hlsenc: Add encryption support
[libav.git] / doc / muxers.texi
1 @chapter Muxers
2 @c man begin MUXERS
4 Muxers are configured elements in Libav which allow writing
5 multimedia streams to a particular type of file.
7 When you configure your Libav build, all the supported muxers
8 are enabled by default. You can list all available muxers using the
9 configure option @code{--list-muxers}.
11 You can disable all the muxers with the configure option
12 @code{--disable-muxers} and selectively enable / disable single muxers
13 with the options @code{--enable-muxer=@var{MUXER}} /
14 @code{--disable-muxer=@var{MUXER}}.
16 The option @code{-formats} of the av* tools will display the list of
17 enabled muxers.
19 A description of some of the currently available muxers follows.
21 @anchor{crc}
22 @section crc
24 CRC (Cyclic Redundancy Check) testing format.
26 This muxer computes and prints the Adler-32 CRC of all the input audio
27 and video frames. By default audio frames are converted to signed
28 16-bit raw audio and video frames to raw video before computing the
29 CRC.
31 The output of the muxer consists of a single line of the form:
32 CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
33 8 digits containing the CRC for all the decoded input frames.
35 For example to compute the CRC of the input, and store it in the file
36 @file{out.crc}:
37 @example
38 avconv -i INPUT -f crc out.crc
39 @end example
41 You can print the CRC to stdout with the command:
42 @example
43 avconv -i INPUT -f crc -
44 @end example
46 You can select the output format of each frame with @command{avconv} by
47 specifying the audio and video codec and format. For example to
48 compute the CRC of the input audio converted to PCM unsigned 8-bit
49 and the input video converted to MPEG-2 video, use the command:
50 @example
51 avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
52 @end example
54 See also the @ref{framecrc} muxer.
56 @anchor{framecrc}
57 @section framecrc
59 Per-frame CRC (Cyclic Redundancy Check) testing format.
61 This muxer computes and prints the Adler-32 CRC for each decoded audio
62 and video frame. By default audio frames are converted to signed
63 16-bit raw audio and video frames to raw video before computing the
64 CRC.
66 The output of the muxer consists of a line for each audio and video
67 frame of the form: @var{stream_index}, @var{frame_dts},
68 @var{frame_size}, 0x@var{CRC}, where @var{CRC} is a hexadecimal
69 number 0-padded to 8 digits containing the CRC of the decoded frame.
71 For example to compute the CRC of each decoded frame in the input, and
72 store it in the file @file{out.crc}:
73 @example
74 avconv -i INPUT -f framecrc out.crc
75 @end example
77 You can print the CRC of each decoded frame to stdout with the command:
78 @example
79 avconv -i INPUT -f framecrc -
80 @end example
82 You can select the output format of each frame with @command{avconv} by
83 specifying the audio and video codec and format. For example, to
84 compute the CRC of each decoded input audio frame converted to PCM
85 unsigned 8-bit and of each decoded input video frame converted to
86 MPEG-2 video, use the command:
87 @example
88 avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
89 @end example
91 See also the @ref{crc} muxer.
93 @anchor{hls}
94 @section hls
96 Apple HTTP Live Streaming muxer that segments MPEG-TS according to
97 the HTTP Live Streaming specification.
99 It creates a playlist file and numbered segment files. The output
100 filename specifies the playlist filename; the segment filenames
101 receive the same basename as the playlist, a sequential number and
102 a .ts extension.
104 @example
105 avconv -i in.nut out.m3u8
106 @end example
108 @table @option
109 @item -hls_time @var{seconds}
110 Set the segment length in seconds.
111 @item -hls_list_size @var{size}
112 Set the maximum number of playlist entries.
113 @item -hls_wrap @var{wrap}
114 Set the number after which index wraps.
115 @item -start_number @var{number}
116 Start the sequence from @var{number}.
117 @item -hls_base_url @var{baseurl}
118 Append @var{baseurl} to every entry in the playlist.
119 Useful to generate playlists with absolute paths.
120 @item -hls_allow_cache @var{allowcache}
121 Explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments
122 @item -hls_version @var{version}
123 Set the protocol version. Enables or disables version-specific features
124 such as the integer (version 2) or decimal EXTINF values (version 3).
