Key info file format:

        <key URI>
        <key file path>
        <IV> (optional)

Example key URIs:

        server/file.key
        /path/to/file.key
        file.key

Example key file paths:

        file.key
        /path/to/file.key

Example

        0123456789ABCDEF0123456789ABCDEF

Key info file example:

        server/file.key
        /path/to/file.key
        0123456789ABCDEF0123456789ABCDEF

Example shell script:

        #!/bin/sh
        BASE_URL=${1:-'.'}
        openssl rand 16 > file.key
        echo $BASE_URL/file.key > file.keyinfo
        echo file.key >> file.keyinfo
        echo $(openssl rand -hex 16) >> file.keyinfo
        ffmpeg -f lavfi -re -i testsrc -c:v h264 -hls_flags delete_segments \
          -hls_key_info_file file.keyinfo out.m3u8

        ffmpeg -i in.nut -hls_flags single_file out.m3u8

Will produce the playlist, out.m3u8, and a single segment file, out.ts.

ico

Microsoft's icon file format (

*

Size cannot exceed 256 pixels in any dimension

*

Only

BMP

and

PNG

images can be stored

*

If a

BMP

image is used, it must be one of the following pixel formats:

        BMP Bit Depth      FFmpeg Pixel Format
        1bit               pal8
        4bit               pal8
        8bit               pal8
        16bit              rgb555le
        24bit              bgr24
        32bit              bgra

*

If a

BMP

image is used, it must use the

BITMAPINFOHEADER DIB

header

*

If a

PNG

image is used, it must use the rgba pixel format

image2

The image file muxer writes video frames to image files.

The output filenames are specified by a pattern, which can be used to produce sequentially numbered series of files. The pattern may contain the string ``%d'' or "%0Nd``, this string specifies the position of the characters representing a numbering in the filenames. If the form ''%0Nd" is used, the string representing the number in each filename is 0-padded to N digits. The literal character '%' can be specified in the pattern with the string ``%%''.

If the pattern contains ``%d'' or "%0Nd", the first filename of the file list specified will contain the number 1, all the following numbers will be sequential.

The pattern may contain a suffix which is used to automatically determine the format of the image files to write.

For example the pattern ``img-%03d.bmp'' will specify a sequence of filenames of the form img-001.bmp, img-002.bmp, ..., img-010.bmp, etc. The pattern ``img%%-%d.jpg'' will specify a sequence of filenames of the form img%-1.jpg, img%-2.jpg, ..., img%-10.jpg, etc.

Examples

The following example shows how to use ffmpeg for creating a sequence of files img-001.jpeg, img-002.jpeg, ..., taking one image every second from the input video:

        ffmpeg -i in.avi -vsync 1 -r 1 -f image2 'img-%03d.jpeg'

Note that with ffmpeg, if the format is not specified with the "-f" option and the output filename specifies an image file format, the image2 muxer is automatically selected, so the previous command can be written as:

        ffmpeg -i in.avi -vsync 1 -r 1 'img-%03d.jpeg'

Note also that the pattern must not necessarily contain ``%d'' or "%0Nd", for example to create a single image file img.jpeg from the input video you can employ the command:

        ffmpeg -i in.avi -f image2 -frames:v 1 img.jpeg

The strftime option allows you to expand the filename with date and time information. Check the documentation of the "strftime()" function for the syntax.

For example to generate image files from the "strftime()" ``%Y-%m-%d_%H-%M-%S'' pattern, the following ffmpeg command can be used:

        ffmpeg -f v4l2 -r 1 -i /dev/video0 -f image2 -strftime 1 "%Y-%m-%d_%H-%M-%S.jpg"

Options

start_number

Start the sequence from the specified number. Default value is 0.

update

If set to 1, the filename will always be interpreted as just a filename, not a pattern, and the corresponding file will be continuously overwritten with new images. Default value is 0.

strftime

If set to 1, expand the filename with date and time information from "strftime()". Default value is 0.

The image muxer supports the .Y.U.V image file format. This format is special in that that each image frame consists of three files, for each of the

matroska

This muxer implements the matroska and webm container specs.

