scripts/NHMLFixup.lua

   1 #!/usr/bin/env lua
   2 ----------------------------------------------------------------------------------------------------------------------
   3 ----------------------------------------------------------------------------------------------------------------------
   4 -- NHMLFixup v8 by Ilari (2010-12-06).
   5 -- Update timecodes in NHML Audio/Video track timing to conform to given MKV v2 timecodes file.
   6 -- Syntax: NHMLFixup <video-nhml-file> <audio-nhml-file> <mkv-timecodes-file> [delay=<delay>] [tvaspect]
   7 -- <delay> is number of milliseconds to delay the video (in order to compensate for audio codec delay, reportedly
   8 -- does not work right with some demuxers).
   9 -- The 'tvaspect' option makes video track to be automatically adjusted to '4:3' aspect ratio.
  10 --
  11 -- Version v8 by Ilari (2010-12-06):
  12 --      - Support Special timecode file "@CFR" that fixes up audio for CFR encode.
  13 --
  14 -- Version v7 by Ilari (2010-10-24):
  15 --      - Fix bug in time division (use integer timestamps, not decimal ones).
  16 --
  17 -- Version v6 by Ilari (2010-10-24):
  18 --      - Make it work on Lua 5.2 (work 4).
  19 --
  20 -- Version v5 by Ilari (2010-09-18):
  21 --      - Move the files first out of way, since rename-over fails on Windows.
  22 --
  23 -- Version v4 by Ilari (2010-09-17):
  24 --      - Change audio track ID if it collides with video track..
  25 --
  26 -- Version v3 by Ilari (2010-09-17):
  27 --      - Support setting aspect ratio correction.
  28 --
  29 -- Version v2 by Ilari (2010-09-16):
  30 --      - If sound and video NHMLs are wrong way around, automatically swap them.
  31 --      - Check that one of the NHMLs is sound and other is video.
  32 --
  33 ----------------------------------------------------------------------------------------------------------------------
  34 ----------------------------------------------------------------------------------------------------------------------
  35
  36 --Lua 5.2 fix:
  37 unpack = unpack or table.unpack;
  38
  39 ----------------------------------------------------------------------------------------------------------------------
  40 -- Function reduce_fraction(number numerator, number denumerator)
  41 -- Returns reduced fraction.
  42 ----------------------------------------------------------------------------------------------------------------------
  43 reduce_fraction = function(numerator, denumerator)
  44         local x, y = numerator, denumerator;
  45         while y > 0 do
  46                 x, y = y, x % y;
  47         end
  48         return numerator / x, denumerator / x;
  49 end
  50
  51 ----------------------------------------------------------------------------------------------------------------------
  52 -- Function load_timecode_file(FILE file, number timescale)
  53 -- Loads timecode data from file @file, using timescale of @timescale frames per second. Returns array of scaled
  54 -- timecodes.
  55 ----------------------------------------------------------------------------------------------------------------------
  56 load_timecode_file = function(file, timescale)
  57         local line, ret;
  58         line = file:read("*l");
  59         if line ~= "# timecode format v2" then
  60                 error("Timecode file is not in MKV timecodes v2 format");
  61         end
  62         ret = {};
  63         while true do
  64                 line = file:read("*l");
  65                 if not line then
  66                         break;
  67                 end
  68                 local timecode = tonumber(line);
  69                 if not timecode then
  70                         error("Can't parse timecode '" .. line .. "'.");
  71                 end
  72                 table.insert(ret, math.floor(0.5 + timecode / 1000 * timescale));
  73         end
  74         return ret;
  75 end
  76
  77 ----------------------------------------------------------------------------------------------------------------------
  78 -- Function make_reverse_index_table(Array array)
  79 -- Returns table, that has entry for each entry in given array @array with value being rank of value, 1 being smallest
  80 -- and #array the largest. If @lookup is non-nil, values are looked up from that array.
