scripts/NHMLFixup.lua

   1 #!/usr/bin/env lua
   2 ----------------------------------------------------------------------------------------------------------------------
   3 ----------------------------------------------------------------------------------------------------------------------
   4 -- NHMLFixup v9 by Ilari (2011-04-01).
   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|widescreen]
   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 -- The 'widescreen' option makes video track to be automatically adjusted to '16:9' aspect ratio.
  11 --
  12 -- Version v9 by Ilari (2011-04-01):
  13 --      - Support widescreen mode ("widescreen").
  14 --
  15 -- Version v8 by Ilari (2010-12-06):
  16 --      - Support Special timecode file "@CFR" that fixes up audio for CFR encode.
  17 --
  18 -- Version v7 by Ilari (2010-10-24):
  19 --      - Fix bug in time division (use integer timestamps, not decimal ones).
  20 --
  21 -- Version v6 by Ilari (2010-10-24):
  22 --      - Make it work on Lua 5.2 (work 4).
  23 --
  24 -- Version v5 by Ilari (2010-09-18):
  25 --      - Move the files first out of way, since rename-over fails on Windows.
  26 --
  27 -- Version v4 by Ilari (2010-09-17):
  28 --      - Change audio track ID if it collides with video track..
  29 --
  30 -- Version v3 by Ilari (2010-09-17):
  31 --      - Support setting aspect ratio correction.
  32 --
  33 -- Version v2 by Ilari (2010-09-16):
  34 --      - If sound and video NHMLs are wrong way around, automatically swap them.
  35 --      - Check that one of the NHMLs is sound and other is video.
  36 --
  37 ----------------------------------------------------------------------------------------------------------------------
  38 ----------------------------------------------------------------------------------------------------------------------
  39
  40 --Lua 5.2 fix:
  41 unpack = unpack or table.unpack;
  42
  43 ----------------------------------------------------------------------------------------------------------------------
  44 -- Function reduce_fraction(number numerator, number denumerator)
  45 -- Returns reduced fraction.
  46 ----------------------------------------------------------------------------------------------------------------------
  47 reduce_fraction = function(numerator, denumerator)
  48         local x, y = numerator, denumerator;
  49         while y > 0 do
  50                 x, y = y, x % y;
  51         end
  52         return numerator / x, denumerator / x;
  53 end
  54
  55 ----------------------------------------------------------------------------------------------------------------------
  56 -- Function load_timecode_file(FILE file, number timescale)
  57 -- Loads timecode data from file @file, using timescale of @timescale frames per second. Returns array of scaled
  58 -- timecodes.
  59 ----------------------------------------------------------------------------------------------------------------------
  60 load_timecode_file = function(file, timescale)
  61         local line, ret;
  62         line = file:read("*l");
  63         if line ~= "# timecode format v2" then
  64                 error("Timecode file is not in MKV timecodes v2 format");
  65         end
  66         ret = {};
  67         while true do
  68                 line = file:read("*l");
  69                 if not line then
  70                         break;
  71                 end
  72                 local timecode = tonumber(line);
  73                 if not timecode then
  74                         error("Can't parse timecode '" .. line .. "'.");
  75                 end
  76                 table.insert(ret, math.floor(0.5 + timecode / 1000 * timescale));
  77         end
  78         return ret;
  79 end
  80
  81 ----------------------------------------------------------------------------------------------------------------------
  82 -- Function make_reverse_index_table(Array array)
  83 -- Returns table, that has entry for each entry in given array @array with value being rank of value, 1 being smallest
  84 -- and #array the largest. If @lookup is non-nil, values are looked up from that array.
  85 ----------------------------------------------------------------------------------------------------------------------
  86 make_reverse_index_table = function(array, lookup)
  87         local sorted, ret;
  88         local i;
  89         sorted = {};
  90         for i = 1,#array do
  91                 sorted[i] = array[i];
  92         end
  93         table.sort(sorted);
  94         ret = {};
  95         for i = 1,#sorted do
  96                 ret[sorted[i]] = (lookup and lookup[i]) or i;
  97         end
  98         return ret;
  99 end
 100
 101 ----------------------------------------------------------------------------------------------------------------------
 102 -- Function max_causality_violaton(Array CTS, Array DTS)
 103 -- Return the maximum number of time units CTS and DTS values violate causality. #CTS must equal #DTS.
