aboutsummaryrefslogtreecommitdiff
path: root/youtube_dl/postprocessor/ffmpeg.py
blob: 39a905380c2634509c9ca2e88558e41caf0dd899 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
from __future__ import unicode_literals

import io
import os
import subprocess
import time
import re


from .common import AudioConversionError, PostProcessor

from ..compat import (
    compat_subprocess_get_DEVNULL,
)
from ..utils import (
    encodeArgument,
    encodeFilename,
    get_exe_version,
    is_outdated_version,
    PostProcessingError,
    prepend_extension,
    shell_quote,
    subtitles_filename,
    dfxp2srt,
    ISO639Utils,
    replace_extension,
)


EXT_TO_OUT_FORMATS = {
    'aac': 'adts',
    'flac': 'flac',
    'm4a': 'ipod',
    'mka': 'matroska',
    'mkv': 'matroska',
    'mpg': 'mpeg',
    'ogv': 'ogg',
    'ts': 'mpegts',
    'wma': 'asf',
    'wmv': 'asf',
}
ACODECS = {
    'mp3': 'libmp3lame',
    'aac': 'aac',
    'flac': 'flac',
    'm4a': 'aac',
    'opus': 'libopus',
    'vorbis': 'libvorbis',
    'wav': None,
}


class FFmpegPostProcessorError(PostProcessingError):
    pass


class FFmpegPostProcessor(PostProcessor):
    def __init__(self, downloader=None):
        PostProcessor.__init__(self, downloader)
        self._determine_executables()

    def check_version(self):
        if not self.available:
            raise FFmpegPostProcessorError('ffmpeg or avconv not found. Please install one.')

        required_version = '10-0' if self.basename == 'avconv' else '1.0'
        if is_outdated_version(
                self._versions[self.basename], required_version):
            warning = 'Your copy of %s is outdated, update %s to version %s or newer if you encounter any errors.' % (
                self.basename, self.basename, required_version)
            if self._downloader:
                self._downloader.report_warning(warning)

    @staticmethod
    def get_versions(downloader=None):
        return FFmpegPostProcessor(downloader)._versions

    def _determine_executables(self):
        programs = ['avprobe', 'avconv', 'ffmpeg', 'ffprobe']
        prefer_ffmpeg = True

        def get_ffmpeg_version(path):
            ver = get_exe_version(path, args=['-version'])
            if ver:
                regexs = [
                    r'(?:\d+:)?([0-9.]+)-[0-9]+ubuntu[0-9.]+$',  # Ubuntu, see [1]
                    r'n([0-9.]+)$',  # Arch Linux
                    # 1. http://www.ducea.com/2006/06/17/ubuntu-package-version-naming-explanation/
                ]
                for regex in regexs:
                    mobj = re.match(regex, ver)
                    if mobj:
                        ver = mobj.group(1)
            return ver

        self.basename = None
        self.probe_basename = None

        self._paths = None
        self._versions = None
        if self._downloader:
            prefer_ffmpeg = self._downloader.params.get('prefer_ffmpeg', True)
            location = self._downloader.params.get('ffmpeg_location')
            if location is not None:
                if not os.path.exists(location):
                    self._downloader.report_warning(
                        'ffmpeg-location %s does not exist! '
                        'Continuing without avconv/ffmpeg.' % (location))
                    self._versions = {}
                    return
                elif not os.path.isdir(location):
                    basename = os.path.splitext(os.path.basename(location))[0]
                    if basename not in programs:
                        self._downloader.report_warning(
                            'Cannot identify executable %s, its basename should be one of %s. '
                            'Continuing without avconv/ffmpeg.' %
                            (location, ', '.join(programs)))
                        self._versions = {}
                        return None
                    location = os.path.dirname(os.path.abspath(location))
                    if basename in ('ffmpeg', 'ffprobe'):
                        prefer_ffmpeg = True

                self._paths = dict(
                    (p, os.path.join(location, p)) for p in programs)
                self._versions = dict(
                    (p, get_ffmpeg_version(self._paths[p])) for p in programs)
        if self._versions is None:
            self._versions = dict(
                (p, get_ffmpeg_version(p)) for p in programs)
            self._paths = dict((p, p) for p in programs)

        if prefer_ffmpeg is False:
            prefs = ('avconv', 'ffmpeg')
        else:
            prefs = ('ffmpeg', 'avconv')
        for p in prefs:
            if self._versions[p]:
                self.basename = p
                break

        if prefer_ffmpeg is False:
            prefs = ('avprobe', 'ffprobe')
        else:
            prefs = ('ffprobe', 'avprobe')
        for p in prefs:
            if self._versions[p]:
                self.probe_basename = p
                break