  81 ----------------------------------------------------------------------------------------------------------------------
  82 make_reverse_index_table = function(array, lookup)
  83         local sorted, ret;
  84         local i;
  85         sorted = {};
  86         for i = 1,#array do
  87                 sorted[i] = array[i];
  88         end
  89         table.sort(sorted);
  90         ret = {};
  91         for i = 1,#sorted do
  92                 ret[sorted[i]] = (lookup and lookup[i]) or i;
  93         end
  94         return ret;
  95 end
  96
  97 ----------------------------------------------------------------------------------------------------------------------
  98 -- Function max_causality_violaton(Array CTS, Array DTS)
  99 -- Return the maximum number of time units CTS and DTS values violate causality. #CTS must equal #DTS.
 100 ----------------------------------------------------------------------------------------------------------------------
 101 max_causality_violation = function(CTS, DTS)
 102         local max_cv = 0;
 103         local i;
 104         for i = 1,#CTS do
 105                 max_cv = math.max(max_cv, DTS[i] - CTS[i]);
 106         end
 107         return max_cv;
 108 end
 109
 110 ----------------------------------------------------------------------------------------------------------------------
 111 -- Function fixup_video_times(Array sampledata, Array timecodes, Number spec_delay)
 112 -- Fixes video timing of @sampledata (fields CTS and DTS) to be consistent with timecodes in @timecodes. Returns the
 113 -- CTS offset of first sample (for fixing audio). @spec_delay is special delay to add (to fix A/V sync).
 114 ----------------------------------------------------------------------------------------------------------------------
 115 fixup_video_times = function(sampledata, timecodes, spec_delay)
 116         local cts_tab = {};
 117         local dts_tab = {};
 118         local k, v, i;
 119
 120         if not timecodes then
 121                 local min_cts = 999999999999999999999;
 122                 for i = 1,#sampledata do
 123                         --Maximum causality violation is always zero in valid HHML.
 124                         sampledata[i].CTS = sampledata[i].CTS + spec_delay;
 125                         --Spec_delay should not apply to audio.
 126                         min_cts = math.min(min_cts, sampledata[i].CTS - spec_delay);
 127                 end
 128                 return min_cts;
 129         end
 130
 131         if #sampledata ~= #timecodes then
 132                 error("Number of samples (" .. #sampledata .. ") does not match number of timecodes (" .. #timecodes
 133                         .. ").");
 134         end
 135         for i = 1,#sampledata do
 136                 cts_tab[i] = sampledata[i].CTS;
 137                 dts_tab[i] = sampledata[i].DTS;
 138         end
 139         cts_lookup = make_reverse_index_table(cts_tab, timecodes);
 140         dts_lookup = make_reverse_index_table(dts_tab, timecodes);
 141
 142         -- Perform time translation and find max causality violation.
 143         local max_cv = 0;
 144         for i = 1,#sampledata do
 145                 sampledata[i].CTS = cts_lookup[sampledata[i].CTS];
 146                 sampledata[i].DTS = dts_lookup[sampledata[i].DTS];
 147                 max_cv = math.max(max_cv, sampledata[i].DTS - sampledata[i].CTS);
 148         end
 149         -- Add maximum causality violation to CTS to eliminate the causality violations.
 150         -- Also find the minimum CTS.
 151         local min_cts = 999999999999999999999;
 152         for i = 1,#sampledata do
 153                 sampledata[i].CTS = sampledata[i].CTS + max_cv + spec_delay;
 154                 --Spec_delay should not apply to audio.
 155                 min_cts = math.min(min_cts, sampledata[i].CTS - spec_delay);
 156         end
 157         return min_cts;
 158 end
 159
 160 ----------------------------------------------------------------------------------------------------------------------
 161 -- Function fixup_video_times(Array sampledata, Number min_video_cts, Number video_timescale, Number audio_timescale)
 162 -- Fixes video timing of @sampledata (field CTS) to be consistent with video minimum CTS of @cts. Video timescale
 163 -- is assumed to be @video_timescale and audio timescale @audio_timescale.