 104 ----------------------------------------------------------------------------------------------------------------------
 105 max_causality_violation = function(CTS, DTS)
 106         local max_cv = 0;
 107         local i;
 108         for i = 1,#CTS do
 109                 max_cv = math.max(max_cv, DTS[i] - CTS[i]);
 110         end
 111         return max_cv;
 112 end
 113
 114 ----------------------------------------------------------------------------------------------------------------------
 115 -- Function fixup_video_times(Array sampledata, Array timecodes, Number spec_delay)
 116 -- Fixes video timing of @sampledata (fields CTS and DTS) to be consistent with timecodes in @timecodes. Returns the
 117 -- CTS offset of first sample (for fixing audio). @spec_delay is special delay to add (to fix A/V sync).
 118 ----------------------------------------------------------------------------------------------------------------------
 119 fixup_video_times = function(sampledata, timecodes, spec_delay)
 120         local cts_tab = {};
 121         local dts_tab = {};
 122         local k, v, i;
 123
 124         if not timecodes then
 125                 local min_cts = 999999999999999999999;
 126                 for i = 1,#sampledata do
 127                         --Maximum causality violation is always zero in valid HHML.
 128                         sampledata[i].CTS = sampledata[i].CTS + spec_delay;
 129                         --Spec_delay should not apply to audio.
 130                         min_cts = math.min(min_cts, sampledata[i].CTS - spec_delay);
 131                 end
 132                 return min_cts;
 133         end
 134
 135         if #sampledata ~= #timecodes then
 136                 error("Number of samples (" .. #sampledata .. ") does not match number of timecodes (" .. #timecodes
 137                         .. ").");
 138         end
 139         for i = 1,#sampledata do
 140                 cts_tab[i] = sampledata[i].CTS;
 141                 dts_tab[i] = sampledata[i].DTS;
 142         end
 143         cts_lookup = make_reverse_index_table(cts_tab, timecodes);
 144         dts_lookup = make_reverse_index_table(dts_tab, timecodes);
 145
 146         -- Perform time translation and find max causality violation.
 147         local max_cv = 0;
 148         for i = 1,#sampledata do
 149                 sampledata[i].CTS = cts_lookup[sampledata[i].CTS];
 150                 sampledata[i].DTS = dts_lookup[sampledata[i].DTS];
 151                 max_cv = math.max(max_cv, sampledata[i].DTS - sampledata[i].CTS);
 152         end
 153         -- Add maximum causality violation to CTS to eliminate the causality violations.
 154         -- Also find the minimum CTS.
 155         local min_cts = 999999999999999999999;
 156         for i = 1,#sampledata do
 157                 sampledata[i].CTS = sampledata[i].CTS + max_cv + spec_delay;
 158                 --Spec_delay should not apply to audio.
 159                 min_cts = math.min(min_cts, sampledata[i].CTS - spec_delay);
 160         end
 161         return min_cts;
 162 end
 163
 164 ----------------------------------------------------------------------------------------------------------------------
 165 -- Function fixup_video_times(Array sampledata, Number min_video_cts, Number video_timescale, Number audio_timescale)
 166 -- Fixes video timing of @sampledata (field CTS) to be consistent with video minimum CTS of @cts. Video timescale
 167 -- is assumed to be @video_timescale and audio timescale @audio_timescale.
 168 ----------------------------------------------------------------------------------------------------------------------
 169 fixup_audio_times = function(sampledata, min_video_cts, video_timescale, audio_timescale)
 170         local fixup = math.floor(0.5 + min_video_cts * audio_timescale / video_timescale);
 171         for i = 1,#sampledata do
 172                 sampledata[i].CTS = sampledata[i].CTS + fixup;
 173         end
 174 end
 175
 176 ----------------------------------------------------------------------------------------------------------------------
 177 -- Function translate_NHML_TS_in(Array sampledata);
 178 -- Translate NHML CTSOffset fields in @sampledata into CTS fields.
