ffmpeg: rescue poor abused limit_filesize global.

Keep a per-OutputFile instance of it, thus making -fs work with multiple
output files.
Signed-off-by: Alex Converse <alex.converse@gmail.com>

ffmpeg.c

@@ -216,7 +216,7 @@ static int64_t extra_size = 0;
 static int nb_frames_dup = 0;
 static int nb_frames_drop = 0;
 static int input_sync;
-static uint64_t limit_filesize = 0;
+static uint64_t limit_filesize = UINT64_MAX;
 static int force_fps = 0;
 static char *forced_key_frames = NULL;
 
@@ -328,6 +328,7 @@ typedef struct OutputFile {
     int ost_index;       /* index of the first stream in output_streams */
     int64_t recording_time; /* desired length of the resulting file in microseconds */
     int64_t start_time;     /* start time in microseconds */
+    uint64_t limit_filesize;
 } OutputFile;
 
 static InputStream *input_streams = NULL;
@@ -2377,12 +2378,15 @@ static int transcode(OutputFile *output_files,
            smallest output pts */
         file_index = -1;
         for (i = 0; i < nb_output_streams; i++) {
+            OutputFile *of;
             int64_t ipts;
             double  opts;
             ost = &output_streams[i];
+            of = &output_files[ost->file_index];
             os = output_files[ost->file_index].ctx;
             ist = &input_streams[ost->source_index];
-            if(ost->is_past_recording_time || no_packet[ist->file_index])
+            if (ost->is_past_recording_time || no_packet[ist->file_index] ||
+                (os->pb && avio_tell(os->pb) >= of->limit_filesize))
                 continue;
                 opts = ost->st->pts.val * av_q2d(ost->st->time_base);
             ipts = ist->pts;
@@ -2412,10 +2416,6 @@ static int transcode(OutputFile *output_files,
             break;
         }
 
-        /* finish if limit size exhausted */
-        if (limit_filesize != 0 && limit_filesize <= avio_tell(output_files[0].ctx->pb))
-            break;
-
         /* read a frame from it and output it in the fifo */
         is = input_files[file_index].ctx;
         ret= av_read_frame(is, &pkt);
@@ -3732,6 +3732,7 @@ static int opt_output_file(const char *opt, const char *filename)
     output_files[nb_output_files - 1].ost_index = nb_output_streams - oc->nb_streams;
     output_files[nb_output_files - 1].recording_time = recording_time;
     output_files[nb_output_files - 1].start_time     = start_time;
+    output_files[nb_output_files - 1].limit_filesize = limit_filesize;
     av_dict_copy(&output_files[nb_output_files - 1].opts, format_opts, 0);
 
     /* check filename in case of an image number is expected */
@@ -3863,6 +3864,7 @@ static int opt_output_file(const char *opt, const char *filename)
     chapters_input_file = INT_MAX;
     recording_time = INT64_MAX;
     start_time     = 0;
+    limit_filesize = UINT64_MAX;
 
     av_freep(&meta_data_maps);
     nb_meta_data_maps = 0;