scripts/NHMLFixup.lua

   1 #!/usr/bin/env lua
   2 ----------------------------------------------------------------------------------------------------------------------
   3 ----------------------------------------------------------------------------------------------------------------------
   4 -- NHMLFixup v10 by Ilari (2011-08-16).
   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 v10 by Ilari (2011-08-16):
  13 --      Work around MP4Box bug resulting in negative CTSOffset.
  14 --
  15 -- Version v9 by Ilari (2011-04-01):
  16 --      - Support widescreen mode ("widescreen").
  17 --
  18 -- Version v8 by Ilari (2010-12-06):
  19 --      - Support Special timecode file "@CFR" that fixes up audio for CFR encode.
  20 --
  21 -- Version v7 by Ilari (2010-10-24):
  22 --      - Fix bug in time division (use integer timestamps, not decimal ones).
  23 --
  24 -- Version v6 by Ilari (2010-10-24):
  25 --      - Make it work on Lua 5.2 (work 4).
  26 --
  27 -- Version v5 by Ilari (2010-09-18):
  28 --      - Move the files first out of way, since rename-over fails on Windows.
  29 --
  30 -- Version v4 by Ilari (2010-09-17):
  31 --      - Change audio track ID if it collides with video track..
  32 --
  33 -- Version v3 by Ilari (2010-09-17):
  34 --      - Support setting aspect ratio correction.
  35 --
  36 -- Version v2 by Ilari (2010-09-16):
  37 --      - If sound and video NHMLs are wrong way around, automatically swap them.
  38 --      - Check that one of the NHMLs is sound and other is video.
  39 --
  40 ----------------------------------------------------------------------------------------------------------------------
  41 ----------------------------------------------------------------------------------------------------------------------
  42
  43 --Lua 5.2 fix:
  44 unpack = unpack or table.unpack;
  45
  46 ----------------------------------------------------------------------------------------------------------------------
  47 -- Function reduce_fraction(number numerator, number denumerator)
  48 -- Returns reduced fraction.
  49 ----------------------------------------------------------------------------------------------------------------------
  50 reduce_fraction = function(numerator, denumerator)
  51         local x, y = numerator, denumerator;
  52         while y > 0 do
  53                 x, y = y, x % y;
  54         end
  55         return numerator / x, denumerator / x;
  56 end
  57
  58 ----------------------------------------------------------------------------------------------------------------------
  59 -- Function load_timecode_file(FILE file, number timescale)
  60 -- Loads timecode data from file @file, using timescale of @timescale frames per second. Returns array of scaled
  61 -- timecodes.
  62 ----------------------------------------------------------------------------------------------------------------------
  63 load_timecode_file = function(file, timescale)
  64         local line, ret;
  65         line = file:read("*l");
  66         if line ~= "# timecode format v2" then
  67                 error("Timecode file is not in MKV timecodes v2 format");
  68         end
  69         ret = {};
  70         while true do
  71                 line = file:read("*l");
  72                 if not line then
  73                         break;
  74                 end
  75                 local timecode = tonumber(line);
  76                 if not timecode then
  77                         error("Can't parse timecode '" .. line .. "'.");
  78                 end
  79                 table.insert(ret, math.floor(0.5 + timecode / 1000 * timescale));
  80         end
  81         return ret;
  82 end
  83
  84 ----------------------------------------------------------------------------------------------------------------------
  85 -- Function make_reverse_index_table(Array array)
  86 -- Returns table, that has entry for each entry in given array @array with value being rank of value, 1 being smallest
  87 -- and #array the largest. If @lookup is non-nil, values are looked up from that array.
  88 ----------------------------------------------------------------------------------------------------------------------
  89 make_reverse_index_table = function(array, lookup)
  90         local sorted, ret;
  91         local i;
  92         sorted = {};
  93         for i = 1,#array do
  94                 sorted[i] = array[i];
  95         end
  96         table.sort(sorted);
  97         ret = {};
  98         for i = 1,#sorted do
  99                 ret[sorted[i]] = (lookup and lookup[i]) or i;
 100         end
 101         return ret;
 102 end
 103
 104 ----------------------------------------------------------------------------------------------------------------------
 105 -- Function max_causality_violaton(Array CTS, Array DTS)
 106 -- Return the maximum number of time units CTS and DTS values violate causality. #CTS must equal #DTS.
