[FFmpeg-devel] [PATCH]: Avoid duplicate last entry in the pass log file for the last frame

[Thierry Foucu]

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Before the patch, i was getting this in the log file:

in:131 out:131 type:2 q:1599 itex:0 ptex:9194 mv:878 misc:1710 fcode:1
bcode:1 mc-var:47056 var:132365 icount:0 skipcount:1 hbits:42;
in:132 out:132 type:2 q:1601 itex:436 ptex:9173 mv:931 misc:1706 fcode:1
bcode:1 mc-var:49302 var:137777 icount:2 skipcount:1 hbits:42;
in:133 out:133 type:2 q:1600 itex:461 ptex:6090 mv:761 misc:1622 fcode:1
bcode:1 mc-var:48901 var:133431 icount:3 skipcount:2 hbits:42;
in:134 out:134 type:2 q:1565 itex:379 ptex:14567 mv:951 misc:1749 fcode:1
bcode:1 mc-var:57528 var:134434 icount:2 skipcount:1 hbits:42;
in:135 out:135 type:1 q:1224 itex:96623 ptex:0 mv:0 misc:1007 fcode:1
bcode:1 mc-var:0 var:143173 icount:300 skipcount:0 hbits:42;
in:135 out:135 type:1 q:1224 itex:96623 ptex:0 mv:0 misc:1007 fcode:1
bcode:1 mc-var:0 var:143173 icount:300 skipcount:0 hbits:42;


With the patch, I get this:
in:131 out:131 type:2 q:1599 itex:0 ptex:9194 mv:878 misc:1710 fcode:1
bcode:1 mc-var:47056 var:132365 icount:0 skipcount:1 hbits:42;
in:132 out:132 type:2 q:1601 itex:436 ptex:9173 mv:931 misc:1706 fcode:1
bcode:1 mc-var:49302 var:137777 icount:2 skipcount:1 hbits:42;
in:133 out:133 type:2 q:1600 itex:461 ptex:6090 mv:761 misc:1622 fcode:1
bcode:1 mc-var:48901 var:133431 icount:3 skipcount:2 hbits:42;
in:134 out:134 type:2 q:1565 itex:379 ptex:14567 mv:951 misc:1749 fcode:1
bcode:1 mc-var:57528 var:134434 icount:2 skipcount:1 hbits:42;
in:135 out:135 type:1 q:1224 itex:96623 ptex:0 mv:0 misc:1007 fcode:1
bcode:1 mc-var:0 var:143173 icount:300 skipcount:0 hbits:42;

Note that before the patch the last frame stats are present twice.

It seems that at the end of encoding, we output the stats_out twice:

One at line 1254 in function do_video_out
1252                 /* if two pass, output log */
1253                 if (ost->logfile && enc->stats_out) {
1254                     fprintf(ost->logfile, "%s", enc->stats_out);
1255                 }

There is a if statement before that to make sure that the return value of
avcodec_encode_video is greater than 0

the second time we output the last frame stat is in output_packet, but we
were not checking to see if the return value of avcodec_encode_video is
greater than 0

The patch does that.

Index: ffmpeg.c
===================================================================
--- ffmpeg.c (revision 25651)
+++ ffmpeg.c (working copy)
@@ -1797,7 +1797,7 @@
                             video_size += ret;
                             if(enc->coded_frame &&
enc->coded_frame->key_frame)
                                 pkt.flags |= AV_PKT_FLAG_KEY;
-                            if (ost->logfile && enc->stats_out) {
+                            if (ost->logfile && enc->stats_out && ret > 0)
{
                                 fprintf(ost->logfile, "%s",
enc->stats_out);
                             }
                             break;
-------------- next part --------------
Index: ffmpeg.c
===================================================================
--- ffmpeg.c	(revision 25651)
+++ ffmpeg.c	(working copy)
@@ -1797,7 +1797,7 @@
                             video_size += ret;
                             if(enc->coded_frame && enc->coded_frame->key_frame)
                                 pkt.flags |= AV_PKT_FLAG_KEY;
-                            if (ost->logfile && enc->stats_out) {
+                            if (ost->logfile && enc->stats_out && ret > 0) {
                                 fprintf(ost->logfile, "%s", enc->stats_out);
                             }
                             break;