hlsenc: Add encryption support
[libav.git] / doc / muxers.texi
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1@chapter Muxers
2@c man begin MUXERS
3
f8a45fa1 4Muxers are configured elements in Libav which allow writing
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5multimedia streams to a particular type of file.
6
f8a45fa1 7When you configure your Libav build, all the supported muxers
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8are enabled by default. You can list all available muxers using the
9configure option @code{--list-muxers}.
10
11You can disable all the muxers with the configure option
12@code{--disable-muxers} and selectively enable / disable single muxers
13with the options @code{--enable-muxer=@var{MUXER}} /
14@code{--disable-muxer=@var{MUXER}}.
15
202b5f6d 16The option @code{-formats} of the av* tools will display the list of
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17enabled muxers.
18
19A description of some of the currently available muxers follows.
20
77d4ed7a 21@anchor{crc}
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22@section crc
23
24CRC (Cyclic Redundancy Check) testing format.
25
26This muxer computes and prints the Adler-32 CRC of all the input audio
27and video frames. By default audio frames are converted to signed
2816-bit raw audio and video frames to raw video before computing the
29CRC.
30
31The output of the muxer consists of a single line of the form:
32CRC=0x@var{CRC}, where @var{CRC} is a hexadecimal number 0-padded to
338 digits containing the CRC for all the decoded input frames.
34
35For example to compute the CRC of the input, and store it in the file
36@file{out.crc}:
37@example
d5837d7f 38avconv -i INPUT -f crc out.crc
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39@end example
40
41You can print the CRC to stdout with the command:
42@example
d5837d7f 43avconv -i INPUT -f crc -
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44@end example
45
d5837d7f 46You can select the output format of each frame with @command{avconv} by
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47specifying the audio and video codec and format. For example to
48compute the CRC of the input audio converted to PCM unsigned 8-bit
49and the input video converted to MPEG-2 video, use the command:
50@example
d5837d7f 51avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f crc -
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52@end example
53
4c989761 54See also the @ref{framecrc} muxer.
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55
56@anchor{framecrc}
57@section framecrc
58
59Per-frame CRC (Cyclic Redundancy Check) testing format.
60
61This muxer computes and prints the Adler-32 CRC for each decoded audio
62and video frame. By default audio frames are converted to signed
6316-bit raw audio and video frames to raw video before computing the
64CRC.
65
66The output of the muxer consists of a line for each audio and video
67frame of the form: @var{stream_index}, @var{frame_dts},
68@var{frame_size}, 0x@var{CRC}, where @var{CRC} is a hexadecimal
69number 0-padded to 8 digits containing the CRC of the decoded frame.
70
71For example to compute the CRC of each decoded frame in the input, and
72store it in the file @file{out.crc}:
73@example
d5837d7f 74avconv -i INPUT -f framecrc out.crc
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75@end example
76
77You can print the CRC of each decoded frame to stdout with the command:
78@example
d5837d7f 79avconv -i INPUT -f framecrc -
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80@end example
81
d5837d7f 82You can select the output format of each frame with @command{avconv} by
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83specifying the audio and video codec and format. For example, to
84compute the CRC of each decoded input audio frame converted to PCM
85unsigned 8-bit and of each decoded input video frame converted to
86MPEG-2 video, use the command:
87@example
d5837d7f 88avconv -i INPUT -c:a pcm_u8 -c:v mpeg2video -f framecrc -
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89@end example
90
4c989761 91See also the @ref{crc} muxer.
77d4ed7a 92
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93@anchor{hls}
94@section hls
95
96Apple HTTP Live Streaming muxer that segments MPEG-TS according to
97the HTTP Live Streaming specification.
98
99It creates a playlist file and numbered segment files. The output
100filename specifies the playlist filename; the segment filenames
101receive the same basename as the playlist, a sequential number and
102a .ts extension.
103
104@example
105avconv -i in.nut out.m3u8
106@end example
107
108@table @option
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109@item -hls_time @var{seconds}
110Set the segment length in seconds.