125 @item -hls_enc @var{enc}
126 Enable (1) or disable (0) the AES128 encryption.
127 When enabled every segment generated is encrypted and the encryption key
128 is saved as @var{playlist name}.key.
129 @item -hls_enc_key @var{key}
130 Use the specified hex-coded 16byte key to encrypt the segments, by default it
131 is randomly generated.
132 @item -hls_enc_key_url @var{keyurl}
133 If set, @var{keyurl} is prepended instead of @var{baseurl} to the key filename
134 in the playlist.
135 @item -hls_enc_iv @var{iv}
136 Use a specified hex-coded 16byte initialization vector for every segment instead
137 of the autogenerated ones.
138 @end table
140 @anchor{image2}
141 @section image2
143 Image file muxer.
145 The image file muxer writes video frames to image files.
147 The output filenames are specified by a pattern, which can be used to
148 produce sequentially numbered series of files.
149 The pattern may contain the string "%d" or "%0@var{N}d", this string
150 specifies the position of the characters representing a numbering in
151 the filenames. If the form "%0@var{N}d" is used, the string
152 representing the number in each filename is 0-padded to @var{N}
153 digits. The literal character '%' can be specified in the pattern with
154 the string "%%".
156 If the pattern contains "%d" or "%0@var{N}d", the first filename of
157 the file list specified will contain the number 1, all the following
158 numbers will be sequential.
160 The pattern may contain a suffix which is used to automatically
161 determine the format of the image files to write.
163 For example the pattern "img-%03d.bmp" will specify a sequence of
164 filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
165 @file{img-010.bmp}, etc.
166 The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
167 form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
168 etc.
170 The following example shows how to use @command{avconv} for creating a
171 sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
172 taking one image every second from the input video:
173 @example
174 avconv -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
175 @end example
177 Note that with @command{avconv}, if the format is not specified with the
178 @code{-f} option and the output filename specifies an image file
179 format, the image2 muxer is automatically selected, so the previous
180 command can be written as:
181 @example
182 avconv -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
183 @end example
185 Note also that the pattern must not necessarily contain "%d" or
186 "%0@var{N}d", for example to create a single image file
187 @file{img.jpeg} from the input video you can employ the command:
188 @example
189 avconv -i in.avi -f image2 -frames:v 1 img.jpeg
190 @end example
192 @table @option
193 @item -start_number @var{number}
194 Start the sequence from @var{number}.
196 @item -update @var{number}
197 If @var{number} is nonzero, the filename will always be interpreted as just a
198 filename, not a pattern, and this file will be continuously overwritten with new
199 images.