 164 ----------------------------------------------------------------------------------------------------------------------
 165 fixup_audio_times = function(sampledata, min_video_cts, video_timescale, audio_timescale)
 166         local fixup = math.floor(0.5 + min_video_cts * audio_timescale / video_timescale);
 167         for i = 1,#sampledata do
 168                 sampledata[i].CTS = sampledata[i].CTS + fixup;
 169         end
 170 end
 171
 172 ----------------------------------------------------------------------------------------------------------------------
 173 -- Function translate_NHML_TS_in(Array sampledata);
 174 -- Translate NHML CTSOffset fields in @sampledata into CTS fields.
 175 ----------------------------------------------------------------------------------------------------------------------
 176 translate_NHML_TS_in = function(sampledata, default_dDTS)
 177         local i;
 178         local dts = 0;
 179         for i = 1,#sampledata do
 180                 if not sampledata[i].DTS then
 181                         sampledata[i].DTS = dts + default_dDTS;
 182                 end
 183                 dts = sampledata[i].DTS;
 184                 if sampledata[i].CTSOffset then
 185                         sampledata[i].CTS = sampledata[i].CTSOffset + sampledata[i].DTS;
 186                 else
 187                         sampledata[i].CTS = sampledata[i].DTS;
 188                 end
 189         end
 190 end
 191
 192 ----------------------------------------------------------------------------------------------------------------------
 193 -- Function translate_NHML_TS_out(Array sampledata);
 194 -- Translate CTS fields in @sampledata into NHML CTSOffset fields.
 195 ----------------------------------------------------------------------------------------------------------------------
 196 translate_NHML_TS_out = function(sampledata)
 197         local i;
 198         for i = 1,#sampledata do
 199                 sampledata[i].CTSOffset = sampledata[i].CTS - sampledata[i].DTS;
 200                 if sampledata[i].CTSOffset < 0 then
 201                         error("INTERNAL ERROR: translate_NHML_TS_out: Causality violation: CTS=" .. tostring(
 202                                 sampledata[i].CTS) .. " DTS=" .. tostring(sampledata[i].DTS) .. ".");
 203                 end
 204                 sampledata[i].CTS = nil;
 205         end
 206 end
 207
 208 ----------------------------------------------------------------------------------------------------------------------
 209 -- Function map_table_to_number(Table tab);
 210 -- Translate all numeric fields in table @tab into numbers.
 211 ----------------------------------------------------------------------------------------------------------------------
 212 map_table_to_number = function(tab)
 213         local k, v;
 214         for k, v in pairs(tab) do
 215                 local n = tonumber(v);
 216                 if n then
 217                         tab[k] = n;
 218                 end
 219         end
 220 end
 221
 222 ----------------------------------------------------------------------------------------------------------------------
 223 -- Function map_fields_to_number(Array sampledata);
 224 -- Translate all numeric fields in array @sampledata into numbers.
 225 ----------------------------------------------------------------------------------------------------------------------
 226 map_fields_to_number = function(sampledata)
 227         local i;
 228         for i = 1,#sampledata do
 229                 map_table_to_number(sampledata[i]);
 230         end
 231 end
 232
 233 ----------------------------------------------------------------------------------------------------------------------
 234 -- Function escape_xml_text(String str)
 235 -- Return XML escaping of text str.
 236 ----------------------------------------------------------------------------------------------------------------------
 237 escape_xml_text = function(str)
 238         str = string.gsub(str, "&", "&amp;");
 239         str = string.gsub(str, "<", "&lt;");
 240         str = string.gsub(str, ">", "&gt;");
 241         str = string.gsub(str, "\"", "&quot;");
 242         str = string.gsub(str, "\'", "&apos;");
 243         return str;
 244 end
 245
 246 ----------------------------------------------------------------------------------------------------------------------
 247 -- Function escape_xml_text(String str)
 248 -- Return XML unescaping of text str.
 249 ----------------------------------------------------------------------------------------------------------------------
 250 unescape_xml_text = function(str)
 251         str = string.gsub(str, "&apos;", "\'");
 252         str = string.gsub(str, "&quot;", "\"");
 253         str = string.gsub(str, "&gt;", ">");
 254         str = string.gsub(str, "&lt;", "<");
 255         str = string.gsub(str, "&amp;", "&");
 256         return str;
 257 end
 258
 259 ----------------------------------------------------------------------------------------------------------------------
 260 -- Function serialize_table_to_xml_entity(File file, String tag, Table data, bool noclose);
 261 -- Write @data as XML start tag of type @tag into @file. If noclose is true, then tag will not be closed.