 179 ----------------------------------------------------------------------------------------------------------------------
 180 translate_NHML_TS_in = function(sampledata, default_dDTS)
 181         local i;
 182         local dts = 0;
 183         for i = 1,#sampledata do
 184                 if not sampledata[i].DTS then
 185                         sampledata[i].DTS = dts + default_dDTS;
 186                 end
 187                 dts = sampledata[i].DTS;
 188                 if sampledata[i].CTSOffset then
 189                         sampledata[i].CTS = sampledata[i].CTSOffset + sampledata[i].DTS;
 190                 else
 191                         sampledata[i].CTS = sampledata[i].DTS;
 192                 end
 193         end
 194 end
 195
 196 ----------------------------------------------------------------------------------------------------------------------
 197 -- Function translate_NHML_TS_out(Array sampledata);
 198 -- Translate CTS fields in @sampledata into NHML CTSOffset fields.
 199 ----------------------------------------------------------------------------------------------------------------------
 200 translate_NHML_TS_out = function(sampledata)
 201         local i;
 202         for i = 1,#sampledata do
 203                 sampledata[i].CTSOffset = sampledata[i].CTS - sampledata[i].DTS;
 204                 if sampledata[i].CTSOffset < 0 then
 205                         error("INTERNAL ERROR: translate_NHML_TS_out: Causality violation: CTS=" .. tostring(
 206                                 sampledata[i].CTS) .. " DTS=" .. tostring(sampledata[i].DTS) .. ".");
 207                 end
 208                 sampledata[i].CTS = nil;
 209         end
 210 end
 211
 212 ----------------------------------------------------------------------------------------------------------------------
 213 -- Function map_table_to_number(Table tab);
 214 -- Translate all numeric fields in table @tab into numbers.
 215 ----------------------------------------------------------------------------------------------------------------------
 216 map_table_to_number = function(tab)
 217         local k, v;
 218         for k, v in pairs(tab) do
 219                 local n = tonumber(v);
 220                 if n then
 221                         tab[k] = n;
 222                 end
 223         end
 224 end
 225
 226 ----------------------------------------------------------------------------------------------------------------------
 227 -- Function map_fields_to_number(Array sampledata);
 228 -- Translate all numeric fields in array @sampledata into numbers.
 229 ----------------------------------------------------------------------------------------------------------------------
 230 map_fields_to_number = function(sampledata)
 231         local i;
 232         for i = 1,#sampledata do
 233                 map_table_to_number(sampledata[i]);
 234         end
 235 end
 236
 237 ----------------------------------------------------------------------------------------------------------------------
 238 -- Function escape_xml_text(String str)
 239 -- Return XML escaping of text str.
 240 ----------------------------------------------------------------------------------------------------------------------
 241 escape_xml_text = function(str)
 242         str = string.gsub(str, "&", "&amp;");
 243         str = string.gsub(str, "<", "&lt;");
 244         str = string.gsub(str, ">", "&gt;");
 245         str = string.gsub(str, "\"", "&quot;");
 246         str = string.gsub(str, "\'", "&apos;");
 247         return str;
 248 end
 249
 250 ----------------------------------------------------------------------------------------------------------------------
 251 -- Function escape_xml_text(String str)
 252 -- Return XML unescaping of text str.
 253 ----------------------------------------------------------------------------------------------------------------------
 254 unescape_xml_text = function(str)
 255         str = string.gsub(str, "&apos;", "\'");
 256         str = string.gsub(str, "&quot;", "\"");
 257         str = string.gsub(str, "&gt;", ">");
 258         str = string.gsub(str, "&lt;", "<");
 259         str = string.gsub(str, "&amp;", "&");
 260         return str;
 261 end
 262
 263 ----------------------------------------------------------------------------------------------------------------------
 264 -- Function serialize_table_to_xml_entity(File file, String tag, Table data, bool noclose);
 265 -- Write @data as XML start tag of type @tag into @file. If noclose is true, then tag will not be closed.