201 @end table
203 @section matroska
205 Matroska container muxer.
207 This muxer implements the matroska and webm container specs.
209 The recognized metadata settings in this muxer are:
211 @table @option
213 @item title=@var{title name}
214 Name provided to a single track
215 @end table
217 @table @option
219 @item language=@var{language name}
220 Specifies the language of the track in the Matroska languages form
221 @end table
223 @table @option
225 @item STEREO_MODE=@var{mode}
226 Stereo 3D video layout of two views in a single video track
227 @table @option
228 @item mono
229 video is not stereo
230 @item left_right
231 Both views are arranged side by side, Left-eye view is on the left
232 @item bottom_top
233 Both views are arranged in top-bottom orientation, Left-eye view is at bottom
234 @item top_bottom
235 Both views are arranged in top-bottom orientation, Left-eye view is on top
236 @item checkerboard_rl
237 Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
238 @item checkerboard_lr
239 Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
240 @item row_interleaved_rl
241 Each view is constituted by a row based interleaving, Right-eye view is first row
242 @item row_interleaved_lr
243 Each view is constituted by a row based interleaving, Left-eye view is first row
244 @item col_interleaved_rl
245 Both views are arranged in a column based interleaving manner, Right-eye view is first column
246 @item col_interleaved_lr
247 Both views are arranged in a column based interleaving manner, Left-eye view is first column
248 @item anaglyph_cyan_red
249 All frames are in anaglyph format viewable through red-cyan filters
250 @item right_left
251 Both views are arranged side by side, Right-eye view is on the left
252 @item anaglyph_green_magenta
253 All frames are in anaglyph format viewable through green-magenta filters
254 @item block_lr
255 Both eyes laced in one Block, Left-eye view is first
256 @item block_rl
257 Both eyes laced in one Block, Right-eye view is first
258 @end table
259 @end table
261 For example a 3D WebM clip can be created using the following command line:
262 @example
263 avconv -i sample_left_right_clip.mpg -an -c:v libvpx -metadata STEREO_MODE=left_right -y stereo_clip.webm
264 @end example
266 This muxer supports the following options:
268 @table @option
270 @item reserve_index_space
271 By default, this muxer writes the index for seeking (called cues in Matroska
272 terms) at the end of the file, because it cannot know in advance how much space
273 to leave for the index at the beginning of the file. However for some use cases
274 -- e.g. streaming where seeking is possible but slow -- it is useful to put the
275 index at the beginning of the file.
277 If this option is set to a non-zero value, the muxer will reserve a given amount
278 of space in the file header and then try to write the cues there when the muxing
279 finishes. If the available space does not suffice, muxing will fail. A safe size
280 for most use cases should be about 50kB per hour of video.
282 Note that cues are only written if the output is seekable and this option will
283 have no effect if it is not.
285 @end table
287 @section mov, mp4, ismv
289 The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
290 file has all the metadata about all packets stored in one location
291 (written at the end of the file, it can be moved to the start for
292 better playback using the @command{qt-faststart} tool). A fragmented
293 file consists of a number of fragments, where packets and metadata
294 about these packets are stored together. Writing a fragmented
295 file has the advantage that the file is decodable even if the
296 writing is interrupted (while a normal MOV/MP4 is undecodable if
297 it is not properly finished), and it requires less memory when writing
298 very long files (since writing normal MOV/MP4 files stores info about
299 every single packet in memory until the file is closed). The downside
300 is that it is less compatible with other applications.
302 Fragmentation is enabled by setting one of the AVOptions that define
303 how to cut the file into fragments:
305 @table @option
306 @item -movflags frag_keyframe
307 Start a new fragment at each video keyframe.
308 @item -frag_duration @var{duration}
309 Create fragments that are @var{duration} microseconds long.
310 @item -frag_size @var{size}
311 Create fragments that contain up to @var{size} bytes of payload data.
312 @item -movflags frag_custom
313 Allow the caller to manually choose when to cut fragments, by
314 calling @code{av_write_frame(ctx, NULL)} to write a fragment with
315 the packets written so far. (This is only useful with other
316 applications integrating libavformat, not from @command{avconv}.)
317 @item -min_frag_duration @var{duration}
318 Don't create fragments that are shorter than @var{duration} microseconds long.
319 @end table
321 If more than one condition is specified, fragments are cut when
322 one of the specified conditions is fulfilled. The exception to this is
323 @code{-min_frag_duration}, which has to be fulfilled for any of the other
324 conditions to apply.
326 Additionally, the way the output file is written can be adjusted
327 through a few other options:
329 @table @option
330 @item -movflags empty_moov
331 Write an initial moov atom directly at the start of the file, without
332 describing any samples in it. Generally, an mdat/moov pair is written
333 at the start of the file, as a normal MOV/MP4 file, containing only
334 a short portion of the file. With this option set, there is no initial
335 mdat atom, and the moov atom only describes the tracks but has
336 a zero duration.
338 This option is implicitly set when writing ismv (Smooth Streaming) files.
339 @item -movflags separate_moof
340 Write a separate moof (movie fragment) atom for each track. Normally,
341 packets for all tracks are written in a moof atom (which is slightly
342 more efficient), but with this option set, the muxer writes one moof/mdat
343 pair for each track, making it easier to separate tracks.