 262 ----------------------------------------------------------------------------------------------------------------------
 263 serialize_table_to_xml_entity = function(file, tag, data, noclose)
 264         local k, v;
 265         file:write("<" .. tag .. " ");
 266         for k, v in pairs(data) do
 267                 file:write(k .. "=\"" .. escape_xml_text(tostring(v)) .. "\" ");
 268         end
 269         if noclose then
 270                 file:write(">\n");
 271         else
 272                 file:write("/>\n");
 273         end
 274 end
 275
 276 ----------------------------------------------------------------------------------------------------------------------
 277 -- Function serialize_array_to_xml_entity(File file, String tag, Array data);
 278 -- Write each element of @data as empty XML tag of type @tag into @file.
 279 ----------------------------------------------------------------------------------------------------------------------
 280 serialize_array_to_xml_entity = function(file, tag, data)
 281         local i;
 282         for i = 1,#data do
 283                 serialize_table_to_xml_entity(file, tag, data[i]);
 284         end
 285 end
 286
 287 ----------------------------------------------------------------------------------------------------------------------
 288 -- Function write_NHML_data(File file, Table header, Table sampledata)
 289 -- Write entiere NHML file.
 290 ----------------------------------------------------------------------------------------------------------------------
 291 write_NHML_data = function(file, header, sampledata)
 292         file:write("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n");
 293         serialize_table_to_xml_entity(file, "NHNTStream", header, true);
 294         serialize_array_to_xml_entity(file, "NHNTSample", sampledata);
 295         file:write("</NHNTStream>\n");
 296 end
 297
 298 ----------------------------------------------------------------------------------------------------------------------
 299 -- Function open_file_checked(String file, String mode, bool for_write)
 300 -- Return file handle to file (checking that open succeeds).
 301 ----------------------------------------------------------------------------------------------------------------------
 302 open_file_checked = function(file, mode, for_write)
 303         local a, b;
 304         a, b = io.open(file, mode);
 305         if not a then
 306                 error("Can't open '" .. file .. "': " .. b);
 307         end
 308         return a;
 309 end
 310
 311 ----------------------------------------------------------------------------------------------------------------------
 312 -- Function call_with_file(fun, string file, String mode, ...);
 313 -- Call fun with opened file handle to @file (in mode @mode) as first parameter.
 314 ----------------------------------------------------------------------------------------------------------------------
 315 call_with_file = function(fun, file, mode, ...)
 316         -- FIXME: Handle nils returned from function.
 317         local handle = open_file_checked(file, mode);
 318         local ret = {fun(handle, ...)};
 319         handle:close();
 320         return unpack(ret);
 321 end
 322
 323 ----------------------------------------------------------------------------------------------------------------------
 324 -- Function xml_parse_tag(String line);
 325 -- Returns the xml tag type for @line plus table of attributes.
 326 ----------------------------------------------------------------------------------------------------------------------
 327 xml_parse_tag = function(line)
 328         -- More regexping...
 329         local tagname;
 330         local attr = {};
 331         tagname = string.match(line, "<(%S+).*>");
 332         if not tagname then
 333                 error("'" .. line .. "': Parse error.");
 334         end
 335         local k, v;
 336         for k, v in string.gmatch(line, "([^ =]+)=\"([^\"]*)\"") do
 337                 attr[k] = unescape_xml_text(v);
 338         end
 339         return tagname, attr;
 340 end
 341
 342 ----------------------------------------------------------------------------------------------------------------------
 343 -- Function load_NHML(File file)
 344 -- Loads NHML file @file. Returns header table and samples array.
 345 ----------------------------------------------------------------------------------------------------------------------
 346 load_NHML = function(file)
 347         -- Let's regexp this shit...