 266 ----------------------------------------------------------------------------------------------------------------------
 267 serialize_table_to_xml_entity = function(file, tag, data, noclose)
 268         local k, v;
 269         file:write("<" .. tag .. " ");
 270         for k, v in pairs(data) do
 271                 file:write(k .. "=\"" .. escape_xml_text(tostring(v)) .. "\" ");
 272         end
 273         if noclose then
 274                 file:write(">\n");
 275         else
 276                 file:write("/>\n");
 277         end
 278 end
 279
 280 ----------------------------------------------------------------------------------------------------------------------
 281 -- Function serialize_array_to_xml_entity(File file, String tag, Array data);
 282 -- Write each element of @data as empty XML tag of type @tag into @file.
 283 ----------------------------------------------------------------------------------------------------------------------
 284 serialize_array_to_xml_entity = function(file, tag, data)
 285         local i;
 286         for i = 1,#data do
 287                 serialize_table_to_xml_entity(file, tag, data[i]);
 288         end
 289 end
 290
 291 ----------------------------------------------------------------------------------------------------------------------
 292 -- Function write_NHML_data(File file, Table header, Table sampledata)
 293 -- Write entiere NHML file.
 294 ----------------------------------------------------------------------------------------------------------------------
 295 write_NHML_data = function(file, header, sampledata)
 296         file:write("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n");
 297         serialize_table_to_xml_entity(file, "NHNTStream", header, true);
 298         serialize_array_to_xml_entity(file, "NHNTSample", sampledata);
 299         file:write("</NHNTStream>\n");
 300 end
 301
 302 ----------------------------------------------------------------------------------------------------------------------
 303 -- Function open_file_checked(String file, String mode, bool for_write)
 304 -- Return file handle to file (checking that open succeeds).
 305 ----------------------------------------------------------------------------------------------------------------------
 306 open_file_checked = function(file, mode, for_write)
 307         local a, b;
 308         a, b = io.open(file, mode);
 309         if not a then
 310                 error("Can't open '" .. file .. "': " .. b);
 311         end
 312         return a;
 313 end
 314
 315 ----------------------------------------------------------------------------------------------------------------------
 316 -- Function call_with_file(fun, string file, String mode, ...);
 317 -- Call fun with opened file handle to @file (in mode @mode) as first parameter.
 318 ----------------------------------------------------------------------------------------------------------------------
 319 call_with_file = function(fun, file, mode, ...)
 320         -- FIXME: Handle nils returned from function.
 321         local handle = open_file_checked(file, mode);
 322         local ret = {fun(handle, ...)};
 323         handle:close();
 324         return unpack(ret);
 325 end
 326
 327 ----------------------------------------------------------------------------------------------------------------------
 328 -- Function xml_parse_tag(String line);
 329 -- Returns the xml tag type for @line plus table of attributes.
 330 ----------------------------------------------------------------------------------------------------------------------
 331 xml_parse_tag = function(line)
 332         -- More regexping...
 333         local tagname;
 334         local attr = {};
 335         tagname = string.match(line, "<(%S+).*>");
 336         if not tagname then
 337                 error("'" .. line .. "': Parse error.");
 338         end
 339         local k, v;
 340         for k, v in string.gmatch(line, "([^ =]+)=\"([^\"]*)\"") do
 341                 attr[k] = unescape_xml_text(v);
 342         end
 343         return tagname, attr;
 344 end
 345
 346 ----------------------------------------------------------------------------------------------------------------------
 347 -- Function load_NHML(File file)
 348 -- Loads NHML file @file. Returns header table and samples array.
 349 ----------------------------------------------------------------------------------------------------------------------
 350 load_NHML = function(file)
 351         -- Let's regexp this shit...