111@item -hls_list_size @var{size}
112Set the maximum number of playlist entries.
113@item -hls_wrap @var{wrap}
114Set the number after which index wraps.
115@item -start_number @var{number}
116Start the sequence from @var{number}.
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117@item -hls_base_url @var{baseurl}
118Append @var{baseurl} to every entry in the playlist.
119Useful to generate playlists with absolute paths.
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120@item -hls_allow_cache @var{allowcache}
121Explicitly set whether the client MAY (1) or MUST NOT (0) cache media segments
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122@item -hls_version @var{version}
123Set the protocol version. Enables or disables version-specific features
124such as the integer (version 2) or decimal EXTINF values (version 3).
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125@item -hls_enc @var{enc}
126Enable (1) or disable (0) the AES128 encryption.
127When enabled every segment generated is encrypted and the encryption key
128is saved as @var{playlist name}.key.
129@item -hls_enc_key @var{key}
130Use the specified hex-coded 16byte key to encrypt the segments, by default it
131is randomly generated.
132@item -hls_enc_key_url @var{keyurl}
133If set, @var{keyurl} is prepended instead of @var{baseurl} to the key filename
134in the playlist.
135@item -hls_enc_iv @var{iv}
136Use a specified hex-coded 16byte initialization vector for every segment instead
137of the autogenerated ones.
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138@end table
139
02e8f032 140@anchor{image2}
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141@section image2
142
143Image file muxer.
144
0cad24ce 145The image file muxer writes video frames to image files.
e771d2e3 146
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147The output filenames are specified by a pattern, which can be used to
148produce sequentially numbered series of files.
149The pattern may contain the string "%d" or "%0@var{N}d", this string
e771d2e3 150specifies the position of the characters representing a numbering in
0cad24ce 151the filenames. If the form "%0@var{N}d" is used, the string
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152representing the number in each filename is 0-padded to @var{N}
153digits. The literal character '%' can be specified in the pattern with
154the string "%%".
155
156If the pattern contains "%d" or "%0@var{N}d", the first filename of
157the file list specified will contain the number 1, all the following
158numbers will be sequential.
159
160The pattern may contain a suffix which is used to automatically
161determine the format of the image files to write.
162
163For example the pattern "img-%03d.bmp" will specify a sequence of
164filenames of the form @file{img-001.bmp}, @file{img-002.bmp}, ...,
165@file{img-010.bmp}, etc.
166The pattern "img%%-%d.jpg" will specify a sequence of filenames of the
167form @file{img%-1.jpg}, @file{img%-2.jpg}, ..., @file{img%-10.jpg},
168etc.
169
d5837d7f 170The following example shows how to use @command{avconv} for creating a
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171sequence of files @file{img-001.jpeg}, @file{img-002.jpeg}, ...,
172taking one image every second from the input video:
173@example
d5837d7f 174avconv -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'
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175@end example
176
d5837d7f 177Note that with @command{avconv}, if the format is not specified with the
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178@code{-f} option and the output filename specifies an image file
179format, the image2 muxer is automatically selected, so the previous
180command can be written as:
181@example
d5837d7f 182avconv -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'
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183@end example
184
185Note 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
d5837d7f 189avconv -i in.avi -f image2 -frames:v 1 img.jpeg
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190@end example
191
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192@table @option
193@item -start_number @var{number}
194Start the sequence from @var{number}.
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195
196@item -update @var{number}
197If @var{number} is nonzero, the filename will always be interpreted as just a
198filename, not a pattern, and this file will be continuously overwritten with new
199images.
200
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201@end table
202
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203@section matroska
204
205Matroska container muxer.
206
207This muxer implements the matroska and webm container specs.
