FFMPEG-BITSTREAM-FILTERS(1) FFMPEG-BITSTREAM-FILTERS(1)

NAME
ffmpeg-bitstream-filters - FFmpeg bitstream filters

DESCRIPTION
This document describes the bitstream filters provided by the
libavcodec library.

A bitstream filter operates on the encoded stream data, and performs
bitstream level modifications without performing decoding.

BITSTREAM FILTERS
When you configure your FFmpeg build, all the supported bitstream
filters are enabled by default. You can list all available ones using
the configure option "--list-bsfs".

You can disable all the bitstream filters using the configure option
"--disable-bsfs", and selectively enable any bitstream filter using the
option "--enable-bsf=BSF", or you can disable a particular bitstream
filter using the option "--disable-bsf=BSF".

The option "-bsfs" of the ff* tools will display the list of all the
supported bitstream filters included in your build.

The ff* tools have a -bsf option applied per stream, taking a comma-
separated list of filters, whose parameters follow the filter name
after a '='.

ffmpeg -i INPUT -c:v copy -bsf:v filter1[=opt1=str1:opt2=str2][,filter2] OUTPUT

Below is a description of the currently available bitstream filters,
with their parameters, if any.

aac_adtstoasc
Convert MPEG-2/4 AAC ADTS to an MPEG-4 Audio Specific Configuration
bitstream.

This filter creates an MPEG-4 AudioSpecificConfig from an MPEG-2/4 ADTS
header and removes the ADTS header.

This filter is required for example when copying an AAC stream from a
raw ADTS AAC or an MPEG-TS container to MP4A-LATM, to an FLV file, or
to MOV/MP4 files and related formats such as 3GP or M4A. Please note
that it is auto-inserted for MP4A-LATM and MOV/MP4 and related formats.

av1_metadata
Modify metadata embedded in an AV1 stream.

td Insert or remove temporal delimiter OBUs in all temporal units of
the stream.

insert
Insert a TD at the beginning of every TU which does not already
have one.

remove
Remove the TD from the beginning of every TU which has one.

color_primaries
transfer_characteristics
matrix_coefficients
Set the color description fields in the stream (see AV1 section
6.4.2).

color_range
Set the color range in the stream (see AV1 section 6.4.2; note that
this cannot be set for streams using BT.709 primaries, sRGB
transfer characteristic and identity (RGB) matrix coefficients).

tv Limited range.

pc Full range.

chroma_sample_position
Set the chroma sample location in the stream (see AV1 section
6.4.2). This can only be set for 4:2:0 streams.

vertical
Left position (matching the default in MPEG-2 and H.264).

colocated
Top-left position.

tick_rate
Set the tick rate (num_units_in_display_tick / time_scale) in the
timing info in the sequence header.

num_ticks_per_picture
Set the number of ticks in each picture, to indicate that the
stream has a fixed framerate. Ignored if tick_rate is not also
set.

chomp
Remove zero padding at the end of a packet.

dca_core
Extract the core from a DCA/DTS stream, dropping extensions such as
DTS-HD.

dump_extra
Add extradata to the beginning of the filtered packets.

freq
The additional argument specifies which packets should be filtered.
It accepts the values:

k
keyframe
add extradata to all key packets

e
all add extradata to all packets

If not specified it is assumed e.

For example the following ffmpeg command forces a global header (thus
disabling individual packet headers) in the H.264 packets generated by
the "libx264" encoder, but corrects them by adding the header stored in
extradata to the key packets:

ffmpeg -i INPUT -map 0 -flags:v +global_header -c:v libx264 -bsf:v dump_extra out.ts

eac3_core
Extract the core from a E-AC-3 stream, dropping extra channels.

extract_extradata
Extract the in-band extradata.

Certain codecs allow the long-term headers (e.g. MPEG-2 sequence
headers, or H.264/HEVC (VPS/)SPS/PPS) to be transmitted either "in-
band" (i.e. as a part of the bitstream containing the coded frames) or
"out of band" (e.g. on the container level). This latter form is called
"extradata" in FFmpeg terminology.