 348         local header = {};
 349         local samples = {};
 350         while true do
 351                 local line = file:read();
 352                 if not line then
 353                         error("Unexpected end of NHML file.");
 354                 end
 355                 local xtag, attributes;
 356                 xtag, attributes = xml_parse_tag(line);
 357                 if xtag == "NHNTStream" then
 358                         header = attributes;
 359                 elseif xtag == "NHNTSample" then
 360                         table.insert(samples, attributes);
 361                 elseif xtag == "/NHNTStream" then
 362                         break;
 363                 elseif xtag == "?xml" then
 364                 else
 365                         print("WARNING: Unrecognized tag '" .. xtag .. "'.");
 366                 end
 367         end
 368         return header, samples;
 369 end
 370
 371 ----------------------------------------------------------------------------------------------------------------------
 372 -- Function reame_errcheck(String old, String new)
 373 -- Rename old to new. With error checking.
 374 ----------------------------------------------------------------------------------------------------------------------
 375 rename_errcheck = function(old, new, backup)
 376         local a, b;
 377         os.remove(backup);
 378         a, b = os.rename(new, backup);
 379         if not a then
 380                 error("Can't rename '" .. new .. "' -> '" .. backup .. "': " .. b);
 381         end
 382         a, b = os.rename(old, new);
 383         if not a then
 384                 error("Can't rename '" .. old .. "' -> '" .. new .. "': " .. b);
 385         end
 386 end
 387
 388 ----------------------------------------------------------------------------------------------------------------------
 389 -- Function compute_max_div(Integer ctsBound, Integer timescale, Integer maxCode, pictureOffset)
 390 -- Compute maximum allowable timescale.
 391 ----------------------------------------------------------------------------------------------------------------------
 392 compute_max_div = function(ctsBound, timeScale, maxCode, pictureOffset)
 393         -- Compute the logical number of frames.
 394         local logicalFrames = ctsBound / pictureOffset;
 395         local maxNumerator = math.floor(maxCode / logicalFrames);
 396         -- Be conservative and assume numerator is rounded up. That is, solve the biggest maxdiv such that for all
 397         -- 1 <= x <= maxdiv, maxNumerator >= ceil(x * pictureOffset / timeScale) is true.
 398         -- Since maxNumerator is integer, this is equivalent to:
 399         -- maxNumerator >= x * pictureOffset / timeScale
 400         -- => maxNumerator * timeScale / pictureOffset >= x, thus
 401         -- maxDiv = math.floor(maxNumerator * timeScale / pictureOffset);
 402         return math.floor(maxNumerator * timeScale / pictureOffset);
 403 end
 404
 405 ----------------------------------------------------------------------------------------------------------------------
 406 -- Function rational_approximate(Integer origNum, Integer origDenum, Integer maxDenum)
 407 -- Approximate origNum / origDenum using rational with maximum denumerator of maxDenum
 408 ----------------------------------------------------------------------------------------------------------------------
 409 rational_approximate = function(origNum, origDenum, maxDenum)
 410         -- FIXME: Better approximations are possible.
 411         local div = math.ceil(origDenum / maxDenum);
 412         return math.floor(0.5 + origNum / div), math.floor(0.5 + origDenum / div);
 413 end
 414
 415 ----------------------------------------------------------------------------------------------------------------------
 416 -- Function fixup_mp4box_bug_cfr(Table header, Table samples, Integer pictureOffset, Integer maxdiv)
 417 -- Fix MP4Box timecode bug for CFR video by approximating the framerate a bit.
 418 ----------------------------------------------------------------------------------------------------------------------
 419 fixup_mp4box_bug_cfr = function(header, samples, pictureOffset, maxdiv)
 420         local oNum, oDenum;
 421         local nNum, nDenum;
 422         local i;
 423         oNum, oDenum = pictureOffset, header.timeScale;
 424         nNum, nDenum = rational_approximate(oNum, oDenum, maxdiv);
 425         header.timeScale = nDenum;
 426         for i = 1, #samples do
 427                 samples[i].DTS = math.floor(0.5 + samples[i].DTS / oNum * nNum);
 428                 samples[i].CTS = math.floor(0.5 + samples[i].CTS / oNum * nNum);
 429         end
 430 end
 431
 432
 433 if #arg < 3 then
 434         error("Syntax: NHMLFixup.lua <video.nhml> <audio.nhml> <timecodes.txt> [delay=<delay>] [tvaspect]");
 435 end
 436
 437 -- Load the NHML files.