Metadata

The recognized metadata settings in this muxer are:

title

Set title name provided to a single track.

language

Specify the language of the track in the Matroska languages form.

The language can be either the 3 letters bibliographic

ISO-639-2

(

ISO 639-2/B

) form (like ``fre'' for French), or a language code mixed with a country code for specialities in languages (like ``fre-ca'' for Canadian French).

stereo_mode

Set stereo 3D video layout of two views in a single video track.

The following values are recognized:

mono

video is not stereo

left_right

Both views are arranged side by side, Left-eye view is on the left

bottom_top

Both views are arranged in top-bottom orientation, Left-eye view is at bottom

top_bottom

Both views are arranged in top-bottom orientation, Left-eye view is on top

checkerboard_rl

Each view is arranged in a checkerboard interleaved pattern, Left-eye view being first

checkerboard_lr

Each view is arranged in a checkerboard interleaved pattern, Right-eye view being first

row_interleaved_rl

Each view is constituted by a row based interleaving, Right-eye view is first row

row_interleaved_lr

Each view is constituted by a row based interleaving, Left-eye view is first row

col_interleaved_rl

Both views are arranged in a column based interleaving manner, Right-eye view is first column

col_interleaved_lr

Both views are arranged in a column based interleaving manner, Left-eye view is first column

anaglyph_cyan_red

All frames are in anaglyph format viewable through red-cyan filters

right_left

Both views are arranged side by side, Right-eye view is on the left

anaglyph_green_magenta

All frames are in anaglyph format viewable through green-magenta filters

block_lr

Both eyes laced in one Block, Left-eye view is first

block_rl

Both eyes laced in one Block, Right-eye view is first

For example a 3D WebM clip can be created using the following command line:

        ffmpeg -i sample_left_right_clip.mpg -an -c:v libvpx -metadata stereo_mode=left_right -y stereo_clip.webm

Options

This muxer supports the following options:

reserve_index_space

By default, this muxer writes the index for seeking (called cues in Matroska terms) at the end of the file, because it cannot know in advance how much space to leave for the index at the beginning of the file. However for some use cases --- e.g. streaming where seeking is possible but slow --- it is useful to put the index at the beginning of the file.

If this option is set to a non-zero value, the muxer will reserve a given amount of space in the file header and then try to write the cues there when the muxing finishes. If the available space does not suffice, muxing will fail. A safe size for most use cases should be about 50kB per hour of video.

Note that cues are only written if the output is seekable and this option will have no effect if it is not.

md5

This muxer computes and prints the

The output of the muxer consists of a single line of the form: MD5=

For example to compute the

        ffmpeg -i INPUT -f md5 out.md5

You can print the

        ffmpeg -i INPUT -f md5 -

See also the framemd5 muxer.

mov, mp4, ismv

The mov/mp4/ismv muxer supports fragmentation. Normally, a

Options

Fragmentation is enabled by setting one of the AVOptions that define how to cut the file into fragments:

-moov_size bytes

Reserves space for the moov atom at the beginning of the file instead of placing the moov atom at the end. If the space reserved is insufficient, muxing will fail.

-movflags frag_keyframe

Start a new fragment at each video keyframe.

-frag_duration duration

Create fragments that are duration microseconds long.

-frag_size size

Create fragments that contain up to size bytes of payload data.

-movflags frag_custom

Allow the caller to manually choose when to cut fragments, by calling "av_write_frame(ctx, NULL)" to write a fragment with the packets written so far. (This is only useful with other applications integrating libavformat, not from ffmpeg.)

-min_frag_duration duration

Don't create fragments that are shorter than duration microseconds long.

If more than one condition is specified, fragments are cut when one of the specified conditions is fulfilled. The exception to this is "-min_frag_duration", which has to be fulfilled for any of the other conditions to apply.

Additionally, the way the output file is written can be adjusted through a few other options:

-movflags empty_moov

Write an initial moov atom directly at the start of the file, without describing any samples in it. Generally, an mdat/moov pair is written at the start of the file, as a normal

MOV/MP4

file, containing only a short portion of the file. With this option set, there is no initial mdat atom, and the moov atom only describes the tracks but has a zero duration.