208
209The recognized metadata settings in this muxer are:
210
211@table @option
212
213@item title=@var{title name}
214Name provided to a single track
215@end table
216
217@table @option
218
219@item language=@var{language name}
220Specifies the language of the track in the Matroska languages form
221@end table
222
223@table @option
224
225@item STEREO_MODE=@var{mode}
226Stereo 3D video layout of two views in a single video track
227@table @option
228@item mono
229video is not stereo
230@item left_right
231Both views are arranged side by side, Left-eye view is on the left
232@item bottom_top
233Both views are arranged in top-bottom orientation, Left-eye view is at bottom
234@item top_bottom
235Both views are arranged in top-bottom orientation, Left-eye view is on top
236@item checkerboard_rl
237Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first
238@item checkerboard_lr
239Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first
240@item row_interleaved_rl
241Each view is constituted by a row based interleaving, Right-eye view is first row
242@item row_interleaved_lr
243Each view is constituted by a row based interleaving, Left-eye view is first row
244@item col_interleaved_rl
245Both views are arranged in a column based interleaving manner, Right-eye view is first column
246@item col_interleaved_lr
247Both views are arranged in a column based interleaving manner, Left-eye view is first column
248@item anaglyph_cyan_red
249All frames are in anaglyph format viewable through red-cyan filters
250@item right_left
251Both views are arranged side by side, Right-eye view is on the left
252@item anaglyph_green_magenta
253All frames are in anaglyph format viewable through green-magenta filters
254@item block_lr
255Both eyes laced in one Block, Left-eye view is first
256@item block_rl
257Both eyes laced in one Block, Right-eye view is first
258@end table
259@end table
260
261For example a 3D WebM clip can be created using the following command line:
262@example
263avconv -i sample_left_right_clip.mpg -an -c:v libvpx -metadata STEREO_MODE=left_right -y stereo_clip.webm
264@end example
265
266This muxer supports the following options:
267
268@table @option
269
270@item reserve_index_space
271By default, this muxer writes the index for seeking (called cues in Matroska
272terms) at the end of the file, because it cannot know in advance how much space
273to 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
275index at the beginning of the file.
276
277If this option is set to a non-zero value, the muxer will reserve a given amount
278of space in the file header and then try to write the cues there when the muxing
279finishes. If the available space does not suffice, muxing will fail. A safe size
280for most use cases should be about 50kB per hour of video.
281
282Note that cues are only written if the output is seekable and this option will
283have no effect if it is not.
284
285@end table
286
93632a70 287@section mov, mp4, ismv
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288
289The mov/mp4/ismv muxer supports fragmentation. Normally, a MOV/MP4
290file 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
292better playback using the @command{qt-faststart} tool). A fragmented
293file consists of a number of fragments, where packets and metadata
294about these packets are stored together. Writing a fragmented
295file has the advantage that the file is decodable even if the
296writing is interrupted (while a normal MOV/MP4 is undecodable if
297it is not properly finished), and it requires less memory when writing
298very long files (since writing normal MOV/MP4 files stores info about
299every single packet in memory until the file is closed). The downside
300is that it is less compatible with other applications.
301
302Fragmentation is enabled by setting one of the AVOptions that define
303how to cut the file into fragments:
304
305@table @option
306@item -movflags frag_keyframe
307Start a new fragment at each video keyframe.
308@item -frag_duration @var{duration}
309Create fragments that are @var{duration} microseconds long.
310@item -frag_size @var{size}
311Create fragments that contain up to @var{size} bytes of payload data.
312@item -movflags frag_custom
313Allow the caller to manually choose when to cut fragments, by
314calling @code{av_write_frame(ctx, NULL)} to write a fragment with
315the packets written so far. (This is only useful with other
316applications integrating libavformat, not from @command{avconv}.)
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317@item -min_frag_duration @var{duration}
318Don't create fragments that are shorter than @var{duration} microseconds long.
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319@end table
320
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321If more than one condition is specified, fragments are cut when
322one 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
324conditions to apply.
325
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326Additionally, the way the output file is written can be adjusted
327through a few other options:
328
329@table @option
330@item -movflags empty_moov
331Write an initial moov atom directly at the start of the file, without
332describing any samples in it. Generally, an mdat/moov pair is written
333at the start of the file, as a normal MOV/MP4 file, containing only
334a short portion of the file. With this option set, there is no initial
335mdat atom, and the moov atom only describes the tracks but has
336a zero duration.