 352         local header = {};
 353         local samples = {};
 354         while true do
 355                 local line = file:read();
 356                 if not line then
 357                         error("Unexpected end of NHML file.");
 358                 end
 359                 local xtag, attributes;
 360                 xtag, attributes = xml_parse_tag(line);
 361                 if xtag == "NHNTStream" then
 362                         header = attributes;
 363                 elseif xtag == "NHNTSample" then
 364                         table.insert(samples, attributes);
 365                 elseif xtag == "/NHNTStream" then
 366                         break;
 367                 elseif xtag == "?xml" then
 368                 else
 369                         print("WARNING: Unrecognized tag '" .. xtag .. "'.");
 370                 end
 371         end
 372         return header, samples;
 373 end
 374
 375 ----------------------------------------------------------------------------------------------------------------------
 376 -- Function reame_errcheck(String old, String new)
 377 -- Rename old to new. With error checking.
 378 ----------------------------------------------------------------------------------------------------------------------
 379 rename_errcheck = function(old, new, backup)
 380         local a, b;
 381         os.remove(backup);
 382         a, b = os.rename(new, backup);
 383         if not a then
 384                 error("Can't rename '" .. new .. "' -> '" .. backup .. "': " .. b);
 385         end
 386         a, b = os.rename(old, new);
 387         if not a then
 388                 error("Can't rename '" .. old .. "' -> '" .. new .. "': " .. b);
 389         end
 390 end
 391
 392 ----------------------------------------------------------------------------------------------------------------------
 393 -- Function compute_max_div(Integer ctsBound, Integer timescale, Integer maxCode, pictureOffset)
 394 -- Compute maximum allowable timescale.
 395 ----------------------------------------------------------------------------------------------------------------------
 396 compute_max_div = function(ctsBound, timeScale, maxCode, pictureOffset)
 397         -- Compute the logical number of frames.
 398         local logicalFrames = ctsBound / pictureOffset;
 399         local maxNumerator = math.floor(maxCode / logicalFrames);
 400         -- Be conservative and assume numerator is rounded up. That is, solve the biggest maxdiv such that for all
 401         -- 1 <= x <= maxdiv, maxNumerator >= ceil(x * pictureOffset / timeScale) is true.
 402         -- Since maxNumerator is integer, this is equivalent to:
 403         -- maxNumerator >= x * pictureOffset / timeScale
 404         -- => maxNumerator * timeScale / pictureOffset >= x, thus
 405         -- maxDiv = math.floor(maxNumerator * timeScale / pictureOffset);
 406         return math.floor(maxNumerator * timeScale / pictureOffset);
 407 end
 408
 409 ----------------------------------------------------------------------------------------------------------------------
 410 -- Function rational_approximate(Integer origNum, Integer origDenum, Integer maxDenum)
 411 -- Approximate origNum / origDenum using rational with maximum denumerator of maxDenum
 412 ----------------------------------------------------------------------------------------------------------------------
 413 rational_approximate = function(origNum, origDenum, maxDenum)
 414         -- FIXME: Better approximations are possible.
 415         local div = math.ceil(origDenum / maxDenum);
 416         return math.floor(0.5 + origNum / div), math.floor(0.5 + origDenum / div);
 417 end
 418
 419 ----------------------------------------------------------------------------------------------------------------------
 420 -- Function fixup_mp4box_bug_cfr(Table header, Table samples, Integer pictureOffset, Integer maxdiv)
 421 -- Fix MP4Box timecode bug for CFR video by approximating the framerate a bit.
 422 ----------------------------------------------------------------------------------------------------------------------
 423 fixup_mp4box_bug_cfr = function(header, samples, pictureOffset, maxdiv)
 424         local oNum, oDenum;
 425         local nNum, nDenum;
 426         local i;
 427         oNum, oDenum = pictureOffset, header.timeScale;
 428         nNum, nDenum = rational_approximate(oNum, oDenum, maxdiv);
 429         header.timeScale = nDenum;
 430         for i = 1, #samples do
 431                 samples[i].DTS = math.floor(0.5 + samples[i].DTS / oNum * nNum);
 432                 samples[i].CTS = math.floor(0.5 + samples[i].CTS / oNum * nNum);
 433         end
 434 end
 435
 436
 437 if #arg < 3 then
 438         error("Syntax: NHMLFixup.lua <video.nhml> <audio.nhml> <timecodes.txt> [delay=<delay>] [tvaspect|widescreen]");
 439 end
 440
 441 -- Load the NHML files.