    @property
    def available(self):
        return self.basename is not None

    @property
    def executable(self):
        return self._paths[self.basename]

    @property
    def probe_available(self):
        return self.probe_basename is not None

    @property
    def probe_executable(self):
        return self._paths[self.probe_basename]

    def get_audio_codec(self, path):
        if not self.probe_available:
            raise PostProcessingError('ffprobe or avprobe not found. Please install one.')
        try:
            cmd = [
                encodeFilename(self.probe_executable, True),
                encodeArgument('-show_streams'),
                encodeFilename(self._ffmpeg_filename_argument(path), True)]
            if self._downloader.params.get('verbose', False):
                self._downloader.to_screen('[debug] %s command line: %s' % (self.basename, shell_quote(cmd)))
            handle = subprocess.Popen(cmd, stderr=compat_subprocess_get_DEVNULL(), stdout=subprocess.PIPE, stdin=subprocess.PIPE)
            output = handle.communicate()[0]
            if handle.wait() != 0:
                return None
        except (IOError, OSError):
            return None
        audio_codec = None
        for line in output.decode('ascii', 'ignore').split('\n'):
            if line.startswith('codec_name='):
                audio_codec = line.split('=')[1].strip()
            elif line.strip() == 'codec_type=audio' and audio_codec is not None:
                return audio_codec
        return None

    def run_ffmpeg_multiple_files(self, input_paths, out_path, opts):
        self.check_version()

        oldest_mtime = min(
            os.stat(encodeFilename(path)).st_mtime for path in input_paths)

        opts += self._configuration_args()

        files_cmd = []
        for path in input_paths:
            files_cmd.extend([
                encodeArgument('-i'),
                encodeFilename(self._ffmpeg_filename_argument(path), True)
            ])
        cmd = ([encodeFilename(self.executable, True), encodeArgument('-y')] +
               files_cmd +
               [encodeArgument(o) for o in opts] +
               [encodeFilename(self._ffmpeg_filename_argument(out_path), True)])

        if self._downloader.params.get('verbose', False):
            self._downloader.to_screen('[debug] ffmpeg command line: %s' % shell_quote(cmd))
        p = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, stdin=subprocess.PIPE)
        stdout, stderr = p.communicate()
        if p.returncode != 0:
            stderr = stderr.decode('utf-8', 'replace')
            msg = stderr.strip().split('\n')[-1]
            raise FFmpegPostProcessorError(msg)
        self.try_utime(out_path, oldest_mtime, oldest_mtime)

    def run_ffmpeg(self, path, out_path, opts):
        self.run_ffmpeg_multiple_files([path], out_path, opts)

    def _ffmpeg_filename_argument(self, fn):
        # Always use 'file:' because the filename may contain ':' (ffmpeg
        # interprets that as a protocol) or can start with '-' (-- is broken in
        # ffmpeg, see https://ffmpeg.org/trac/ffmpeg/ticket/2127 for details)
        # Also leave '-' intact in order not to break streaming to stdout.
        return 'file:' + fn if fn != '-' else fn


class FFmpegExtractAudioPP(FFmpegPostProcessor):
    def __init__(self, downloader=None, preferredcodec=None, preferredquality=None, nopostoverwrites=False):
        FFmpegPostProcessor.__init__(self, downloader)
        if preferredcodec is None:
            preferredcodec = 'best'
        self._preferredcodec = preferredcodec
        self._preferredquality = preferredquality
        self._nopostoverwrites = nopostoverwrites

    def run_ffmpeg(self, path, out_path, codec, more_opts):
        if codec is None:
            acodec_opts = []
        else:
            acodec_opts = ['-acodec', codec]
        opts = ['-vn'] + acodec_opts + more_opts
        try:
            FFmpegPostProcessor.run_ffmpeg(self, path, out_path, opts)
        except FFmpegPostProcessorError as err:
            raise AudioConversionError(err.msg)

    def run(self, information):
        path = information['filepath']

        filecodec = self.get_audio_codec(path)
        if filecodec is None:
            raise PostProcessingError('WARNING: unable to obtain file audio codec with ffprobe')