This option is implicitly set when writing ismv (Smooth Streaming) files.

-movflags separate_moof

Write a separate moof (movie fragment) atom for each track. Normally, packets for all tracks are written in a moof atom (which is slightly more efficient), but with this option set, the muxer writes one moof/mdat pair for each track, making it easier to separate tracks.

This option is implicitly set when writing ismv (Smooth Streaming) files.

-movflags faststart

Run a second pass moving the index (moov atom) to the beginning of the file. This operation can take a while, and will not work in various situations such as fragmented output, thus it is not enabled by default.

-movflags rtphint

Add

RTP

hinting tracks to the output file.

-movflags disable_chpl

Disable Nero chapter markers (chpl atom). Normally, both Nero chapters and a QuickTime chapter track are written to the file. With this option set, only the QuickTime chapter track will be written. Nero chapters can cause failures when the file is reprocessed with certain tagging programs, like mp3Tag 2.61a and iTunes 11.3, most likely other versions are affected as well.

-movflags omit_tfhd_offset

Do not write any absolute base_data_offset in tfhd atoms. This avoids tying fragments to absolute byte positions in the file/streams.

-movflags default_base_moof

Similarly to the omit_tfhd_offset, this flag avoids writing the absolute base_data_offset field in tfhd atoms, but does so by using the new default-base-is-moof flag instead. This flag is new from 14496-12:2012. This may make the fragments easier to parse in certain circumstances (avoiding basing track fragment location calculations on the implicit end of the previous track fragment).

Example

Smooth Streaming content can be pushed in real time to a publishing point on

        ffmpeg -re <<normal input/transcoding options>> -movflags isml+frag_keyframe -f ismv server/publishingpoint.isml/Streams(Encoder1

Audible

Audible

        ffmpeg -activation_bytes 1CEB00DA -i test.aax -vn -c:a copy output.mp4

mp3

*

An ID3v2 metadata header at the beginning (enabled by default). Versions 2.3 and 2.4 are supported, the "id3v2_version" private option controls which one is used (3 or 4). Setting "id3v2_version" to 0 disables the ID3v2 header completely.

The muxer supports writing attached pictures (

APIC

frames) to the ID3v2 header. The pictures are supplied to the muxer in form of a video stream with a single packet. There can be any number of those streams, each will correspond to a single

APIC

frame. The stream metadata tags title and comment map to

APIC

description and picture type respectively. See <id3.org/id3v2.4.0-frames> for allowed picture types.

Note that the

APIC

frames must be written at the beginning, so the muxer will buffer the audio frames until it gets all the pictures. It is therefore advised to provide the pictures as soon as possible to avoid excessive buffering.

*

A Xing/LAME frame right after the ID3v2 header (if present). It is enabled by default, but will be written only if the output is seekable. The "write_xing" private option can be used to disable it. The frame contains various information that may be useful to the decoder, like the audio duration or encoder delay.

*

A legacy ID3v1 tag at the end of the file (disabled by default). It may be enabled with the "write_id3v1" private option, but as its capabilities are very limited, its usage is not recommended.

Examples:

Write an mp3 with an ID3v2.3 header and an ID3v1 footer:

        ffmpeg -i INPUT -id3v2_version 3 -write_id3v1 1 out.mp3

To attach a picture to an mp3 file select both the audio and the picture stream with "map":

        ffmpeg -i input.mp3 -i cover.png -c copy -map 0 -map 1
        -metadata:s:v title="Album cover" -metadata:s:v comment="Cover (Front)" out.mp3

Write a ``clean''

        ffmpeg -i input.wav -write_xing 0 -id3v2_version 0 out.mp3

mpegts

This muxer implements

The recognized metadata settings in mpegts muxer are "service_provider" and "service_name". If they are not set the default for "service_provider" is ``FFmpeg'' and the default for "service_name" is ``Service01''.

Options

The muxer options are:

-mpegts_original_network_id number

Set the original_network_id (default 0x0001). This is unique identifier of a network in

DVB.