 438 io.stdout:write("Loading '" .. arg[1] .. "'..."); io.stdout:flush();
 439 video_header, video_samples = call_with_file(load_NHML, arg[1], "r");
 440 io.stdout:write("Done.\n");
 441 io.stdout:write("Loading '" .. arg[2] .. "'..."); io.stdout:flush();
 442 audio_header, audio_samples = call_with_file(load_NHML, arg[2], "r");
 443 io.stdout:write("Done.\n");
 444 io.stdout:write("String to number conversion on video header..."); io.stdout:flush();
 445 map_table_to_number(video_header);
 446 io.stdout:write("Done.\n");
 447 io.stdout:write("String to number conversion on video samples..."); io.stdout:flush();
 448 map_fields_to_number(video_samples);
 449 io.stdout:write("Done.\n");
 450 io.stdout:write("String to number conversion on audio header..."); io.stdout:flush();
 451 map_table_to_number(audio_header);
 452 io.stdout:write("Done.\n");
 453 io.stdout:write("String to number conversion on audio samples..."); io.stdout:flush();
 454 map_fields_to_number(audio_samples);
 455 io.stdout:write("Done.\n");
 456 if video_header.streamType == 4 and audio_header.streamType == 5 then
 457         -- Ok.
 458 elseif video_header.streamType == 5 and audio_header.streamType == 4 then
 459         print("WARNING: You got audio and video wrong way around. Swapping them for you...");
 460         audio_header,audio_samples,arg[2],video_header,video_samples,arg[1] =
 461                 video_header,video_samples,arg[1],audio_header,audio_samples,arg[2];
 462 else
 463         error("Expected one video track and one audio track");
 464 end
 465
 466 if video_header.trackID == audio_header.trackID then
 467         print("WARNING: Audio and video have the same track id. Assigning new track id to audio track...");
 468         audio_header.trackID = audio_header.trackID + 1;
 469 end
 470
 471 io.stdout:write("Computing CTS for video samples..."); io.stdout:flush();
 472 translate_NHML_TS_in(video_samples, video_header.DTS_increment or 0);
 473 io.stdout:write("Done.\n");
 474 io.stdout:write("Computing CTS for audio samples..."); io.stdout:flush();
 475 translate_NHML_TS_in(audio_samples, audio_header.DTS_increment or 0);
 476 io.stdout:write("Done.\n");
 477
 478 -- Alter timescale if needed and load the timecode data.
 479 delay = 0;
 480 rdelay = 0;
 481 for i = 4,#arg do
 482         if arg[i] == "tvaspect" then
 483                 do_aspect_fixup = true;
 484         elseif string.sub(arg[i], 1, 6) == "delay=" then
 485                 local n = tonumber(string.sub(arg[i], 7, #(arg[i])));
 486                 if not n then
 487                         error("Bad delay.");
 488                 end
 489                 rdelay = n;
 490                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 491         end
 492 end
 493
 494
 495 MAX_MP4BOX_TIMECODE = 0x7FFFFFF;
 496 if arg[3] ~= "@CFR" then
 497         timecode_data = call_with_file(load_timecode_file, arg[3], "r", video_header.timeScale);
 498         if timecode_data[#timecode_data] > MAX_MP4BOX_TIMECODE then
 499                 -- Workaround MP4Box bug.
 500                 divider = math.ceil(timecode_data[#timecode_data] / MAX_MP4BOX_TIMECODE);
 501                 print("Notice: Dividing timecodes by " .. divider .. " to workaround MP4Box timecode bug.");
 502                 io.stdout:write("Performing division..."); io.stdout:flush();
 503                 video_header.timeScale = math.floor(0.5 + video_header.timeScale / divider);
 504                 for i = 1,#timecode_data do
 505                         timecode_data[i] = math.floor(0.5 + timecode_data[i] / divider);
 506                 end
 507                 --Recompute delay.
