Utility functions

Miscellaneous utility functions related to both muxing and demuxing (or neither). More...

Modules
	RIFF FourCCs
	Get the tables mapping RIFF FourCCs to libavcodec AVCodecIDs.

Functions
void	av_hex_dump (FILE *f, const uint8_t *buf, int size)
	Send a nice hexadecimal dump of a buffer to the specified file stream. More...
void	av_hex_dump_log (void *avcl, int level, const uint8_t *buf, int size)
	Send a nice hexadecimal dump of a buffer to the log. More...
void	av_pkt_dump2 (FILE *f, const AVPacket *pkt, int dump_payload, const AVStream *st)
	Send a nice dump of a packet to the specified file stream. More...
void	av_pkt_dump_log2 (void *avcl, int level, const AVPacket *pkt, int dump_payload, const AVStream *st)
	Send a nice dump of a packet to the log. More...
enum AVCodecID	av_codec_get_id (const struct AVCodecTag *const *tags, unsigned int tag)
	Get the AVCodecID for the given codec tag tag. More...
unsigned int	av_codec_get_tag (const struct AVCodecTag *const *tags, enum AVCodecID id)
	Get the codec tag for the given codec id id. More...
int	av_codec_get_tag2 (const struct AVCodecTag *const *tags, enum AVCodecID id, unsigned int *tag)
	Get the codec tag for the given codec id. More...
int	av_find_default_stream_index (AVFormatContext *s)
int	av_index_search_timestamp (AVStream *st, int64_t timestamp, int flags)
	Get the index for a specific timestamp. More...
int	av_add_index_entry (AVStream *st, int64_t pos, int64_t timestamp, int size, int distance, int flags)
	Add an index entry into a sorted list. More...
void	av_url_split (char *proto, int proto_size, char *authorization, int authorization_size, char *hostname, int hostname_size, int *port_ptr, char *path, int path_size, const char *url)
	Split a URL string into components. More...
void	av_dump_format (AVFormatContext *ic, int index, const char *url, int is_output)
	Print detailed information about the input or output format, such as duration, bitrate, streams, container, programs, metadata, side data, codec and time base. More...
int	av_get_frame_filename (char *buf, int buf_size, const char *path, int number)
	Return in 'buf' the path with 'd' replaced by a number. More...
int	av_filename_number_test (const char *filename)
	Check whether filename actually is a numbered sequence generator. More...
int	av_sdp_create (AVFormatContext *ac[], int n_files, char *buf, int size)
	Generate an SDP for an RTP session. More...
int	av_match_ext (const char *filename, const char *extensions)
	Return a positive value if the given filename has one of the given extensions, 0 otherwise. More...
int	avformat_query_codec (const AVOutputFormat *ofmt, enum AVCodecID codec_id, int std_compliance)
	Test if the given container can store a codec. More...
AVRational	av_guess_sample_aspect_ratio (AVFormatContext *format, AVStream *stream, AVFrame *frame)
	Guess the sample aspect ratio of a frame, based on both the stream and the frame aspect ratio. More...
AVRational	av_guess_frame_rate (AVFormatContext *ctx, AVStream *stream, AVFrame *frame)
	Guess the frame rate, based on both the container and codec information. More...
int	avformat_match_stream_specifier (AVFormatContext *s, AVStream *st, const char *spec)
	Check if the stream st contained in s is matched by the stream specifier spec. More...
int	avformat_queue_attached_pictures (AVFormatContext *s)

Detailed Description

Miscellaneous utility functions related to both muxing and demuxing (or neither).

Function Documentation

void av_hex_dump	(	FILE *	f,
		const uint8_t *	buf,
		int	size
	)

Send a nice hexadecimal dump of a buffer to the specified file stream.

Parameters

f	The file stream pointer where the dump should be sent to.
buf	buffer
size	buffer size

See Also

av_hex_dump_log, av_pkt_dump2, av_pkt_dump_log2

Definition at line 72 of file dump.c.

Referenced by pkt_dump_internal().

void av_hex_dump_log	(	void *	avcl,
		int	level,
		const uint8_t *	buf,
		int	size
	)

Send a nice hexadecimal dump of a buffer to the log.