345 This option is implicitly set when writing ismv (Smooth Streaming) files.
346 @item -movflags faststart
347 Run a second pass moving the index (moov atom) to the beginning of the file.
348 This operation can take a while, and will not work in various situations such
349 as fragmented output, thus it is not enabled by default.
350 @item -movflags disable_chpl
351 Disable Nero chapter markers (chpl atom). Normally, both Nero chapters
352 and a QuickTime chapter track are written to the file. With this option
353 set, only the QuickTime chapter track will be written. Nero chapters can
354 cause failures when the file is reprocessed with certain tagging programs.
355 @item -movflags omit_tfhd_offset
356 Do not write any absolute base_data_offset in tfhd atoms. This avoids
357 tying fragments to absolute byte positions in the file/streams.
358 @item -movflags default_base_moof
359 Similarly to the omit_tfhd_offset, this flag avoids writing the
360 absolute base_data_offset field in tfhd atoms, but does so by using
361 the new default-base-is-moof flag instead. This flag is new from
362 14496-12:2012. This may make the fragments easier to parse in certain
363 circumstances (avoiding basing track fragment location calculations
364 on the implicit end of the previous track fragment).
365 @end table
367 Smooth Streaming content can be pushed in real time to a publishing
368 point on IIS with this muxer. Example:
369 @example
370 avconv -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
371 @end example
373 @section mp3
375 The MP3 muxer writes a raw MP3 stream with the following optional features:
376 @itemize @bullet
377 @item
378 An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and
379 2.4 are supported, the @code{id3v2_version} private option controls which one is
380 used (3 or 4). Setting @code{id3v2_version} to 0 disables the ID3v2 header
381 completely.
383 The muxer supports writing attached pictures (APIC frames) to the ID3v2 header.
384 The pictures are supplied to the muxer in form of a video stream with a single
385 packet. There can be any number of those streams, each will correspond to a
386 single APIC frame. The stream metadata tags @var{title} and @var{comment} map
387 to APIC @var{description} and @var{picture type} respectively. See
388 @url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
390 Note that the APIC frames must be written at the beginning, so the muxer will
391 buffer the audio frames until it gets all the pictures. It is therefore advised
392 to provide the pictures as soon as possible to avoid excessive buffering.
394 @item
395 A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by
396 default, but will be written only if the output is seekable. The
397 @code{write_xing} private option can be used to disable it. The frame contains
398 various information that may be useful to the decoder, like the audio duration
399 or encoder delay.
401 @item
402 A legacy ID3v1 tag at the end of the file (disabled by default). It may be
403 enabled with the @code{write_id3v1} private option, but as its capabilities are
404 very limited, its usage is not recommended.
405 @end itemize
407 Examples:
409 Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
410 @example
411 avconv -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
412 @end example
414 Attach a picture to an mp3:
415 @example
416 avconv -i input.mp3 -i cover.png -c copy -metadata:s:v title="Album cover"
417 -metadata:s:v comment="Cover (Front)" out.mp3
418 @end example
420 Write a "clean" MP3 without any extra features:
421 @example
422 avconv -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
423 @end example
425 @section mpegts
427 MPEG transport stream muxer.
429 This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
431 The muxer options are:
433 @table @option
434 @item -mpegts_original_network_id @var{number}
435 Set the original_network_id (default 0x0001). This is unique identifier
436 of a network in DVB. Its main use is in the unique identification of a
437 service through the path Original_Network_ID, Transport_Stream_ID.
438 @item -mpegts_transport_stream_id @var{number}
439 Set the transport_stream_id (default 0x0001). This identifies a
440 transponder in DVB.
441 @item -mpegts_service_id @var{number}
442 Set the service_id (default 0x0001) also known as program in DVB.
443 @item -mpegts_pmt_start_pid @var{number}
444 Set the first PID for PMT (default 0x1000, max 0x1f00).
445 @item -mpegts_start_pid @var{number}
446 Set the first PID for data packets (default 0x0100, max 0x0f00).
447 @item -muxrate @var{number}
448 Set a constant muxrate (default VBR).
449 @item -pcr_period @var{numer}
450 Override the default PCR retransmission time (default 20ms), ignored
451 if variable muxrate is selected.