 107 ----------------------------------------------------------------------------------------------------------------------
 108 max_causality_violation = function(CTS, DTS)
 109         local max_cv = 0;
 110         local i;
 111         for i = 1,#CTS do
 112                 max_cv = math.max(max_cv, DTS[i] - CTS[i]);
 113         end
 114         return max_cv;
 115 end
 116
 117 ----------------------------------------------------------------------------------------------------------------------
 118 -- Function fixup_video_times(Array sampledata, Array timecodes, Number spec_delay)
 119 -- Fixes video timing of @sampledata (fields CTS and DTS) to be consistent with timecodes in @timecodes. Returns the
 120 -- CTS offset of first sample (for fixing audio). @spec_delay is special delay to add (to fix A/V sync).
 121 ----------------------------------------------------------------------------------------------------------------------
 122 fixup_video_times = function(sampledata, timecodes, spec_delay)
 123         local cts_tab = {};
 124         local dts_tab = {};
 125         local k, v, i;
 126
 127         if not timecodes then
 128                 local min_cts = 999999999999999999999;
 129                 for i = 1,#sampledata do
 130                         --Maximum causality violation is always zero in valid HHML.
 131                         sampledata[i].CTS = sampledata[i].CTS + spec_delay;
 132                         --Spec_delay should not apply to audio.
 133                         min_cts = math.min(min_cts, sampledata[i].CTS - spec_delay);
 134                 end
 135                 return min_cts;
 136         end
 137
 138         if #sampledata ~= #timecodes then
 139                 error("Number of samples (" .. #sampledata .. ") does not match number of timecodes (" .. #timecodes
 140                         .. ").");
 141         end
 142         for i = 1,#sampledata do
 143                 cts_tab[i] = sampledata[i].CTS;
 144                 dts_tab[i] = sampledata[i].DTS;
 145         end
 146         cts_lookup = make_reverse_index_table(cts_tab, timecodes);
 147         dts_lookup = make_reverse_index_table(dts_tab, timecodes);
 148
 149         -- Perform time translation and find max causality violation.
 150         local max_cv = 0;
 151         for i = 1,#sampledata do
 152                 sampledata[i].CTS = cts_lookup[sampledata[i].CTS];
 153                 sampledata[i].DTS = dts_lookup[sampledata[i].DTS];
 154                 max_cv = math.max(max_cv, sampledata[i].DTS - sampledata[i].CTS);
 155         end
 156         -- Add maximum causality violation to CTS to eliminate the causality violations.
 157         -- Also find the minimum CTS.
 158         local min_cts = 999999999999999999999;
 159         for i = 1,#sampledata do
 160                 sampledata[i].CTS = sampledata[i].CTS + max_cv + spec_delay;
 161                 --Spec_delay should not apply to audio.
 162                 min_cts = math.min(min_cts, sampledata[i].CTS - spec_delay);
 163         end
 164         return min_cts;
 165 end
 166
 167 ----------------------------------------------------------------------------------------------------------------------
 168 -- Function fixup_video_times(Array sampledata, Number min_video_cts, Number video_timescale, Number audio_timescale)
 169 -- Fixes video timing of @sampledata (field CTS) to be consistent with video minimum CTS of @cts. Video timescale
 170 -- is assumed to be @video_timescale and audio timescale @audio_timescale.
 171 ----------------------------------------------------------------------------------------------------------------------
 172 fixup_audio_times = function(sampledata, min_video_cts, video_timescale, audio_timescale)
 173         local fixup = math.floor(0.5 + min_video_cts * audio_timescale / video_timescale);
 174         for i = 1,#sampledata do
 175                 sampledata[i].CTS = sampledata[i].CTS + fixup;
 176         end
 177 end
 178
 179 ----------------------------------------------------------------------------------------------------------------------
 180 -- Function translate_NHML_TS_in(Array sampledata);
 181 -- Translate NHML CTSOffset fields in @sampledata into CTS fields.