        more_opts = []
        if self._preferredcodec == 'best' or self._preferredcodec == filecodec or (self._preferredcodec == 'm4a' and filecodec == 'aac'):
            if filecodec == 'aac' and self._preferredcodec in ['m4a', 'best']:
                # Lossless, but in another container
                acodec = 'copy'
                extension = 'm4a'
                more_opts = ['-bsf:a', 'aac_adtstoasc']
            elif filecodec in ['aac', 'flac', 'mp3', 'vorbis', 'opus']:
                # Lossless if possible
                acodec = 'copy'
                extension = filecodec
                if filecodec == 'aac':
                    more_opts = ['-f', 'adts']
                if filecodec == 'vorbis':
                    extension = 'ogg'
            else:
                # MP3 otherwise.
                acodec = 'libmp3lame'
                extension = 'mp3'
                more_opts = []
                if self._preferredquality is not None:
                    if int(self._preferredquality) < 10:
                        more_opts += ['-q:a', self._preferredquality]
                    else:
                        more_opts += ['-b:a', self._preferredquality + 'k']
        else:
            # We convert the audio (lossy if codec is lossy)
            acodec = ACODECS[self._preferredcodec]
            extension = self._preferredcodec
            more_opts = []
            if self._preferredquality is not None:
                # The opus codec doesn't support the -aq option
                if int(self._preferredquality) < 10 and extension != 'opus':
                    more_opts += ['-q:a', self._preferredquality]
                else:
                    more_opts += ['-b:a', self._preferredquality + 'k']
            if self._preferredcodec == 'aac':
                more_opts += ['-f', 'adts']
            if self._preferredcodec == 'm4a':
                more_opts += ['-bsf:a', 'aac_adtstoasc']
            if self._preferredcodec == 'vorbis':
                extension = 'ogg'
            if self._preferredcodec == 'wav':
                extension = 'wav'
                more_opts += ['-f', 'wav']

        prefix, sep, ext = path.rpartition('.')  # not os.path.splitext, since the latter does not work on unicode in all setups
        new_path = prefix + sep + extension

        information['filepath'] = new_path
        information['ext'] = extension

        # If we download foo.mp3 and convert it to... foo.mp3, then don't delete foo.mp3, silly.
        if (new_path == path or
                (self._nopostoverwrites and os.path.exists(encodeFilename(new_path)))):
            self._downloader.to_screen('[ffmpeg] Post-process file %s exists, skipping' % new_path)
            return [], information

        try:
            self._downloader.to_screen('[ffmpeg] Destination: ' + new_path)
            self.run_ffmpeg(path, new_path, acodec, more_opts)
        except AudioConversionError as e:
            raise PostProcessingError(
                'audio conversion failed: ' + e.msg)
        except Exception:
            raise PostProcessingError('error running ' + self.basename)

        # Try to update the date time for extracted audio file.
        if information.get('filetime') is not None:
            self.try_utime(
                new_path, time.time(), information['filetime'],
                errnote='Cannot update utime of audio file')

        return [path], information


class FFmpegVideoConvertorPP(FFmpegPostProcessor):
    def __init__(self, downloader=None, preferedformat=None):
        super(FFmpegVideoConvertorPP, self).__init__(downloader)
        self._preferedformat = preferedformat

    def run(self, information):
        path = information['filepath']
        if information['ext'] == self._preferedformat:
            self._downloader.to_screen('[ffmpeg] Not converting video file %s - already is in target format %s' % (path, self._preferedformat))
            return [], information
        options = []
        if self._preferedformat == 'avi':
            options.extend(['-c:v', 'libxvid', '-vtag', 'XVID'])
        prefix, sep, ext = path.rpartition('.')
        outpath = prefix + sep + self._preferedformat
        self._downloader.to_screen('[' + 'ffmpeg' + '] Converting video from %s to %s, Destination: ' % (information['ext'], self._preferedformat) + outpath)
        self.run_ffmpeg(path, outpath, options)
        information['filepath'] = outpath
        information['format'] = self._preferedformat
        information['ext'] = self._preferedformat
        return [path], information


class FFmpegEmbedSubtitlePP(FFmpegPostProcessor):
    def run(self, information):
        if information['ext'] not in ('mp4', 'webm', 'mkv'):
            self._downloader.to_screen('[ffmpeg] Subtitles can only be embedded in mp4, webm or mkv files')
            return [], information
        subtitles = information.get('requested_subtitles')
        if not subtitles:
            self._downloader.to_screen('[ffmpeg] There aren\'t any subtitles to embed')
            return [], information

        filename = information['filepath']

        ext = information['ext']
        sub_langs = []
        sub_filenames = []
        webm_vtt_warn = False

