New "copytb" ffmpeg cli option to copy input stream time base when stream copying.

This should avoid non monotone timestamps for video streams with vfr.

Originally committed as revision 26340 to svn://svn.ffmpeg.org/ffmpeg/trunk

ffmpeg.c

@@ -213,6 +213,7 @@ static int video_sync_method= -1;
 static int audio_sync_method= 0;
 static float audio_drift_threshold= 0.1;
 static int copy_ts= 0;
+static int copy_tb;
 static int opt_shortest = 0;
 static int video_global_header = 0;
 static char *vstats_filename;
@@ -2143,7 +2144,7 @@ static int transcode(AVFormatContext **output_files,
                 goto fail;
             memcpy(codec->extradata, icodec->extradata, icodec->extradata_size);
             codec->extradata_size= icodec->extradata_size;
-            if(av_q2d(icodec->time_base)*icodec->ticks_per_frame > av_q2d(ist->st->time_base) && av_q2d(ist->st->time_base) < 1.0/1000){
+            if(!copy_tb && av_q2d(icodec->time_base)*icodec->ticks_per_frame > av_q2d(ist->st->time_base) && av_q2d(ist->st->time_base) < 1.0/1000){
                 codec->time_base = icodec->time_base;
                 codec->time_base.num *= icodec->ticks_per_frame;
                 av_reduce(&codec->time_base.num, &codec->time_base.den,
@@ -4214,6 +4215,7 @@ static const OptionDef options[] = {
     { "adrift_threshold", HAS_ARG | OPT_FLOAT | OPT_EXPERT, {(void*)&audio_drift_threshold}, "audio drift threshold", "threshold" },
     { "vglobal", HAS_ARG | OPT_INT | OPT_EXPERT, {(void*)&video_global_header}, "video global header storage type", "" },
     { "copyts", OPT_BOOL | OPT_EXPERT, {(void*)&copy_ts}, "copy timestamps" },
+    { "copytb", OPT_BOOL | OPT_EXPERT, {(void*)&copy_tb}, "copy input stream time base when stream copying" },
     { "shortest", OPT_BOOL | OPT_EXPERT, {(void*)&opt_shortest}, "finish encoding within shortest input" }, //
     { "dts_delta_threshold", HAS_ARG | OPT_FLOAT | OPT_EXPERT, {(void*)&dts_delta_threshold}, "timestamp discontinuity delta threshold", "threshold" },
     { "programid", HAS_ARG | OPT_INT | OPT_EXPERT, {(void*)&opt_programid}, "desired program number", "" },