 182 ----------------------------------------------------------------------------------------------------------------------
 183 translate_NHML_TS_in = function(sampledata, default_dDTS)
 184         local i;
 185         local dts = 0;
 186         for i = 1,#sampledata do
 187                 if not sampledata[i].DTS then
 188                         sampledata[i].DTS = dts + default_dDTS;
 189                 end
 190                 dts = sampledata[i].DTS;
 191                 if sampledata[i].CTSOffset and sampledata[i].CTSOffset < 0 then
 192                         --Work around MP4Box bug.
 193                         print("WARNING: Negative CTSOffset, assuming buggy MP4Box");
 194                         sampledata[i].CTSOffset = sampledata[i].CTSOffset + 4294967296;
 195                 end
 196                 if sampledata[i].CTSOffset then
 197                         sampledata[i].CTS = sampledata[i].CTSOffset + sampledata[i].DTS;
 198                 else
 199                         sampledata[i].CTS = sampledata[i].DTS;
 200                 end
 201         end
 202 end
 203
 204 ----------------------------------------------------------------------------------------------------------------------
 205 -- Function translate_NHML_TS_out(Array sampledata);
 206 -- Translate CTS fields in @sampledata into NHML CTSOffset fields.
 207 ----------------------------------------------------------------------------------------------------------------------
 208 translate_NHML_TS_out = function(sampledata)
 209         local i;
 210         for i = 1,#sampledata do
 211                 sampledata[i].CTSOffset = sampledata[i].CTS - sampledata[i].DTS;
 212                 if sampledata[i].CTSOffset < 0 then
 213                         error("INTERNAL ERROR: translate_NHML_TS_out: Causality violation: CTS=" .. tostring(
 214                                 sampledata[i].CTS) .. " DTS=" .. tostring(sampledata[i].DTS) .. ".");
 215                 end
 216                 sampledata[i].CTS = nil;
 217         end
 218 end
 219
 220 ----------------------------------------------------------------------------------------------------------------------
 221 -- Function map_table_to_number(Table tab);
 222 -- Translate all numeric fields in table @tab into numbers.
 223 ----------------------------------------------------------------------------------------------------------------------
 224 map_table_to_number = function(tab)
 225         local k, v;
 226         for k, v in pairs(tab) do
 227                 local n = tonumber(v);
 228                 if n then
 229                         tab[k] = n;
 230                 end
 231         end
 232 end
 233
 234 ----------------------------------------------------------------------------------------------------------------------
 235 -- Function map_fields_to_number(Array sampledata);
 236 -- Translate all numeric fields in array @sampledata into numbers.
 237 ----------------------------------------------------------------------------------------------------------------------
 238 map_fields_to_number = function(sampledata)
 239         local i;
 240         for i = 1,#sampledata do
 241                 map_table_to_number(sampledata[i]);
 242         end
 243 end
 244
 245 ----------------------------------------------------------------------------------------------------------------------
 246 -- Function escape_xml_text(String str)
 247 -- Return XML escaping of text str.
 248 ----------------------------------------------------------------------------------------------------------------------
 249 escape_xml_text = function(str)
 250         str = string.gsub(str, "&", "&amp;");
 251         str = string.gsub(str, "<", "&lt;");
 252         str = string.gsub(str, ">", "&gt;");
 253         str = string.gsub(str, "\"", "&quot;");
 254         str = string.gsub(str, "\'", "&apos;");
 255         return str;
 256 end
 257
 258 ----------------------------------------------------------------------------------------------------------------------
 259 -- Function escape_xml_text(String str)
 260 -- Return XML unescaping of text str.
 261 ----------------------------------------------------------------------------------------------------------------------
 262 unescape_xml_text = function(str)
 263         str = string.gsub(str, "&apos;", "\'");
 264         str = string.gsub(str, "&quot;", "\"");
 265         str = string.gsub(str, "&gt;", ">");
 266         str = string.gsub(str, "&lt;", "<");
 267         str = string.gsub(str, "&amp;", "&");
 268         return str;
 269 end
 270
 271 ----------------------------------------------------------------------------------------------------------------------
 272 -- Function serialize_table_to_xml_entity(File file, String tag, Table data, bool noclose);
 273 -- Write @data as XML start tag of type @tag into @file. If noclose is true, then tag will not be closed.
