fftools/ffmpeg: move closing the file into of_write_trailer()

The current code postpones closing the files until after printing the
final report, which accesses the output file size. Deal with this by
storing the final file size before closing the file.

fftools/ffmpeg.c

@@ -4312,7 +4312,6 @@ static int transcode_step(void)
 static int transcode(void)
 {
     int ret, i;
-    AVFormatContext *os;
     OutputStream *ost;
     InputStream *ist;
     int64_t timer_start;
@@ -4381,18 +4380,6 @@ static int transcode(void)
     /* dump report by using the first video and audio streams */
     print_report(1, timer_start, av_gettime_relative());
 
-    /* close the output files */
-    for (i = 0; i < nb_output_files; i++) {
-        os = output_files[i]->ctx;
-        if (os && os->oformat && !(os->oformat->flags & AVFMT_NOFILE)) {
-            if ((ret = avio_closep(&os->pb)) < 0) {
-                av_log(NULL, AV_LOG_ERROR, "Error closing file %s: %s\n", os->url, av_err2str(ret));
-                if (exit_on_error)
-                    exit_program(1);
-            }
-        }
-    }
-
     /* close each encoder */
     for (i = 0; i < nb_output_streams; i++) {
         ost = output_streams[i];

fftools/ffmpeg_mux.c

@@ -35,6 +35,7 @@
 struct Muxer {
     /* filesize limit expressed in bytes */
     int64_t limit_filesize;
+    int64_t final_filesize;
     int header_written;
 };
 
@@ -304,6 +305,17 @@ int of_write_trailer(OutputFile *of)
         return ret;
     }
 
+    of->mux->final_filesize = of_filesize(of);
+
+    if (!(of->format->flags & AVFMT_NOFILE)) {
+        ret = avio_closep(&of->ctx->pb);
+        if (ret < 0) {
+            av_log(NULL, AV_LOG_ERROR, "Error closing file %s: %s\n",
+                   of->ctx->url, av_err2str(ret));
+            return ret;
+        }
+    }
+
     return 0;
 }
 
@@ -360,7 +372,9 @@ int64_t of_filesize(OutputFile *of)
     AVIOContext *pb = of->ctx->pb;
     int64_t ret = -1;
 
-    if (pb) {
+    if (of->mux->final_filesize)
+        ret = of->mux->final_filesize;
+    else if (pb) {
         ret = avio_size(pb);
         if (ret <= 0) // FIXME improve avio_size() so it works with non seekable output too
             ret = avio_tell(pb);