This bitstream filter detects the in-band headers and makes them
available as extradata.

remove
When this option is enabled, the long-term headers are removed from
the bitstream after extraction.

filter_units
Remove units with types in or not in a given set from the stream.

pass_types
List of unit types or ranges of unit types to pass through while
removing all others. This is specified as a '|'-separated list of
unit type values or ranges of values with '-'.

remove_types
Identical to pass_types, except the units in the given set removed
and all others passed through.

Extradata is unchanged by this transformation, but note that if the
stream contains inline parameter sets then the output may be unusable
if they are removed.

For example, to remove all non-VCL NAL units from an H.264 stream:

ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=pass_types=1-5' OUTPUT

To remove all AUDs, SEI and filler from an H.265 stream:

ffmpeg -i INPUT -c:v copy -bsf:v 'filter_units=remove_types=35|38-40' OUTPUT

hapqa_extract
Extract Rgb or Alpha part of an HAPQA file, without recompression, in
order to create an HAPQ or an HAPAlphaOnly file.

texture
Specifies the texture to keep.

color
alpha

Convert HAPQA to HAPQ

ffmpeg -i hapqa_inputfile.mov -c copy -bsf:v hapqa_extract=texture=color -tag:v HapY -metadata:s:v:0 encoder="HAPQ" hapq_file.mov

Convert HAPQA to HAPAlphaOnly

ffmpeg -i hapqa_inputfile.mov -c copy -bsf:v hapqa_extract=texture=alpha -tag:v HapA -metadata:s:v:0 encoder="HAPAlpha Only" hapalphaonly_file.mov

h264_metadata
Modify metadata embedded in an H.264 stream.

aud Insert or remove AUD NAL units in all access units of the stream.

insert
remove
sample_aspect_ratio
Set the sample aspect ratio of the stream in the VUI parameters.

video_format
video_full_range_flag
Set the video format in the stream (see H.264 section E.2.1 and
table E-2).

colour_primaries
transfer_characteristics
matrix_coefficients
Set the colour description in the stream (see H.264 section E.2.1
and tables E-3, E-4 and E-5).

chroma_sample_loc_type
Set the chroma sample location in the stream (see H.264 section
E.2.1 and figure E-1).

tick_rate
Set the tick rate (num_units_in_tick / time_scale) in the VUI
parameters. This is the smallest time unit representable in the
stream, and in many cases represents the field rate of the stream
(double the frame rate).

fixed_frame_rate_flag
Set whether the stream has fixed framerate - typically this
indicates that the framerate is exactly half the tick rate, but the
exact meaning is dependent on interlacing and the picture structure
(see H.264 section E.2.1 and table E-6).

crop_left
crop_right
crop_top
crop_bottom
Set the frame cropping offsets in the SPS. These values will
replace the current ones if the stream is already cropped.

These fields are set in pixels. Note that some sizes may not be
representable if the chroma is subsampled or the stream is
interlaced (see H.264 section 7.4.2.1.1).

sei_user_data
Insert a string as SEI unregistered user data. The argument must
be of the form UUID+string, where the UUID is as hex digits
possibly separated by hyphens, and the string can be anything.

For example, 086f3693-b7b3-4f2c-9653-21492feee5b8+hello will insert
the string ``hello'' associated with the given UUID.

delete_filler
Deletes both filler NAL units and filler SEI messages.

level
Set the level in the SPS. Refer to H.264 section A.3 and tables
A-1 to A-5.

The argument must be the name of a level (for example, 4.2), a
level_idc value (for example, 42), or the special name auto
indicating that the filter should attempt to guess the level from
the input stream properties.

h264_mp4toannexb
Convert an H.264 bitstream from length prefixed mode to start code
prefixed mode (as defined in the Annex B of the ITU-T H.264
specification).

This is required by some streaming formats, typically the MPEG-2
transport stream format (muxer "mpegts").

For example to remux an MP4 file containing an H.264 stream to mpegts
format with ffmpeg, you can use the command:

ffmpeg -i INPUT.mp4 -codec copy -bsf:v h264_mp4toannexb OUTPUT.ts

Please note that this filter is auto-inserted for MPEG-TS (muxer
"mpegts") and raw H.264 (muxer "h264") output formats.

h264_redundant_pps
This applies a specific fixup to some Blu-ray streams which contain
redundant PPSs modifying irrelevant parameters of the stream which
confuse other transformations which require correct extradata.