 274 ----------------------------------------------------------------------------------------------------------------------
 275 serialize_table_to_xml_entity = function(file, tag, data, noclose)
 276         local k, v;
 277         file:write("<" .. tag .. " ");
 278         for k, v in pairs(data) do
 279                 file:write(k .. "=\"" .. escape_xml_text(tostring(v)) .. "\" ");
 280         end
 281         if noclose then
 282                 file:write(">\n");
 283         else
 284                 file:write("/>\n");
 285         end
 286 end
 287
 288 ----------------------------------------------------------------------------------------------------------------------
 289 -- Function serialize_array_to_xml_entity(File file, String tag, Array data);
 290 -- Write each element of @data as empty XML tag of type @tag into @file.
 291 ----------------------------------------------------------------------------------------------------------------------
 292 serialize_array_to_xml_entity = function(file, tag, data)
 293         local i;
 294         for i = 1,#data do
 295                 serialize_table_to_xml_entity(file, tag, data[i]);
 296         end
 297 end
 298
 299 ----------------------------------------------------------------------------------------------------------------------
 300 -- Function write_NHML_data(File file, Table header, Table sampledata)
 301 -- Write entiere NHML file.
 302 ----------------------------------------------------------------------------------------------------------------------
 303 write_NHML_data = function(file, header, sampledata)
 304         file:write("<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"no\"?>\n");
 305         serialize_table_to_xml_entity(file, "NHNTStream", header, true);
 306         serialize_array_to_xml_entity(file, "NHNTSample", sampledata);
 307         file:write("</NHNTStream>\n");
 308 end
 309
 310 ----------------------------------------------------------------------------------------------------------------------
 311 -- Function open_file_checked(String file, String mode, bool for_write)
 312 -- Return file handle to file (checking that open succeeds).
 313 ----------------------------------------------------------------------------------------------------------------------
 314 open_file_checked = function(file, mode, for_write)
 315         local a, b;
 316         a, b = io.open(file, mode);
 317         if not a then
 318                 error("Can't open '" .. file .. "': " .. b);
 319         end
 320         return a;
 321 end
 322
 323 ----------------------------------------------------------------------------------------------------------------------
 324 -- Function call_with_file(fun, string file, String mode, ...);
 325 -- Call fun with opened file handle to @file (in mode @mode) as first parameter.
 326 ----------------------------------------------------------------------------------------------------------------------
 327 call_with_file = function(fun, file, mode, ...)
 328         -- FIXME: Handle nils returned from function.
 329         local handle = open_file_checked(file, mode);
 330         local ret = {fun(handle, ...)};
 331         handle:close();
 332         return unpack(ret);
 333 end
 334
 335 ----------------------------------------------------------------------------------------------------------------------
 336 -- Function xml_parse_tag(String line);
 337 -- Returns the xml tag type for @line plus table of attributes.
 338 ----------------------------------------------------------------------------------------------------------------------
 339 xml_parse_tag = function(line)
 340         -- More regexping...
 341         local tagname;
 342         local attr = {};
 343         tagname = string.match(line, "<(%S+).*>");
 344         if not tagname then
 345                 error("'" .. line .. "': Parse error.");
 346         end
 347         local k, v;
 348         for k, v in string.gmatch(line, "([^ =]+)=\"([^\"]*)\"") do
 349                 attr[k] = unescape_xml_text(v);
 350         end
 351         return tagname, attr;
 352 end
 353
 354 ----------------------------------------------------------------------------------------------------------------------
 355 -- Function load_NHML(File file)
 356 -- Loads NHML file @file. Returns header table and samples array.
 357 ----------------------------------------------------------------------------------------------------------------------
 358 load_NHML = function(file)
 359         -- Let's regexp this shit...