Parameters

avcl	A pointer to an arbitrary struct of which the first field is a pointer to an AVClass struct.
level	The importance level of the message, lower values signifying higher importance.
buf	buffer
size	buffer size

See Also

av_hex_dump, av_pkt_dump2, av_pkt_dump_log2

Definition at line 77 of file dump.c.

Referenced by asf_read_header().

void av_pkt_dump2	(	FILE *	f,
		const AVPacket *	pkt,
		int	dump_payload,
		const AVStream *	st
	)

Send a nice dump of a packet to the specified file stream.

Parameters

f	The file stream pointer where the dump should be sent to.
pkt	packet to dump
dump_payload	True if the payload must be displayed, too.
st	AVStream that the packet belongs to

Definition at line 106 of file dump.c.

void av_pkt_dump_log2	(	void *	avcl,
		int	level,
		const AVPacket *	pkt,
		int	dump_payload,
		const AVStream *	st
	)

Send a nice dump of a packet to the log.

Parameters

avcl	A pointer to an arbitrary struct of which the first field is a pointer to an AVClass struct.
level	The importance level of the message, lower values signifying higher importance.
pkt	packet to dump
dump_payload	True if the payload must be displayed, too.
st	AVStream that the packet belongs to

Definition at line 111 of file dump.c.

Referenced by process_input().

enum AVCodecID av_codec_get_id	(	const struct AVCodecTag *const *	tags,
		unsigned int	tag
	)

Get the AVCodecID for the given codec tag tag.

If no codec id is found returns AV_CODEC_ID_NONE.

Parameters

tags	list of supported codec_id-codec_tag pairs, as stored in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
tag	codec tag to match to a codec ID

Referenced by decode_stream_header(), dshow_add_device(), dshow_cycle_formats(), segment_mux_init(), and transcode_init().

unsigned int av_codec_get_tag	(	const struct AVCodecTag *const *	tags,
		enum AVCodecID	id
	)

Get the codec tag for the given codec id id.

If no codec tag is found returns 0.

Parameters

tags	list of supported codec_id-codec_tag pairs, as stored in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
id	codec ID to match to a codec tag

Referenced by init_muxer(), segment_mux_init(), and set_codec_str().

int av_codec_get_tag2	(	const struct AVCodecTag *const *	tags,
		enum AVCodecID	id,
		unsigned int *	tag
	)

Get the codec tag for the given codec id.

Parameters

tags	list of supported codec_id - codec_tag pairs, as stored in AVInputFormat.codec_tag and AVOutputFormat.codec_tag
id	codec id that should be searched for in the list
tag	A pointer to the found tag

Returns

0 if id was not found in tags, > 0 if it was found

Referenced by transcode_init().

int av_find_default_stream_index

(

AVFormatContext *

s

)

Definition at line 1583 of file utils.c.

Referenced by seek_frame_internal(), and update_wrap_reference().

int av_index_search_timestamp	(	AVStream *	st,
		int64_t	timestamp,
		int	flags
	)

Get the index for a specific timestamp.

Parameters

st	stream that the timestamp belongs to
timestamp	timestamp to retrieve the index for
flags	if AVSEEK_FLAG_BACKWARD then the returned index will correspond to the timestamp which is <= the requested one, if backward is 0, then it will be >= if AVSEEK_FLAG_ANY seek to any frame, only keyframes otherwise

Returns

< 0 if no such timestamp could be found

Definition at line 1784 of file utils.c.

Referenced by ape_read_seek(), asf_read_seek(), avi_read_packet(), avi_read_seek(), ff_seek_frame_binary(), gxf_seek(), img_read_seek(), matroska_read_seek(), mov_seek_stream(), mp3_seek(), mpc8_read_seek(), mpc_read_seek(), mv_read_seek(), nsv_read_seek(), nut_write_packet(), read_packet(), read_seek(), rl2_read_seek(), seek_frame_generic(), tta_read_seek(), voc_read_seek(), and webm_clusters_start_with_keyframe().

int av_add_index_entry	(	AVStream *	st,
		int64_t	pos,
		int64_t	timestamp,
		int	size,
		int	distance,
		int	flags
	)

Add an index entry into a sorted list.