Its main use is in the unique identification of a service through the path Original_Network_ID, Transport_Stream_ID.

-mpegts_transport_stream_id number

Set the transport_stream_id (default 0x0001). This identifies a transponder in

DVB.

-mpegts_service_id number

Set the service_id (default 0x0001) also known as program in

DVB.

-mpegts_service_type number

Set the program service_type (default digital_tv), see below a list of pre defined values.

-mpegts_pmt_start_pid number

Set the first

PID

for

PMT

(default 0x1000, max 0x1f00).

-mpegts_start_pid number

Set the first

PID

for data packets (default 0x0100, max 0x0f00).

-mpegts_m2ts_mode number

Enable m2ts mode if set to 1. Default value is -1 which disables m2ts mode.

-muxrate number

Set a constant muxrate (default

VBR

).

-pcr_period numer

Override the default

PCR

retransmission time (default 20ms), ignored if variable muxrate is selected.

pat_period number

Maximal time in seconds between

PAT/PMT

tables.

sdt_period number

Maximal time in seconds between

SDT

tables.

-pes_payload_size number

Set minimum

PES

packet payload in bytes.

-mpegts_flags flags

Set flags (see below).

-mpegts_copyts number

Preserve original timestamps, if value is set to 1. Default value is -1, which results in shifting timestamps so that they start from 0.

-tables_version number

Set

PAT, PMT

and

SDT

version (default 0, valid values are from 0 to 31, inclusively). This option allows updating stream structure so that standard consumer may detect the change. To do so, reopen output AVFormatContext (in case of

API

usage) or restart ffmpeg instance, cyclically changing tables_version value:

        ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
        ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
        ...
        ffmpeg -i source3.ts -codec copy -f mpegts -tables_version 31 udp://1.1.1.1:1111
        ffmpeg -i source1.ts -codec copy -f mpegts -tables_version 0 udp://1.1.1.1:1111
        ffmpeg -i source2.ts -codec copy -f mpegts -tables_version 1 udp://1.1.1.1:1111
        ...

Option mpegts_service_type accepts the following values:

hex_value

Any hexdecimal value between 0x01 to 0xff as defined in

ETSI 300 468.

digital_tv

Digital

TV

service.

digital_radio

Digital Radio service.

teletext

Teletext service.

advanced_codec_digital_radio

Advanced Codec Digital Radio service.

mpeg2_digital_hdtv

MPEG2

Digital

HDTV

service.

advanced_codec_digital_sdtv

Advanced Codec Digital

SDTV

service.

advanced_codec_digital_hdtv

Advanced Codec Digital

HDTV

service.

Option mpegts_flags may take a set of such flags:

resend_headers

Reemit

PAT/PMT

before writing the next packet.

latm

Use

LATM

packetization for

AAC.

pat_pmt_at_frames

Reemit

PAT

and

PMT

at each video frame.

Example

        ffmpeg -i file.mpg -c copy \
             -mpegts_original_network_id 0x1122 \
             -mpegts_transport_stream_id 0x3344 \
             -mpegts_service_id 0x5566 \
             -mpegts_pmt_start_pid 0x1500 \
             -mpegts_start_pid 0x150 \
             -metadata service_provider="Some provider" \
             -metadata service_name="Some Channel" \
             -y out.ts

mxf, mxf_d10

Options

The muxer options are:

store_user_comments bool

Set if user comments should be stored if available or never.

IRT D-10

does not allow user comments. The default is thus to write them for mxf but not for mxf_d10

null

This muxer does not generate any output file, it is mainly useful for testing or benchmarking purposes.

For example to benchmark decoding with ffmpeg you can use the command:

        ffmpeg -benchmark -i INPUT -f null out.null

Note that the above command does not read or write the out.null file, but specifying the output file is required by the ffmpeg syntax.