 360         local header = {};
 361         local samples = {};
 362         while true do
 363                 local line = file:read();
 364                 if not line then
 365                         error("Unexpected end of NHML file.");
 366                 end
 367                 local xtag, attributes;
 368                 xtag, attributes = xml_parse_tag(line);
 369                 if xtag == "NHNTStream" then
 370                         header = attributes;
 371                 elseif xtag == "NHNTSample" then
 372                         table.insert(samples, attributes);
 373                 elseif xtag == "/NHNTStream" then
 374                         break;
 375                 elseif xtag == "?xml" then
 376                 else
 377                         print("WARNING: Unrecognized tag '" .. xtag .. "'.");
 378                 end
 379         end
 380         return header, samples;
 381 end
 382
 383 ----------------------------------------------------------------------------------------------------------------------
 384 -- Function reame_errcheck(String old, String new)
 385 -- Rename old to new. With error checking.
 386 ----------------------------------------------------------------------------------------------------------------------
 387 rename_errcheck = function(old, new, backup)
 388         local a, b;
 389         os.remove(backup);
 390         a, b = os.rename(new, backup);
 391         if not a then
 392                 error("Can't rename '" .. new .. "' -> '" .. backup .. "': " .. b);
 393         end
 394         a, b = os.rename(old, new);
 395         if not a then
 396                 error("Can't rename '" .. old .. "' -> '" .. new .. "': " .. b);
 397         end
 398 end
 399
 400 ----------------------------------------------------------------------------------------------------------------------
 401 -- Function compute_max_div(Integer ctsBound, Integer timescale, Integer maxCode, pictureOffset)
 402 -- Compute maximum allowable timescale.
 403 ----------------------------------------------------------------------------------------------------------------------
 404 compute_max_div = function(ctsBound, timeScale, maxCode, pictureOffset)
 405         -- Compute the logical number of frames.
 406         local logicalFrames = ctsBound / pictureOffset;
 407         local maxNumerator = math.floor(maxCode / logicalFrames);
 408         -- Be conservative and assume numerator is rounded up. That is, solve the biggest maxdiv such that for all
 409         -- 1 <= x <= maxdiv, maxNumerator >= ceil(x * pictureOffset / timeScale) is true.
 410         -- Since maxNumerator is integer, this is equivalent to:
 411         -- maxNumerator >= x * pictureOffset / timeScale
 412         -- => maxNumerator * timeScale / pictureOffset >= x, thus
 413         -- maxDiv = math.floor(maxNumerator * timeScale / pictureOffset);
 414         return math.floor(maxNumerator * timeScale / pictureOffset);
 415 end
 416
 417 ----------------------------------------------------------------------------------------------------------------------
 418 -- Function rational_approximate(Integer origNum, Integer origDenum, Integer maxDenum)
 419 -- Approximate origNum / origDenum using rational with maximum denumerator of maxDenum
 420 ----------------------------------------------------------------------------------------------------------------------
 421 rational_approximate = function(origNum, origDenum, maxDenum)
 422         -- FIXME: Better approximations are possible.
 423         local div = math.ceil(origDenum / maxDenum);
 424         return math.floor(0.5 + origNum / div), math.floor(0.5 + origDenum / div);
 425 end
 426
 427 ----------------------------------------------------------------------------------------------------------------------
 428 -- Function fixup_mp4box_bug_cfr(Table header, Table samples, Integer pictureOffset, Integer maxdiv)
 429 -- Fix MP4Box timecode bug for CFR video by approximating the framerate a bit.
 430 ----------------------------------------------------------------------------------------------------------------------
 431 fixup_mp4box_bug_cfr = function(header, samples, pictureOffset, maxdiv)
 432         local oNum, oDenum;
 433         local nNum, nDenum;
 434         local i;
 435         oNum, oDenum = pictureOffset, header.timeScale;
 436         nNum, nDenum = rational_approximate(oNum, oDenum, maxdiv);
 437         header.timeScale = nDenum;
 438         for i = 1, #samples do
 439                 samples[i].DTS = math.floor(0.5 + samples[i].DTS / oNum * nNum);
 440                 samples[i].CTS = math.floor(0.5 + samples[i].CTS / oNum * nNum);
 441         end
 442 end
 443
 444
 445 if #arg < 3 then
 446         error("Syntax: NHMLFixup.lua <video.nhml> <audio.nhml> <timecodes.txt> [delay=<delay>] [tvaspect|widescreen]");
 447 end
 448
 449 -- Load the NHML files.