Update the entry if the list already contains it.

Parameters

timestamp

timestamp in the time base of the given stream

Definition at line 1742 of file utils.c.

Referenced by ape_read_header(), asf_build_simple_index(), asf_read_pts(), av_read_frame(), avi_read_idx1(), avi_sync(), cine_read_header(), clean_index(), ff_img_read_packet(), ff_voc_get_packet(), find_and_decode_index(), flv_read_packet(), gxf_read_index(), matroska_add_index_entries(), matroska_parse_block(), mov_read_trun(), mpc8_parse_seektable(), mpc_read_packet(), mpegps_read_pes_header(), mpegts_get_dts(), mv_read_header(), nsv_parse_NSVs_header(), nut_write_packet(), nuv_read_dts(), parse_keyframes_index(), pmp_header(), pva_read_header(), read_braindead_odml_indx(), read_frame_internal(), read_header(), read_index(), read_pakt_chunk(), read_part_of_packet(), read_xing_toc(), rl2_read_header(), rm_read_dts(), rm_read_index(), rm_read_packet(), rpl_read_header(), tta_read_header(), and xwma_read_header().

void av_url_split	(	char *	proto,
		int	proto_size,
		char *	authorization,
		int	authorization_size,
		char *	hostname,
		int	hostname_size,
		int *	port_ptr,
		char *	path,
		int	path_size,
		const char *	url
	)

Split a URL string into components.

The pointers to buffers for storing individual components may be null, in order to ignore that component. Buffers for components not found are set to empty strings. If the port is not found, it is set to a negative value.

Parameters

proto	the buffer for the protocol
proto_size	the size of the proto buffer
authorization	the buffer for the authorization
authorization_size	the size of the authorization buffer
hostname	the buffer for the host name
hostname_size	the size of the hostname buffer
port_ptr	a pointer to store the port number in
path	the buffer for the path
path_size	the size of the path buffer
url	the URL to split

Definition at line 3886 of file utils.c.

Referenced by ff_rtp_set_remote_url(), ff_tls_open_underlying(), ff_udp_set_remote_url(), find_rtp_session_with_url(), ftp_open(), gopher_open(), http_listen(), http_open_cnx_internal(), icecast_open(), libssh_open(), mms_open(), mmsh_open_internal(), parse_command_line(), resetup_tcp(), rtmp_http_open(), rtmp_open(), rtmpe_open(), rtp_open(), rtsp_cmd_describe(), rtsp_cmd_setup(), rtsp_listen(), sap_read_header(), sap_write_header(), sctp_open(), srtp_open(), tcp_open(), and udp_open().

void av_dump_format	(	AVFormatContext *	ic,
		int	index,
		const char *	url,
		int	is_output
	)

Print detailed information about the input or output format, such as duration, bitrate, streams, container, programs, metadata, side data, codec and time base.

Parameters

ic	the context to analyze
index	index of the stream to dump information about
url	the URL to print, such as source or destination file
is_output	Select whether the specified context is an input(0) or output(1)

Examples:

avio_reading.c, demuxing_decoding.c, muxing.c, remuxing.c, and transcoding.c.

Definition at line 477 of file dump.c.

Referenced by main(), open_input_file(), open_output_file(), read_thread(), and transcode_init().

int av_get_frame_filename	(	char *	buf,
		int	buf_size,
		const char *	path,
		int	number
	)

Return in 'buf' the path with 'd' replaced by a number.

Also handles the '%0nd' format where 'n' is the total number of digits and '%'.

Parameters

buf	destination buffer
buf_size	destination buffer size
path	numbered sequence string
number	frame number

Returns

0 if OK, -1 on format error

Definition at line 3831 of file utils.c.

Referenced by av_filename_number_test(), ff_img_read_packet(), find_image_range(), get_chunk_filename(), hls_start(), set_segment_filename(), and write_packet().

int av_filename_number_test

(

const char *

filename

)

Check whether filename actually is a numbered sequence generator.

Parameters

filename

possible numbered sequence string

Returns

1 if a valid numbered sequence string, 0 otherwise

Definition at line 258 of file utils.c.