Alternatively you can write the command as:

        ffmpeg -benchmark -i INPUT -f null -

nut

-syncpoints flags

Change the syncpoint usage in nut:

default use the normal low-overhead seeking aids.

none do not use the syncpoints at all, reducing the overhead but making the stream non-seekable;

    Use of this option is not recommended, as the resulting files are very damage
    sensitive and seeking is not possible. Also in general the overhead from
    syncpoints is negligible. Note, -C<write_index> 0 can be used to disable
    all growing data tables, allowing to mux endless streams with limited memory
    and without these disadvantages.

timestamped extend the syncpoint with a wallclock field.

The none and timestamped flags are experimental.

-write_index bool

Write index at the end, the default is to write an index.

        ffmpeg -i INPUT -f_strict experimental -syncpoints none - | processor

ogg

-page_duration duration

Preferred page duration, in microseconds. The muxer will attempt to create pages that are approximately duration microseconds long. This allows the user to compromise between seek granularity and container overhead. The default is 1 second. A value of 0 will fill all segments, making pages as large as possible. A value of 1 will effectively use 1 packet-per-page in most situations, giving a small seek granularity at the cost of additional container overhead.

-serial_offset value

Serial value from which to set the streams serial number. Setting it to different and sufficiently large values ensures that the produced ogg files can be safely chained.

segment, stream_segment, ssegment

This muxer outputs streams to a number of separate files of nearly fixed duration. Output filename pattern can be set in a fashion similar to image2, or by using a "strftime" template if the strftime option is enabled.

"stream_segment" is a variant of the muxer used to write to streaming output formats, i.e. which do not require global headers, and is recommended for outputting e.g. to

Every segment starts with a keyframe of the selected reference stream, which is set through the reference_stream option.

Note that if you want accurate splitting for a video file, you need to make the input key frames correspond to the exact splitting times expected by the segmenter, or the segment muxer will start the new segment with the key frame found next after the specified start time.

The segment muxer works best with a single constant frame rate video.

Optionally it can generate a list of the created segments, by setting the option segment_list. The list type is specified by the segment_list_type option. The entry filenames in the segment list are set by default to the basename of the corresponding segment files.

See also the hls muxer, which provides a more specific implementation for

Options

The segment muxer supports the following options:

reference_stream specifier

Set the reference stream, as specified by the string specifier. If specifier is set to "auto", the reference is chosen automatically. Otherwise it must be a stream specifier (see the ``Stream specifiers'' chapter in the ffmpeg manual) which specifies the reference stream. The default value is "auto".

segment_format format

Override the inner container format, by default it is guessed by the filename extension.

segment_format_options options_list

Set output format options using a :-separated list of key=value parameters. Values containing the ":" special character must be escaped.

segment_list name

Generate also a listfile named name. If not specified no listfile is generated.

segment_list_flags flags

Set flags affecting the segment list generation.

It currently supports the following flags:

cache

Allow caching (only affects M3U8 list files).

live

Allow live-friendly file generation.

segment_list_size size

Update the list file so that it contains at most size segments. If 0 the list file will contain all the segments. Default value is 0.

segment_list_entry_prefix prefix

Prepend prefix to each entry. Useful to generate absolute paths. By default no prefix is applied.

segment_list_type type

Select the listing format.

The following values are recognized:

flat

Generate a flat list for the created segments, one segment per line.

csv, ext

Generate a list for the created segments, one segment per line, each line matching the format (comma-separated values):

        <segment_filename>,<segment_start_time>,<segment_end_time>

segment_filename is the name of the output file generated by the muxer according to the provided pattern.

CSV

escaping (according to

RFC4180

) is applied if required.

segment_start_time and segment_end_time specify the segment start and end time expressed in seconds.

A list file with the suffix ".csv" or ".ext" will auto-select this format.

ext is deprecated in favor or csv.

ffconcat

Generate an ffconcat file for the created segments. The resulting file can be read using the FFmpeg concat demuxer.

A list file with the suffix ".ffcat" or ".ffconcat" will auto-select this format.

m3u8

Generate an extended M3U8 file, version 3, compliant with <tools.ietf.org/id/draft-pantos-http-live-streaming>.

A list file with the suffix ".m3u8" will auto-select this format.