 442 io.stdout:write("Loading '" .. arg[1] .. "'..."); io.stdout:flush();
 443 video_header, video_samples = call_with_file(load_NHML, arg[1], "r");
 444 io.stdout:write("Done.\n");
 445 io.stdout:write("Loading '" .. arg[2] .. "'..."); io.stdout:flush();
 446 audio_header, audio_samples = call_with_file(load_NHML, arg[2], "r");
 447 io.stdout:write("Done.\n");
 448 io.stdout:write("String to number conversion on video header..."); io.stdout:flush();
 449 map_table_to_number(video_header);
 450 io.stdout:write("Done.\n");
 451 io.stdout:write("String to number conversion on video samples..."); io.stdout:flush();
 452 map_fields_to_number(video_samples);
 453 io.stdout:write("Done.\n");
 454 io.stdout:write("String to number conversion on audio header..."); io.stdout:flush();
 455 map_table_to_number(audio_header);
 456 io.stdout:write("Done.\n");
 457 io.stdout:write("String to number conversion on audio samples..."); io.stdout:flush();
 458 map_fields_to_number(audio_samples);
 459 io.stdout:write("Done.\n");
 460 if video_header.streamType == 4 and audio_header.streamType == 5 then
 461         -- Ok.
 462 elseif video_header.streamType == 5 and audio_header.streamType == 4 then
 463         print("WARNING: You got audio and video wrong way around. Swapping them for you...");
 464         audio_header,audio_samples,arg[2],video_header,video_samples,arg[1] =
 465                 video_header,video_samples,arg[1],audio_header,audio_samples,arg[2];
 466 else
 467         error("Expected one video track and one audio track");
 468 end
 469
 470 if video_header.trackID == audio_header.trackID then
 471         print("WARNING: Audio and video have the same track id. Assigning new track id to audio track...");
 472         audio_header.trackID = audio_header.trackID + 1;
 473 end
 474
 475 io.stdout:write("Computing CTS for video samples..."); io.stdout:flush();
 476 translate_NHML_TS_in(video_samples, video_header.DTS_increment or 0);
 477 io.stdout:write("Done.\n");
 478 io.stdout:write("Computing CTS for audio samples..."); io.stdout:flush();
 479 translate_NHML_TS_in(audio_samples, audio_header.DTS_increment or 0);
 480 io.stdout:write("Done.\n");
 481
 482 -- Alter timescale if needed and load the timecode data.
 483 delay = 0;
 484 rdelay = 0;
 485 for i = 4,#arg do
 486         if arg[i] == "tvaspect" then
 487                 do_aspect_fixup = 1;
 488         elseif arg[i] == "widescreen" then
 489                 do_aspect_fixup = 2;
 490         elseif string.sub(arg[i], 1, 6) == "delay=" then
 491                 local n = tonumber(string.sub(arg[i], 7, #(arg[i])));
 492                 if not n then
 493                         error("Bad delay.");
 494                 end
 495                 rdelay = n;
 496                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 497         end
 498 end
 499
 500
 501 MAX_MP4BOX_TIMECODE = 0x7FFFFFF;
 502 if arg[3] ~= "@CFR" then
 503         timecode_data = call_with_file(load_timecode_file, arg[3], "r", video_header.timeScale);
 504         if timecode_data[#timecode_data] > MAX_MP4BOX_TIMECODE then
 505                 -- Workaround MP4Box bug.
 506                 divider = math.ceil(timecode_data[#timecode_data] / MAX_MP4BOX_TIMECODE);
 507                 print("Notice: Dividing timecodes by " .. divider .. " to workaround MP4Box timecode bug.");
 508                 io.stdout:write("Performing division..."); io.stdout:flush();
 509                 video_header.timeScale = math.floor(0.5 + video_header.timeScale / divider);
 510                 for i = 1,#timecode_data do
 511                         timecode_data[i] = math.floor(0.5 + timecode_data[i] / divider);
 512                 end
 513                 --Recompute delay.