Referenced by av_guess_format(), avformat_open_input(), img_read_probe(), and open_output_file().

int av_sdp_create	(	AVFormatContext *	ac[],
		int	n_files,
		char *	buf,
		int	size
	)

Generate an SDP for an RTP session.

Note, this overwrites the id values of AVStreams in the muxer contexts for getting unique dynamic payload types.

Parameters

ac	array of AVFormatContexts describing the RTP streams. If the array is composed by only one context, such context can contain multiple AVStreams (one AVStream per RTP stream). Otherwise, all the contexts in the array (an AVCodecContext per RTP stream) must contain only one AVStream.
n_files	number of AVCodecContexts contained in ac
buf	buffer where the SDP will be stored (must be allocated by the caller)
size	the size of the buffer

Returns

0 if OK, AVERROR_xxx on error

Definition at line 819 of file sdp.c.

Referenced by ff_rtsp_setup_output_streams(), prepare_sdp_description(), print_sdp(), and sap_write_header().

int av_match_ext	(	const char *	filename,
		const char *	extensions
	)

Return a positive value if the given filename has one of the given extensions, 0 otherwise.

Parameters

filename	file name to check against the given extensions
extensions	a comma-separated list of filename extensions

Definition at line 81 of file format.c.

Referenced by av_guess_format(), av_probe_input_format3(), http_parse_request(), img_read_probe(), ipod_get_codec_tag(), modplug_probe(), mpegts_write_header(), nsv_probe(), and seg_write_header().

int avformat_query_codec	(	const AVOutputFormat *	ofmt,
		enum AVCodecID	codec_id,
		int	std_compliance
	)

Test if the given container can store a codec.

Parameters

ofmt	container to check for compatibility
codec_id	codec to potentially store in container
std_compliance	standards compliance level, one of FF_COMPLIANCE_*

Returns

1 if codec with ID codec_id can be stored in ofmt, 0 if it cannot. A negative number if this information is not available.

Definition at line 4106 of file utils.c.

Referenced by open_output_file().

AVRational av_guess_sample_aspect_ratio	(	AVFormatContext *	format,
		AVStream *	stream,
		AVFrame *	frame
	)

Guess the sample aspect ratio of a frame, based on both the stream and the frame aspect ratio.

Since the frame aspect ratio is set by the codec but the stream aspect ratio is set by the demuxer, these two may not be equal. This function tries to return the value that you should use if you would like to display the frame.

Basic logic is to use the stream aspect ratio if it is set to something sane otherwise use the frame aspect ratio. This way a container setting, which is usually easy to modify can override the coded value in the frames.

Parameters

format	the format context which the stream is part of
stream	the stream which the frame is part of
frame	the frame with the aspect ratio to be determined

Returns

the guessed (valid) sample_aspect_ratio, 0/1 if no idea

Definition at line 4188 of file utils.c.

Referenced by get_video_frame(), read_thread(), show_frame(), and show_stream().

AVRational av_guess_frame_rate	(	AVFormatContext *	ctx,
		AVStream *	stream,
		AVFrame *	frame
	)

Guess the frame rate, based on both the container and codec information.

Parameters

ctx	the format context which the stream is part of
stream	the stream which the frame is part of
frame	the frame for which the frame rate should be determined, may be NULL

Returns

the guessed (valid) frame rate, 0/1 if no idea

Definition at line 4211 of file utils.c.

Referenced by configure_input_video_filter(), and video_thread().

int avformat_match_stream_specifier	(	AVFormatContext *	s,
		AVStream *	st,
		const char *	spec
	)

Check if the stream st contained in s is matched by the stream specifier spec.

See the "stream specifiers" chapter in the documentation for the syntax of spec.

Returns

>0 if st is matched by spec; 0 if st is not matched by spec; AVERROR code if spec is invalid

Note

A stream specifier can match several streams in the format.

Definition at line 4232 of file utils.c.

Referenced by check_stream_specifier(), find_stream(), open_slave(), probe_file(), read_thread(), and select_reference_stream().

int avformat_queue_attached_pictures

(

AVFormatContext *

s

)

Definition at line 379 of file utils.c.

Referenced by av_seek_frame(), avformat_open_input(), avformat_seek_file(), and hls_read_header().