 508                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 509                 io.stdout:write("Done.\n");
 510         end
 511 else
 512         timecode_data = nil;
 513         local maxCTS = 0;
 514         local i;
 515         local DTSOffset = (video_samples[2] or video_samples[1]).DTS - video_samples[1].DTS;
 516         if DTSOffset == 0 then
 517                 DTSOffset = 1;
 518         end
 519         for i = 1,#video_samples do
 520                 if video_samples[i].CTS > maxCTS then
 521                         maxCTS = video_samples[i].CTS;
 522                 end
 523                 if video_samples[i].DTS % DTSOffset ~= 0 then
 524                         error("Video is not CFR");
 525                 end
 526                 if (video_samples[i].CTS - video_samples[1].CTS) % DTSOffset ~= 0 then
 527                         error("Video is not CFR");
 528                 end
 529         end
 530         if video_samples[#video_samples].CTS > MAX_MP4BOX_TIMECODE then
 531                 --Workaround MP4Box bug.
 532                 local maxdiv = compute_max_div(maxCTS, video_header.timeScale, MAX_MP4BOX_TIMECODE, DTSOffset);
 533                 print("Notice: Restricting denumerator to " .. maxdiv .. " to workaround MP4Box timecode bug.");
 534                 io.stdout:write("Fixing timecodes..."); io.stdout:flush();
 535                 fixup_mp4box_bug_cfr(video_header, video_samples, DTSOffset, maxdiv);
 536                 --Recompute delay.
 537                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 538                 io.stdout:write("Done.\n");
 539         end
 540 end
 541
 542 -- Do the actual fixup.
 543 io.stdout:write("Fixing up video timecodes..."); io.stdout:flush();
 544 audio_fixup = fixup_video_times(video_samples, timecode_data, delay);
 545 io.stdout:write("Done.\n");
 546 io.stdout:write("Fixing up audio timecodes..."); io.stdout:flush();
 547 fixup_audio_times(audio_samples, audio_fixup, video_header.timeScale, audio_header.timeScale);
 548 io.stdout:write("Done.\n");
 549
 550 if do_aspect_fixup then
 551         video_header.parNum, video_header.parDen = reduce_fraction(4 * video_header.height, 3 * video_header.width);
 552 end
 553
 554 -- Save the NHML files.
 555 io.stdout:write("Computing CTSOffset for video samples..."); io.stdout:flush();
 556 translate_NHML_TS_out(video_samples);
 557 io.stdout:write("Done.\n");
 558 io.stdout:write("Computing CTSOffset for audio samples..."); io.stdout:flush();
 559 translate_NHML_TS_out(audio_samples);
 560 io.stdout:write("Done.\n");
 561 io.stdout:write("Saving '" .. arg[1] .. ".tmp'..."); io.stdout:flush();
 562 call_with_file(write_NHML_data, arg[1] .. ".tmp", "w", video_header, video_samples);
 563 io.stdout:write("Done.\n");
 564 io.stdout:write("Saving '" .. arg[2] .. ".tmp'..."); io.stdout:flush();
 565 call_with_file(write_NHML_data, arg[2] .. ".tmp", "w", audio_header, audio_samples);
 566 io.stdout:write("Done.\n");
 567 io.stdout:write("Renaming '" .. arg[1] .. ".tmp' -> '" .. arg[1] .. "'..."); io.stdout:flush();
 568 rename_errcheck(arg[1] .. ".tmp", arg[1], arg[1] .. ".bak");
 569 io.stdout:write("Done.\n");
 570 io.stdout:write("Renaming '" .. arg[2] .. ".tmp' -> '" .. arg[2] .. "'..."); io.stdout:flush();
 571 rename_errcheck(arg[2] .. ".tmp", arg[2], arg[2] .. ".bak");
 572 io.stdout:write("Done.\n");
 573 io.stdout:write("All done.\n");