If not specified the type is guessed from the list file name suffix.

segment_time time

Set segment duration to time, the value must be a duration specification. Default value is ``2''. See also the segment_times option.

Note that splitting may not be accurate, unless you force the reference stream key-frames at the given time. See the introductory notice and the examples below.

segment_atclocktime 1|0

If set to ``1'' split at regular clock time intervals starting from 00:00 o'clock. The time value specified in segment_time is used for setting the length of the splitting interval.

For example with segment_time set to ``900'' this makes it possible to create files at 12:00 o'clock, 12:15, 12:30, etc.

Default value is ``0''.

segment_time_delta delta

Specify the accuracy time when selecting the start time for a segment, expressed as a duration specification. Default value is ``0''.

When delta is specified a key-frame will start a new segment if its

PTS

satisfies the relation:

        PTS >= start_time - time_delta

This option is useful when splitting video content, which is always split at

GOP

boundaries, in case a key frame is found just before the specified split time.

In particular may be used in combination with the ffmpeg option force_key_frames. The key frame times specified by force_key_frames may not be set accurately because of rounding issues, with the consequence that a key frame time may result set just before the specified time. For constant frame rate videos a value of 1/(2*frame_rate) should address the worst case mismatch between the specified time and the time set by force_key_frames.

segment_times times

Specify a list of split points. times contains a list of comma separated duration specifications, in increasing order. See also the segment_time option.

segment_frames frames

Specify a list of split video frame numbers. frames contains a list of comma separated integer numbers, in increasing order.

This option specifies to start a new segment whenever a reference stream key frame is found and the sequential number (starting from 0) of the frame is greater or equal to the next value in the list.

segment_wrap limit

Wrap around segment index once it reaches limit.

segment_start_number number

Set the sequence number of the first segment. Defaults to 0.

strftime 1|0

Use the "strftime" function to define the name of the new segments to write. If this is selected, the output segment name must contain a "strftime" function template. Default value is 0.

break_non_keyframes 1|0

If enabled, allow segments to start on frames other than keyframes. This improves behavior on some players when the time between keyframes is inconsistent, but may make things worse on others, and can cause some oddities during seeking. Defaults to 0.

reset_timestamps 1|0

Reset timestamps at the begin of each segment, so that each segment will start with near-zero timestamps. It is meant to ease the playback of the generated segments. May not work with some combinations of muxers/codecs. It is set to 0 by default.

initial_offset offset

Specify timestamp offset to apply to the output packet timestamps. The argument must be a time duration specification, and defaults to 0.

Examples

*

Remux the content of file in.mkv to a list of segments out-000.nut, out-001.nut, etc., and write the list of generated segments to out.list:

        ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.list out%03d.nut

*

Segment input and set output format options for the output segments:

        ffmpeg -i in.mkv -f segment -segment_time 10 -segment_format_options movflags=+faststart out%03d.mp4

*

Segment the input file according to the split points specified by the segment_times option:

        ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 out%03d.nut

*

Use the ffmpeg force_key_frames option to force key frames in the input at the specified location, together with the segment option segment_time_delta to account for possible roundings operated when setting key frame times.

        ffmpeg -i in.mkv -force_key_frames 1,2,3,5,8,13,21 -codec:v mpeg4 -codec:a pcm_s16le -map 0 \
        -f segment -segment_list out.csv -segment_times 1,2,3,5,8,13,21 -segment_time_delta 0.05 out%03d.nut

In order to force key frames on the input file, transcoding is required.

*

Segment the input file by splitting the input file according to the frame numbers sequence specified with the segment_frames option:

        ffmpeg -i in.mkv -codec copy -map 0 -f segment -segment_list out.csv -segment_frames 100,200,300,500,800 out%03d.nut

*

Convert the in.mkv to

TS

segments using the "libx264" and "libfaac" encoders:

        ffmpeg -i in.mkv -map 0 -codec:v libx264 -codec:a libfaac -f ssegment -segment_list out.list out%03d.ts