A new single global PPS is created, and all of the redundant PPSs
within the stream are removed.

hevc_metadata
Modify metadata embedded in an HEVC stream.

aud Insert or remove AUD NAL units in all access units of the stream.

insert
remove
sample_aspect_ratio
Set the sample aspect ratio in the stream in the VUI parameters.

video_format
video_full_range_flag
Set the video format in the stream (see H.265 section E.3.1 and
table E.2).

colour_primaries
transfer_characteristics
matrix_coefficients
Set the colour description in the stream (see H.265 section E.3.1
and tables E.3, E.4 and E.5).

chroma_sample_loc_type
Set the chroma sample location in the stream (see H.265 section
E.3.1 and figure E.1).

tick_rate
Set the tick rate in the VPS and VUI parameters (num_units_in_tick
/ time_scale). Combined with num_ticks_poc_diff_one, this can set
a constant framerate in the stream. Note that it is likely to be
overridden by container parameters when the stream is in a
container.

num_ticks_poc_diff_one
Set poc_proportional_to_timing_flag in VPS and VUI and use this
value to set num_ticks_poc_diff_one_minus1 (see H.265 sections
7.4.3.1 and E.3.1). Ignored if tick_rate is not also set.

crop_left
crop_right
crop_top
crop_bottom
Set the conformance window cropping offsets in the SPS. These
values will replace the current ones if the stream is already
cropped.

These fields are set in pixels. Note that some sizes may not be
representable if the chroma is subsampled (H.265 section
7.4.3.2.1).

hevc_mp4toannexb
Convert an HEVC/H.265 bitstream from length prefixed mode to start code
prefixed mode (as defined in the Annex B of the ITU-T H.265
specification).

This is required by some streaming formats, typically the MPEG-2
transport stream format (muxer "mpegts").

For example to remux an MP4 file containing an HEVC stream to mpegts
format with ffmpeg, you can use the command:

ffmpeg -i INPUT.mp4 -codec copy -bsf:v hevc_mp4toannexb OUTPUT.ts

Please note that this filter is auto-inserted for MPEG-TS (muxer
"mpegts") and raw HEVC/H.265 (muxer "h265" or "hevc") output formats.

imxdump
Modifies the bitstream to fit in MOV and to be usable by the Final Cut
Pro decoder. This filter only applies to the mpeg2video codec, and is
likely not needed for Final Cut Pro 7 and newer with the appropriate
-tag:v.

For example, to remux 30 MB/sec NTSC IMX to MOV:

ffmpeg -i input.mxf -c copy -bsf:v imxdump -tag:v mx3n output.mov

mjpeg2jpeg
Convert MJPEG/AVI1 packets to full JPEG/JFIF packets.

MJPEG is a video codec wherein each video frame is essentially a JPEG
image. The individual frames can be extracted without loss, e.g. by

ffmpeg -i ../some_mjpeg.avi -c:v copy frames_%d.jpg

Unfortunately, these chunks are incomplete JPEG images, because they
lack the DHT segment required for decoding. Quoting from
<http://www.digitalpreservation.gov/formats/fdd/fdd000063.shtml>:

Avery Lee, writing in the rec.video.desktop newsgroup in 2001,
commented that "MJPEG, or at least the MJPEG in AVIs having the MJPG
fourcc, is restricted JPEG with a fixed -- and *omitted* -- Huffman
table. The JPEG must be YCbCr colorspace, it must be 4:2:2, and it must
use basic Huffman encoding, not arithmetic or progressive. . . . You
can indeed extract the MJPEG frames and decode them with a regular JPEG
decoder, but you have to prepend the DHT segment to them, or else the
decoder won't have any idea how to decompress the data. The exact table
necessary is given in the OpenDML spec."

This bitstream filter patches the header of frames extracted from an
MJPEG stream (carrying the AVI1 header ID and lacking a DHT segment) to
produce fully qualified JPEG images.

ffmpeg -i mjpeg-movie.avi -c:v copy -bsf:v mjpeg2jpeg frame_%d.jpg
exiftran -i -9 frame*.jpg
ffmpeg -i frame_%d.jpg -c:v copy rotated.avi

mjpegadump
Add an MJPEG A header to the bitstream, to enable decoding by
Quicktime.

mov2textsub
Extract a representable text file from MOV subtitles, stripping the
metadata header from each subtitle packet.