@@ -329,6 +329,7 @@ typedef struct AVInputFile {

     int eof_reached;      /* true if eof reached */

     int ist_index;        /* index of first stream in ist_table */

     int buffer_size;      /* current total buffer size */

+    int nb_streams;       /* nb streams we are aware of */

 } AVInputFile;

 static AVInputStream *input_streams = NULL;

@@ -1983,7 +1984,7 @@ static int transcode(AVFormatContext **output_files,

         int si = stream_maps[i].stream_index;

         if (fi < 0 || fi > nb_input_files - 1 ||

-            si < 0 || si > input_files[fi].ctx->nb_streams - 1) {

+            si < 0 || si > input_files[fi].nb_streams - 1) {

             fprintf(stderr,"Could not find input stream #%d.%d\n", fi, si);

             ret = AVERROR(EINVAL);

             goto fail;

@@ -1991,7 +1992,7 @@ static int transcode(AVFormatContext **output_files,

         fi = stream_maps[i].sync_file_index;

         si = stream_maps[i].sync_stream_index;

         if (fi < 0 || fi > nb_input_files - 1 ||

-            si < 0 || si > input_files[fi].ctx->nb_streams - 1) {

+            si < 0 || si > input_files[fi].nb_streams - 1) {

             fprintf(stderr,"Could not find sync stream #%d.%d\n", fi, si);

             ret = AVERROR(EINVAL);

             goto fail;

@@ -2607,7 +2608,7 @@ static int transcode(AVFormatContext **output_files,

         }

         /* the following test is needed in case new streams appear

            dynamically in stream : we ignore them */

-        if (pkt.stream_index >= input_files[file_index].ctx->nb_streams)

+        if (pkt.stream_index >= input_files[file_index].nb_streams)

             goto discard_packet;

         ist_index = input_files[file_index].ist_index + pkt.stream_index;

         ist = &input_streams[ist_index];

@@ -3365,6 +3366,7 @@ static int opt_input_file(const char *opt, const char *filename)

     input_files = grow_array(input_files, sizeof(*input_files), &nb_input_files, nb_input_files + 1);

     input_files[nb_input_files - 1].ctx        = ic;

     input_files[nb_input_files - 1].ist_index  = nb_input_streams - ic->nb_streams;

+    input_files[nb_input_files - 1].nb_streams = ic->nb_streams;

     frame_rate    = (AVRational){0, 0};

     frame_pix_fmt = PIX_FMT_NONE;