        for lang, sub_info in subtitles.items():
            sub_ext = sub_info['ext']
            if ext != 'webm' or ext == 'webm' and sub_ext == 'vtt':
                sub_langs.append(lang)
                sub_filenames.append(subtitles_filename(filename, lang, sub_ext))
            else:
                if not webm_vtt_warn and ext == 'webm' and sub_ext != 'vtt':
                    webm_vtt_warn = True
                    self._downloader.to_screen('[ffmpeg] Only WebVTT subtitles can be embedded in webm files')

        if not sub_langs:
            return [], information

        input_files = [filename] + sub_filenames

        opts = [
            '-map', '0',
            '-c', 'copy',
            # Don't copy the existing subtitles, we may be running the
            # postprocessor a second time
            '-map', '-0:s',
        ]
        if information['ext'] == 'mp4':
            opts += ['-c:s', 'mov_text']
        for (i, lang) in enumerate(sub_langs):
            opts.extend(['-map', '%d:0' % (i + 1)])
            lang_code = ISO639Utils.short2long(lang) or lang
            opts.extend(['-metadata:s:s:%d' % i, 'language=%s' % lang_code])

        temp_filename = prepend_extension(filename, 'temp')
        self._downloader.to_screen('[ffmpeg] Embedding subtitles in \'%s\'' % filename)
        self.run_ffmpeg_multiple_files(input_files, temp_filename, opts)
        os.remove(encodeFilename(filename))
        os.rename(encodeFilename(temp_filename), encodeFilename(filename))

        return sub_filenames, information


class FFmpegMetadataPP(FFmpegPostProcessor):
    def run(self, info):
        metadata = {}

        def add(meta_list, info_list=None):
            if not info_list:
                info_list = meta_list
            if not isinstance(meta_list, (list, tuple)):
                meta_list = (meta_list,)
            if not isinstance(info_list, (list, tuple)):
                info_list = (info_list,)
            for info_f in info_list:
                if info.get(info_f) is not None:
                    for meta_f in meta_list:
                        metadata[meta_f] = info[info_f]
                    break

        add('title', ('track', 'title'))
        add('date', 'upload_date')
        add(('description', 'comment'), 'description')
        add('purl', 'webpage_url')
        add('track', 'track_number')
        add('artist', ('artist', 'creator', 'uploader', 'uploader_id'))
        add('genre')
        add('album')
        add('album_artist')
        add('disc', 'disc_number')

        if not metadata:
            self._downloader.to_screen('[ffmpeg] There isn\'t any metadata to add')
            return [], info

        filename = info['filepath']
        temp_filename = prepend_extension(filename, 'temp')
        in_filenames = [filename]
        options = []

        if info['ext'] == 'm4a':
            options.extend(['-vn', '-acodec', 'copy'])
        else:
            options.extend(['-c', 'copy'])

        for (name, value) in metadata.items():
            options.extend(['-metadata', '%s=%s' % (name, value)])

        chapters = info.get('chapters', [])
        if chapters:
            metadata_filename = replace_extension(filename, 'meta')
            with io.open(metadata_filename, 'wt', encoding='utf-8') as f:
                def ffmpeg_escape(text):
                    return re.sub(r'(=|;|#|\\|\n)', r'\\\1', text)

                metadata_file_content = ';FFMETADATA1\n'
                for chapter in chapters:
                    metadata_file_content += '[CHAPTER]\nTIMEBASE=1/1000\n'
                    metadata_file_content += 'START=%d\n' % (chapter['start_time'] * 1000)
                    metadata_file_content += 'END=%d\n' % (chapter['end_time'] * 1000)
                    chapter_title = chapter.get('title')
                    if chapter_title:
                        metadata_file_content += 'title=%s\n' % ffmpeg_escape(chapter_title)
                f.write(metadata_file_content)
                in_filenames.append(metadata_filename)
                options.extend(['-map_metadata', '1'])

        self._downloader.to_screen('[ffmpeg] Adding metadata to \'%s\'' % filename)
        self.run_ffmpeg_multiple_files(in_filenames, temp_filename, options)
        if chapters:
            os.remove(metadata_filename)
        os.remove(encodeFilename(filename))
        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
        return [], info


class FFmpegMergerPP(FFmpegPostProcessor):
    def run(self, info):
        filename = info['filepath']
        temp_filename = prepend_extension(filename, 'temp')
        args = ['-c', 'copy', '-map', '0:v:0', '-map', '1:a:0']
        self._downloader.to_screen('[ffmpeg] Merging formats into "%s"' % filename)
        self.run_ffmpeg_multiple_files(info['__files_to_merge'], temp_filename, args)
        os.rename(encodeFilename(temp_filename), encodeFilename(filename))
        return info['__files_to_merge'], info