 514                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 515                 io.stdout:write("Done.\n");
 516         end
 517 else
 518         timecode_data = nil;
 519         local maxCTS = 0;
 520         local i;
 521         local DTSOffset = (video_samples[2] or video_samples[1]).DTS - video_samples[1].DTS;
 522         if DTSOffset == 0 then
 523                 DTSOffset = 1;
 524         end
 525         for i = 1,#video_samples do
 526                 if video_samples[i].CTS > maxCTS then
 527                         maxCTS = video_samples[i].CTS;
 528                 end
 529                 if video_samples[i].DTS % DTSOffset ~= 0 then
 530                         error("Video is not CFR");
 531                 end
 532                 if (video_samples[i].CTS - video_samples[1].CTS) % DTSOffset ~= 0 then
 533                         error("Video is not CFR");
 534                 end
 535         end
 536         if video_samples[#video_samples].CTS > MAX_MP4BOX_TIMECODE then
 537                 --Workaround MP4Box bug.
 538                 local maxdiv = compute_max_div(maxCTS, video_header.timeScale, MAX_MP4BOX_TIMECODE, DTSOffset);
 539                 print("Notice: Restricting denumerator to " .. maxdiv .. " to workaround MP4Box timecode bug.");
 540                 io.stdout:write("Fixing timecodes..."); io.stdout:flush();
 541                 fixup_mp4box_bug_cfr(video_header, video_samples, DTSOffset, maxdiv);
 542                 --Recompute delay.
 543                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 544                 io.stdout:write("Done.\n");
 545         end
 546 end
 547
 548 -- Do the actual fixup.
 549 io.stdout:write("Fixing up video timecodes..."); io.stdout:flush();
 550 audio_fixup = fixup_video_times(video_samples, timecode_data, delay);
 551 io.stdout:write("Done.\n");
 552 io.stdout:write("Fixing up audio timecodes..."); io.stdout:flush();
 553 fixup_audio_times(audio_samples, audio_fixup, video_header.timeScale, audio_header.timeScale);
 554 io.stdout:write("Done.\n");
 555
 556 if do_aspect_fixup == 1 then
 557         video_header.parNum, video_header.parDen = reduce_fraction(4 * video_header.height, 3 * video_header.width);
 558 end
 559 if do_aspect_fixup == 2 then
 560         video_header.parNum, video_header.parDen = reduce_fraction(16 * video_header.height, 9 * video_header.width);
 561 end
 562
 563 -- Save the NHML files.
 564 io.stdout:write("Computing CTSOffset for video samples..."); io.stdout:flush();
 565 translate_NHML_TS_out(video_samples);
 566 io.stdout:write("Done.\n");
 567 io.stdout:write("Computing CTSOffset for audio samples..."); io.stdout:flush();
 568 translate_NHML_TS_out(audio_samples);
 569 io.stdout:write("Done.\n");
 570 io.stdout:write("Saving '" .. arg[1] .. ".tmp'..."); io.stdout:flush();
 571 call_with_file(write_NHML_data, arg[1] .. ".tmp", "w", video_header, video_samples);
 572 io.stdout:write("Done.\n");
 573 io.stdout:write("Saving '" .. arg[2] .. ".tmp'..."); io.stdout:flush();
 574 call_with_file(write_NHML_data, arg[2] .. ".tmp", "w", audio_header, audio_samples);
 575 io.stdout:write("Done.\n");
 576 io.stdout:write("Renaming '" .. arg[1] .. ".tmp' -> '" .. arg[1] .. "'..."); io.stdout:flush();
 577 rename_errcheck(arg[1] .. ".tmp", arg[1], arg[1] .. ".bak");
 578 io.stdout:write("Done.\n");
 579 io.stdout:write("Renaming '" .. arg[2] .. ".tmp' -> '" .. arg[2] .. "'..."); io.stdout:flush();
 580 rename_errcheck(arg[2] .. ".tmp", arg[2], arg[2] .. ".bak");
 581 io.stdout:write("Done.\n");
 582 io.stdout:write("All done.\n");