,    {.dbl = 0},    0, 1, ENC },

+    { NULL },

+};

+

 /* input */

 #if CONFIG_IMAGE2_DEMUXER

 static const AVClass img2_class = {

@@ -507,6 +515,12 @@ AVInputFormat ff_image2pipe_demuxer = {

 /* output */

 #if CONFIG_IMAGE2_MUXER

+static const AVClass img2mux_class = {

+    .class_name = "image2 muxer",

+    .item_name  = av_default_item_name,

+    .option     = muxoptions,

+    .version    = LIBAVUTIL_VERSION_INT,

+};

 AVOutputFormat ff_image2_muxer = {

     .name           = "image2",

     .long_name      = NULL_IF_CONFIG_SMALL("image2 sequence"),

@@ -516,7 +530,8 @@ AVOutputFormat ff_image2_muxer = {

     .video_codec    = CODEC_ID_MJPEG,

     .write_header   = write_header,

     .write_packet   = write_packet,

-    .flags          = AVFMT_NOTIMESTAMPS | AVFMT_NODIMENSIONS | AVFMT_NOFILE

+    .flags          = AVFMT_NOTIMESTAMPS | AVFMT_NODIMENSIONS | AVFMT_NOFILE,

+    .priv_class     = &img2mux_class,

 };

 #endif

 #if CONFIG_IMAGE2PIPE_MUXER