337
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338This option is implicitly set when writing ismv (Smooth Streaming) files.
339@item -movflags separate_moof
340Write a separate moof (movie fragment) atom for each track. Normally,
341packets for all tracks are written in a moof atom (which is slightly
342more efficient), but with this option set, the muxer writes one moof/mdat
343pair for each track, making it easier to separate tracks.
344
345This option is implicitly set when writing ismv (Smooth Streaming) files.
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346@item -movflags faststart
347Run a second pass moving the index (moov atom) to the beginning of the file.
348This operation can take a while, and will not work in various situations such
349as fragmented output, thus it is not enabled by default.
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350@item -movflags disable_chpl
351Disable Nero chapter markers (chpl atom). Normally, both Nero chapters
352and a QuickTime chapter track are written to the file. With this option
353set, only the QuickTime chapter track will be written. Nero chapters can
354cause failures when the file is reprocessed with certain tagging programs.
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355@item -movflags omit_tfhd_offset
356Do not write any absolute base_data_offset in tfhd atoms. This avoids
357tying fragments to absolute byte positions in the file/streams.
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358@item -movflags default_base_moof
359Similarly to the omit_tfhd_offset, this flag avoids writing the
360absolute base_data_offset field in tfhd atoms, but does so by using
361the new default-base-is-moof flag instead. This flag is new from
36214496-12:2012. This may make the fragments easier to parse in certain
363circumstances (avoiding basing track fragment location calculations
364on the implicit end of the previous track fragment).
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365@end table
366
367Smooth Streaming content can be pushed in real time to a publishing
368point on IIS with this muxer. Example:
369@example
370avconv -re @var{<normal input/transcoding options>} -movflags isml+frag_keyframe -f ismv http://server/publishingpoint.isml/Streams(Encoder1)
371@end example
372
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373@section mp3
374
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375The MP3 muxer writes a raw MP3 stream with the following optional features:
376@itemize @bullet
377@item
378An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and
3792.4 are supported, the @code{id3v2_version} private option controls which one is
380used (3 or 4). Setting @code{id3v2_version} to 0 disables the ID3v2 header
381completely.
382
383The muxer supports writing attached pictures (APIC frames) to the ID3v2 header.
384The pictures are supplied to the muxer in form of a video stream with a single
385packet. There can be any number of those streams, each will correspond to a
386single APIC frame. The stream metadata tags @var{title} and @var{comment} map
387to APIC @var{description} and @var{picture type} respectively. See
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388@url{http://id3.org/id3v2.4.0-frames} for allowed picture types.
389
390Note that the APIC frames must be written at the beginning, so the muxer will
391buffer the audio frames until it gets all the pictures. It is therefore advised
392to provide the pictures as soon as possible to avoid excessive buffering.
393
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394@item
395A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by
396default, 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
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398various information that may be useful to the decoder, like the audio duration
399or encoder delay.
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400
401@item
402A legacy ID3v1 tag at the end of the file (disabled by default). It may be
403enabled with the @code{write_id3v1} private option, but as its capabilities are
404very limited, its usage is not recommended.
405@end itemize
406
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407Examples:
408
409Write an mp3 with an ID3v2.3 header and an ID3v1 footer:
410@example
411avconv -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3
412@end example
413
414Attach a picture to an mp3:
415@example
416avconv -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
419
420Write a "clean" MP3 without any extra features:
421@example
422avconv -i input.wav -write_xing 0 -id3v2_version 0 out.mp3
423@end example
424
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425@section mpegts
426
427MPEG transport stream muxer.
428
429This muxer implements ISO 13818-1 and part of ETSI EN 300 468.
430
431The muxer options are:
432
433@table @option
434@item -mpegts_original_network_id @var{number}
435Set the original_network_id (default 0x0001). This is unique identifier
436of a network in DVB. Its main use is in the unique identification of a
437service through the path Original_Network_ID, Transport_Stream_ID.