 450 io.stdout:write("Loading '" .. arg[1] .. "'..."); io.stdout:flush();
 451 video_header, video_samples = call_with_file(load_NHML, arg[1], "r");
 452 io.stdout:write("Done.\n");
 453 io.stdout:write("Loading '" .. arg[2] .. "'..."); io.stdout:flush();
 454 audio_header, audio_samples = call_with_file(load_NHML, arg[2], "r");
 455 io.stdout:write("Done.\n");
 456 io.stdout:write("String to number conversion on video header..."); io.stdout:flush();
 457 map_table_to_number(video_header);
 458 io.stdout:write("Done.\n");
 459 io.stdout:write("String to number conversion on video samples..."); io.stdout:flush();
 460 map_fields_to_number(video_samples);
 461 io.stdout:write("Done.\n");
 462 io.stdout:write("String to number conversion on audio header..."); io.stdout:flush();
 463 map_table_to_number(audio_header);
 464 io.stdout:write("Done.\n");
 465 io.stdout:write("String to number conversion on audio samples..."); io.stdout:flush();
 466 map_fields_to_number(audio_samples);
 467 io.stdout:write("Done.\n");
 468 if video_header.streamType == 4 and audio_header.streamType == 5 then
 469         -- Ok.
 470 elseif video_header.streamType == 5 and audio_header.streamType == 4 then
 471         print("WARNING: You got audio and video wrong way around. Swapping them for you...");
 472         audio_header,audio_samples,arg[2],video_header,video_samples,arg[1] =
 473                 video_header,video_samples,arg[1],audio_header,audio_samples,arg[2];
 474 else
 475         error("Expected one video track and one audio track");
 476 end
 477
 478 if video_header.trackID == audio_header.trackID then
 479         print("WARNING: Audio and video have the same track id. Assigning new track id to audio track...");
 480         audio_header.trackID = audio_header.trackID + 1;
 481 end
 482
 483 io.stdout:write("Computing CTS for video samples..."); io.stdout:flush();
 484 translate_NHML_TS_in(video_samples, video_header.DTS_increment or 0);
 485 io.stdout:write("Done.\n");
 486 io.stdout:write("Computing CTS for audio samples..."); io.stdout:flush();
 487 translate_NHML_TS_in(audio_samples, audio_header.DTS_increment or 0);
 488 io.stdout:write("Done.\n");
 489
 490 -- Alter timescale if needed and load the timecode data.
 491 delay = 0;
 492 rdelay = 0;
 493 for i = 4,#arg do
 494         if arg[i] == "tvaspect" then
 495                 do_aspect_fixup = 1;
 496         elseif arg[i] == "widescreen" then
 497                 do_aspect_fixup = 2;
 498         elseif string.sub(arg[i], 1, 6) == "delay=" then
 499                 local n = tonumber(string.sub(arg[i], 7, #(arg[i])));
 500                 if not n then
 501                         error("Bad delay.");
 502                 end
 503                 rdelay = n;
 504                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 505         end
 506 end
 507
 508
 509 MAX_MP4BOX_TIMECODE = 0x7FFFFFF;
 510 if arg[3] ~= "@CFR" then
 511         timecode_data = call_with_file(load_timecode_file, arg[3], "r", video_header.timeScale);
 512         if timecode_data[#timecode_data] > MAX_MP4BOX_TIMECODE then
 513                 -- Workaround MP4Box bug.
 514                 divider = math.ceil(timecode_data[#timecode_data] / MAX_MP4BOX_TIMECODE);
 515                 print("Notice: Dividing timecodes by " .. divider .. " to workaround MP4Box timecode bug.");
 516                 io.stdout:write("Performing division..."); io.stdout:flush();
 517                 video_header.timeScale = math.floor(0.5 + video_header.timeScale / divider);
 518                 for i = 1,#timecode_data do
 519                         timecode_data[i] = math.floor(0.5 + timecode_data[i] / divider);
 520                 end
 521                 --Recompute delay.