452 @end table
454 The recognized metadata settings in mpegts muxer are @code{service_provider}
455 and @code{service_name}. If they are not set the default for
456 @code{service_provider} is "Libav" and the default for
457 @code{service_name} is "Service01".
459 @example
460 avconv -i file.mpg -c copy \
461 -mpegts_original_network_id 0x1122 \
462 -mpegts_transport_stream_id 0x3344 \
463 -mpegts_service_id 0x5566 \
464 -mpegts_pmt_start_pid 0x1500 \
465 -mpegts_start_pid 0x150 \
466 -metadata service_provider="Some provider" \
467 -metadata service_name="Some Channel" \
468 -y out.ts
469 @end example
471 @section null
473 Null muxer.
475 This muxer does not generate any output file, it is mainly useful for
476 testing or benchmarking purposes.
478 For example to benchmark decoding with @command{avconv} you can use the
479 command:
480 @example
481 avconv -benchmark -i INPUT -f null out.null
482 @end example
484 Note that the above command does not read or write the @file{out.null}
485 file, but specifying the output file is required by the @command{avconv}
486 syntax.
488 Alternatively you can write the command as:
489 @example
490 avconv -benchmark -i INPUT -f null -
491 @end example
493 @section nut
495 @table @option
496 @item -syncpoints @var{flags}
497 Change the syncpoint usage in nut:
498 @table @option
499 @item @var{default} use the normal low-overhead seeking aids.
500 @item @var{none} do not use the syncpoints at all, reducing the overhead but making the stream non-seekable;
501 @item @var{timestamped} extend the syncpoint with a wallclock field.
502 @end table
503 The @var{none} and @var{timestamped} flags are experimental.
504 @end table
506 @example
507 avconv -i INPUT -f_strict experimental -syncpoints none - | processor
508 @end example
510 @section ogg
512 Ogg container muxer.
514 @table @option
515 @item -page_duration @var{duration}
516 Preferred page duration, in microseconds. The muxer will attempt to create
517 pages that are approximately @var{duration} microseconds long. This allows the
518 user to compromise between seek granularity and container overhead. The default
519 is 1 second. A value of 0 will fill all segments, making pages as large as
520 possible. A value of 1 will effectively use 1 packet-per-page in most
521 situations, giving a small seek granularity at the cost of additional container
522 overhead.
523 @item -serial_offset @var{value}
524 Serial value from which to set the streams serial number.
525 Setting it to different and sufficiently large values ensures that the produced
526 ogg files can be safely chained.
528 @end table
530 @section segment
532 Basic stream segmenter.
534 The segmenter muxer outputs streams to a number of separate files of nearly
535 fixed duration. Output filename pattern can be set in a fashion similar to
536 @ref{image2}.
538 Every segment starts with a video keyframe, if a video stream is present.
539 The segment muxer works best with a single constant frame rate video.
541 Optionally it can generate a flat list of the created segments, one segment
542 per line.
544 @table @option
545 @item segment_format @var{format}
546 Override the inner container format, by default it is guessed by the filename
547 extension.
548 @item segment_time @var{t}
549 Set segment duration to @var{t} seconds.
550 @item segment_list @var{name}
551 Generate also a listfile named @var{name}.
552 @item segment_list_type @var{type}
553 Select the listing format.
554 @table @option
555 @item @var{flat} use a simple flat list of entries.
556 @item @var{hls} use a m3u8-like structure.
557 @end table
558 @item segment_list_size @var{size}
559 Overwrite the listfile once it reaches @var{size} entries.
560 @item segment_list_entry_prefix @var{prefix}
561 Prepend @var{prefix} to each entry. Useful to generate absolute paths.
562 @item segment_wrap @var{limit}
563 Wrap around segment index once it reaches @var{limit}.
564 @end table
566 @example
567 avconv -i in.mkv -c copy -map 0 -f segment -list out.list out%03d.nut
568 @end example
570 @c man end MUXERS