438@item -mpegts_transport_stream_id @var{number}
439Set the transport_stream_id (default 0x0001). This identifies a
440transponder in DVB.
441@item -mpegts_service_id @var{number}
442Set the service_id (default 0x0001) also known as program in DVB.
443@item -mpegts_pmt_start_pid @var{number}
444Set the first PID for PMT (default 0x1000, max 0x1f00).
445@item -mpegts_start_pid @var{number}
446Set the first PID for data packets (default 0x0100, max 0x0f00).
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447@item -muxrate @var{number}
448Set a constant muxrate (default VBR).
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449@item -pcr_period @var{numer}
450Override the default PCR retransmission time (default 20ms), ignored
451if variable muxrate is selected.
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452@end table
453
454The recognized metadata settings in mpegts muxer are @code{service_provider}
455and @code{service_name}. If they are not set the default for
6001dad6 456@code{service_provider} is "Libav" and the default for
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457@code{service_name} is "Service01".
458
459@example
d5837d7f 460avconv -i file.mpg -c copy \
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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
470
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471@section null
472
473Null muxer.
474
475This muxer does not generate any output file, it is mainly useful for
476testing or benchmarking purposes.
477
d5837d7f 478For example to benchmark decoding with @command{avconv} you can use the
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479command:
480@example
d5837d7f 481avconv -benchmark -i INPUT -f null out.null
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482@end example
483
484Note that the above command does not read or write the @file{out.null}
d5837d7f 485file, but specifying the output file is required by the @command{avconv}
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486syntax.
487
488Alternatively you can write the command as:
489@example
d5837d7f 490avconv -benchmark -i INPUT -f null -
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491@end example
492
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493@section nut
494
495@table @option
496@item -syncpoints @var{flags}
497Change 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
503The @var{none} and @var{timestamped} flags are experimental.
504@end table
505
506@example
507avconv -i INPUT -f_strict experimental -syncpoints none - | processor
508@end example
509
a7b3216c 510@section ogg
945dda41 511
a7b3216c 512Ogg container muxer.
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513
514@table @option
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515@item -page_duration @var{duration}
516Preferred page duration, in microseconds. The muxer will attempt to create
517pages that are approximately @var{duration} microseconds long. This allows the
518user to compromise between seek granularity and container overhead. The default
519is 1 second. A value of 0 will fill all segments, making pages as large as
520possible. A value of 1 will effectively use 1 packet-per-page in most
521situations, giving a small seek granularity at the cost of additional container
522overhead.
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523@item -serial_offset @var{value}
524Serial value from which to set the streams serial number.
525Setting it to different and sufficiently large values ensures that the produced
526ogg files can be safely chained.
527
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528@end table
529
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530@section segment
531
532Basic stream segmenter.
533
534The segmenter muxer outputs streams to a number of separate files of nearly
535fixed duration. Output filename pattern can be set in a fashion similar to
536@ref{image2}.
537
538Every segment starts with a video keyframe, if a video stream is present.
539The segment muxer works best with a single constant frame rate video.
540
541Optionally it can generate a flat list of the created segments, one segment
542per line.
543
544@table @option
545@item segment_format @var{format}
546Override the inner container format, by default it is guessed by the filename
547extension.
548@item segment_time @var{t}
549Set segment duration to @var{t} seconds.
550@item segment_list @var{name}
551Generate also a listfile named @var{name}.
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552@item segment_list_type @var{type}
553Select 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
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558@item segment_list_size @var{size}
559Overwrite the listfile once it reaches @var{size} entries.
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560@item segment_list_entry_prefix @var{prefix}
561Prepend @var{prefix} to each entry. Useful to generate absolute paths.
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562@item segment_wrap @var{limit}
563Wrap around segment index once it reaches @var{limit}.
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564@end table
565
566@example
567avconv -i in.mkv -c copy -map 0 -f segment -list out.list out%03d.nut
568@end example
569
85466e1e 570@c man end MUXERS