    def can_merge(self):
        # TODO: figure out merge-capable ffmpeg version
        if self.basename != 'avconv':
            return True

        required_version = '10-0'
        if is_outdated_version(
                self._versions[self.basename], required_version):
            warning = ('Your copy of %s is outdated and unable to properly mux separate video and audio files, '
                       'youtube-dl will download single file media. '
                       'Update %s to version %s or newer to fix this.') % (
                           self.basename, self.basename, required_version)
            if self._downloader:
                self._downloader.report_warning(warning)
            return False
        return True


class FFmpegFixupStretchedPP(FFmpegPostProcessor):
    def run(self, info):
        stretched_ratio = info.get('stretched_ratio')
        if stretched_ratio is None or stretched_ratio == 1:
            return [], info

        filename = info['filepath']
        temp_filename = prepend_extension(filename, 'temp')

        options = ['-c', 'copy', '-aspect', '%f' % stretched_ratio]
        self._downloader.to_screen('[ffmpeg] Fixing aspect ratio in "%s"' % filename)
        self.run_ffmpeg(filename, temp_filename, options)

        os.remove(encodeFilename(filename))
        os.rename(encodeFilename(temp_filename), encodeFilename(filename))

        return [], info


class FFmpegFixupM4aPP(FFmpegPostProcessor):
    def run(self, info):
        if info.get('container') != 'm4a_dash':
            return [], info

        filename = info['filepath']
        temp_filename = prepend_extension(filename, 'temp')

        options = ['-c', 'copy', '-f', 'mp4']
        self._downloader.to_screen('[ffmpeg] Correcting container in "%s"' % filename)
        self.run_ffmpeg(filename, temp_filename, options)

        os.remove(encodeFilename(filename))
        os.rename(encodeFilename(temp_filename), encodeFilename(filename))

        return [], info


class FFmpegFixupM3u8PP(FFmpegPostProcessor):
    def run(self, info):
        filename = info['filepath']
        if self.get_audio_codec(filename) == 'aac':
            temp_filename = prepend_extension(filename, 'temp')

            options = ['-c', 'copy', '-f', 'mp4', '-bsf:a', 'aac_adtstoasc']
            self._downloader.to_screen('[ffmpeg] Fixing malformed AAC bitstream in "%s"' % filename)
            self.run_ffmpeg(filename, temp_filename, options)

            os.remove(encodeFilename(filename))
            os.rename(encodeFilename(temp_filename), encodeFilename(filename))
        return [], info


class FFmpegSubtitlesConvertorPP(FFmpegPostProcessor):
    def __init__(self, downloader=None, format=None):
        super(FFmpegSubtitlesConvertorPP, self).__init__(downloader)
        self.format = format

    def run(self, info):
        subs = info.get('requested_subtitles')
        filename = info['filepath']
        new_ext = self.format
        new_format = new_ext
        if new_format == 'vtt':
            new_format = 'webvtt'
        if subs is None:
            self._downloader.to_screen('[ffmpeg] There aren\'t any subtitles to convert')
            return [], info
        self._downloader.to_screen('[ffmpeg] Converting subtitles')
        sub_filenames = []
        for lang, sub in subs.items():
            ext = sub['ext']
            if ext == new_ext:
                self._downloader.to_screen(
                    '[ffmpeg] Subtitle file for %s is already in the requested format' % new_ext)
                continue
            old_file = subtitles_filename(filename, lang, ext)
            sub_filenames.append(old_file)
            new_file = subtitles_filename(filename, lang, new_ext)

            if ext in ('dfxp', 'ttml', 'tt'):
                self._downloader.report_warning(
                    'You have requested to convert dfxp (TTML) subtitles into another format, '
                    'which results in style information loss')

                dfxp_file = old_file
                srt_file = subtitles_filename(filename, lang, 'srt')

                with open(dfxp_file, 'rb') as f:
                    srt_data = dfxp2srt(f.read())

                with io.open(srt_file, 'wt', encoding='utf-8') as f:
                    f.write(srt_data)
                old_file = srt_file

                subs[lang] = {
                    'ext': 'srt',
                    'data': srt_data
                }

                if new_ext == 'srt':
                    continue
                else:
                    sub_filenames.append(srt_file)

            self.run_ffmpeg(old_file, new_file, ['-f', new_format])

            with io.open(new_file, 'rt', encoding='utf-8') as f:
                subs[lang] = {
                    'ext': new_ext,
                    'data': f.read(),
                }

        return sub_filenames, info