*

Segment the input file, and create an M3U8 live playlist (can be used as live

HLS

source):

        ffmpeg -re -i in.mkv -codec copy -map 0 -f segment -segment_list playlist.m3u8 \
        -segment_list_flags +live -segment_time 10 out%03d.mkv

smoothstreaming

window_size

Specify the number of fragments kept in the manifest. Default 0 (keep all).

extra_window_size

Specify the number of fragments kept outside of the manifest before removing from disk. Default 5.

lookahead_count

Specify the number of lookahead fragments. Default 2.

min_frag_duration

Specify the minimum fragment duration (in microseconds). Default 5000000.

remove_at_exit

Specify whether to remove all fragments when finished. Default 0 (do not remove).

tee

It is different from specifying several outputs to the ffmpeg command-line tool because the audio and video data will be encoded only once with the tee muxer; encoding can be a very expensive process. It is not useful when using the libavformat

The slave outputs are specified in the file name given to the muxer, separated by '|'. If any of the slave name contains the '|' separator, leading or trailing spaces or any special character, it must be escaped (see the ``Quoting and escaping'' section in the ffmpeg-utils(1) manual).

Muxer options can be specified for each slave by prepending them as a list of key=value pairs separated by ':', between square brackets. If the options values contain a special character or the ':' separator, they must be escaped; note that this is a second level escaping.

The following special options are also recognized:

f

Specify the format name. Useful if it cannot be guessed from the output name suffix.

bsfs[/spec]

Specify a list of bitstream filters to apply to the specified output.

It is possible to specify to which streams a given bitstream filter applies, by appending a stream specifier to the option separated by "/". spec must be a stream specifier (see Format stream specifiers). If the stream specifier is not specified, the bitstream filters will be applied to all streams in the output.

Several bitstream filters can be specified, separated by ``,''.

select

Select the streams that should be mapped to the slave output, specified by a stream specifier. If not specified, this defaults to all the input streams.

Examples

*

Encode something and both archive it in a WebM file and stream it as MPEG-TS over

UDP

(the streams need to be explicitly mapped):

        ffmpeg -i ... -c:v libx264 -c:a mp2 -f tee -map 0:v -map 0:a
          "archive-20121107.mkv|[f=mpegts]udp://10.0.1.255:1234/"

*

Use ffmpeg to encode the input, and send the output to three different destinations. The "dump_extra" bitstream filter is used to add extradata information to all the output video keyframes packets, as requested by the MPEG-TS format. The select option is applied to out.aac in order to make it contain only audio packets.

        ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
               -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=a]out.aac"

*

As below, but select only stream "a:1" for the audio output. Note that a second level escaping must be performed, as ``:'' is a special character used to separate options.

        ffmpeg -i ... -map 0 -flags +global_header -c:v libx264 -c:a aac -strict experimental
               -f tee "[bsfs/v=dump_extra]out.ts|[movflags=+faststart]out.mp4|[select=\'a:1\']out.aac"

Note: some codecs may need different options depending on the output format; the auto-detection of this can not work with the tee muxer. The main example is the global_header flag.

webm_dash_manifest

This muxer implements the WebM

For more information see:

*

WebM

DASH

Specification: <sites.google.com/a/webmproject.org/wiki/adaptive-streaming/webm-dash-specification>

*

ISO DASH

Specification: <standards.iso.org/ittf/PubliclyAvailableStandards/c065274_ISO_IEC_23009-1_2014.zip>

Options

This muxer supports the following options:

adaptation_sets

This option has the following syntax: ``id=x,streams=a,b,c id=y,streams=d,e'' where x and y are the unique identifiers of the adaptation sets and a,b,c,d and e are the indices of the corresponding audio and video streams. Any number of adaptation sets can be added using this option.

live

Set this to 1 to create a live stream

DASH

Manifest. Default: 0.

chunk_start_index

Start index of the first chunk. This will go in the startNumber attribute of the SegmentTemplate element in the manifest. Default: 0.

chunk_duration_ms

Duration of each chunk in milliseconds. This will go in the duration attribute of the SegmentTemplate element in the manifest. Default: 1000.

utc_timing_url

URL

of the page that will return the

UTC

timestamp in

ISO

format. This will go in the value attribute of the UTCTiming element in the manifest. Default: None.

time_shift_buffer_depth

Smallest time (in seconds) shifting buffer for which any Representation is guaranteed to be available. This will go in the timeShiftBufferDepth attribute of the

MPD

element. Default: 60.

minimum_update_period

Minimum update period (in seconds) of the manifest. This will go in the minimumUpdatePeriod attribute of the

MPD

element. Default: 0.

