shithub: libvpx

Info  •  Files  •  Log  •  Branches

vpxenc: add deterministic output option

By baking the version number into the output file, a hash of the file
will vary from commit to commit, even if the output is otherwise bit
exact. Add a -D option to suppress this behavior, for use when
bisecting or other debugging.

Change-Id: I5089a8ce5719920ffaf47620fa9069b81fa15673

--- a/vpxenc.c

+++ b/vpxenc.c

@@ -430,6 +430,8 @@

 struct EbmlGlobal

 {

+    int debug;

+

     FILE    *stream;

     uint64_t last_pts_ms;

     vpx_rational_t  framerate;

@@ -552,8 +554,10 @@

         Ebml_SerializeUnsigned(ebml, TimecodeScale, 1000000);

         Ebml_SerializeFloat(ebml, Segment_Duration,

                             ebml->last_pts_ms + frame_time);

-        Ebml_SerializeString(ebml, 0x4D80, "vpxenc" VERSION_STRING);

-        Ebml_SerializeString(ebml, 0x5741, "vpxenc" VERSION_STRING);

+        Ebml_SerializeString(ebml, 0x4D80,

+            ebml->debug ? "vpxenc" : "vpxenc" VERSION_STRING);

+        Ebml_SerializeString(ebml, 0x5741,

+            ebml->debug ? "vpxenc" : "vpxenc" VERSION_STRING);

         Ebml_EndSubElement(ebml, &startInfo);

     }

 }

@@ -740,6 +744,8 @@

 #include "args.h"

+static const arg_def_t debugmode = ARG_DEF("D", "debug", 0,

+        "Debug mode (makes output deterministic)");

 static const arg_def_t outputfile = ARG_DEF("o", "output", 1,

         "Output filename");

 static const arg_def_t use_yv12 = ARG_DEF(NULL, "yv12", 0,

@@ -774,6 +780,7 @@

         "Output IVF (default is WebM)");

 static const arg_def_t *main_args[] =

 {

+    &debugmode,

     &outputfile, &codecarg, &passes, &pass_arg, &fpf_name, &limit, &deadline,

     &best_dl, &good_dl, &rt_dl,

     &verbosearg, &psnrarg, &use_ivf, &framerate,

@@ -1052,6 +1059,8 @@

             write_webm = 0;

         else if (arg_match(&arg, &outputfile, argi))

             out_fn = arg.val;

+        else if (arg_match(&arg, &debugmode, argi))

+            ebml.debug = 1;

         else

             argj++;

     }