 522                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 523                 io.stdout:write("Done.\n");
 524         end
 525 else
 526         timecode_data = nil;
 527         local maxCTS = 0;
 528         local i;
 529         local DTSOffset = (video_samples[2] or video_samples[1]).DTS - video_samples[1].DTS;
 530         if DTSOffset == 0 then
 531                 DTSOffset = 1;
 532         end
 533         for i = 1,#video_samples do
 534                 if video_samples[i].CTS > maxCTS then
 535                         maxCTS = video_samples[i].CTS;
 536                 end
 537                 if video_samples[i].DTS % DTSOffset ~= 0 then
 538                         error("Video is not CFR");
 539                 end
 540                 if (video_samples[i].CTS - video_samples[1].CTS) % DTSOffset ~= 0 then
 541                         error("Video is not CFR");
 542                 end
 543         end
 544         if video_samples[#video_samples].CTS > MAX_MP4BOX_TIMECODE then
 545                 --Workaround MP4Box bug.
 546                 local maxdiv = compute_max_div(maxCTS, video_header.timeScale, MAX_MP4BOX_TIMECODE, DTSOffset);
 547                 print("Notice: Restricting denumerator to " .. maxdiv .. " to workaround MP4Box timecode bug.");
 548                 io.stdout:write("Fixing timecodes..."); io.stdout:flush();
 549                 fixup_mp4box_bug_cfr(video_header, video_samples, DTSOffset, maxdiv);
 550                 --Recompute delay.
 551                 delay = math.floor(0.5 + rdelay / 1000 * video_header.timeScale);
 552                 io.stdout:write("Done.\n");
 553         end
 554 end
 555
 556 -- Do the actual fixup.
 557 io.stdout:write("Fixing up video timecodes..."); io.stdout:flush();
 558 audio_fixup = fixup_video_times(video_samples, timecode_data, delay);
 559 io.stdout:write("Done.\n");
 560 io.stdout:write("Fixing up audio timecodes..."); io.stdout:flush();
 561 fixup_audio_times(audio_samples, audio_fixup, video_header.timeScale, audio_header.timeScale);
 562 io.stdout:write("Done.\n");
 563
 564 if do_aspect_fixup == 1 then
 565         video_header.parNum, video_header.parDen = reduce_fraction(4 * video_header.height, 3 * video_header.width);
 566 end
 567 if do_aspect_fixup == 2 then
 568         video_header.parNum, video_header.parDen = reduce_fraction(16 * video_header.height, 9 * video_header.width);
 569 end
 570
 571 -- Save the NHML files.
 572 io.stdout:write("Computing CTSOffset for video samples..."); io.stdout:flush();
 573 translate_NHML_TS_out(video_samples);
 574 io.stdout:write("Done.\n");
 575 io.stdout:write("Computing CTSOffset for audio samples..."); io.stdout:flush();
 576 translate_NHML_TS_out(audio_samples);
 577 io.stdout:write("Done.\n");
 578 io.stdout:write("Saving '" .. arg[1] .. ".tmp'..."); io.stdout:flush();
 579 call_with_file(write_NHML_data, arg[1] .. ".tmp", "w", video_header, video_samples);
 580 io.stdout:write("Done.\n");
 581 io.stdout:write("Saving '" .. arg[2] .. ".tmp'..."); io.stdout:flush();
 582 call_with_file(write_NHML_data, arg[2] .. ".tmp", "w", audio_header, audio_samples);
 583 io.stdout:write("Done.\n");
 584 io.stdout:write("Renaming '" .. arg[1] .. ".tmp' -> '" .. arg[1] .. "'..."); io.stdout:flush();
 585 rename_errcheck(arg[1] .. ".tmp", arg[1], arg[1] .. ".bak");
 586 io.stdout:write("Done.\n");
 587 io.stdout:write("Renaming '" .. arg[2] .. ".tmp' -> '" .. arg[2] .. "'..."); io.stdout:flush();
 588 rename_errcheck(arg[2] .. ".tmp", arg[2], arg[2] .. ".bak");
 589 io.stdout:write("Done.\n");
 590 io.stdout:write("All done.\n");