Example

        ffmpeg -f webm_dash_manifest -i video1.webm \
               -f webm_dash_manifest -i video2.webm \
               -f webm_dash_manifest -i audio1.webm \
               -f webm_dash_manifest -i audio2.webm \
               -map 0 -map 1 -map 2 -map 3 \
               -c copy \
               -f webm_dash_manifest \
               -adaptation_sets "id=0,streams=0,1 id=1,streams=2,3" \
               manifest.xml

webm_chunk

This muxer writes out WebM headers and chunks as separate files which can be consumed by clients that support WebM Live streams via

Options

This muxer supports the following options:

chunk_start_index

Index of the first chunk (defaults to 0).

header

Filename of the header where the initialization data will be written.

audio_chunk_duration

Duration of each audio chunk in milliseconds (defaults to 5000).

Example

        ffmpeg -f v4l2 -i /dev/video0 \
               -f alsa -i hw:0 \
               -map 0:0 \
               -c:v libvpx-vp9 \
               -s 640x360 -keyint_min 30 -g 30 \
               -f webm_chunk \
               -header webm_live_video_360.hdr \
               -chunk_start_index 1 \
               webm_live_video_360_%d.chk \
               -map 1:0 \
               -c:a libvorbis \
               -b:a 128k \
               -f webm_chunk \
               -header webm_live_audio_128.hdr \
               -chunk_start_index 1 \
               -audio_chunk_duration 1000 \
               webm_live_audio_128_%d.chk

METADATA

The file format is as follows:

1.

A file consists of a header and a number of metadata tags divided into sections, each on its own line.

2.

The header is a ;FFMETADATA string, followed by a version number (now 1).

3.

Metadata tags are of the form key=value

4.

Immediately after header follows global metadata

5.

After global metadata there may be sections with per-stream/per-chapter metadata.

6.

A section starts with the section name in uppercase (i.e.

STREAM

or

CHAPTER

) in brackets ([, ]) and ends with next section or end of file.

7.

At the beginning of a chapter section there may be an optional timebase to be used for start/end values. It must be in form TIMEBASE=num/den, where num and den are integers. If the timebase is missing then start/end times are assumed to be in milliseconds.

Next a chapter section must contain chapter start and end times in form START=num, END=num, where num is a positive integer.

8.

Empty lines and lines starting with ; or # are ignored.

9.

Metadata keys or values containing special characters (=, ;, #, \ and a newline) must be escaped with a backslash \.

10.

Note that whitespace in metadata (e.g. foo = bar) is considered to be a part of the tag (in the example above key is foo , value is
 bar).

A ffmetadata file might look like this:

        ;FFMETADATA1
        title=bike\\shed
        ;this is a comment
        artist=FFmpeg troll team
        
        [CHAPTER]
        TIMEBASE=1/1000
        START=0
        #chapter ends at 0:01:00
        END=60000
        title=chapter \#1
        [STREAM]
        title=multi\
        line

By using the ffmetadata muxer and demuxer it is possible to extract metadata from an input file to an ffmetadata file, and then transcode the file into an output file with the edited ffmetadata file.

Extracting an ffmetadata file with ffmpeg goes as follows:

        ffmpeg -i INPUT -f ffmetadata FFMETADATAFILE

Reinserting edited metadata information from the

        ffmpeg -i INPUT -i FFMETADATAFILE -map_metadata 1 -codec copy OUTPUT

SEE ALSO

AUTHORS

For details about the authorship, see the Git history of the project (git://source.ffmpeg.org/ffmpeg e.g. by typing the command git log in the FFmpeg source directory, or browsing the online repository at <source.ffmpeg.org>.

Maintainers for the specific components are listed in the file