#include "config.h"
#include "config_components.h"
#include <stdint.h>
#include <time.h>
#include "libavutil/avassert.h"
#include "libavutil/mathematics.h"
#include "libavutil/avstring.h"
#include "libavutil/bprint.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/log.h"
#include "libavutil/random_seed.h"
#include "libavutil/time_internal.h"
#include "libavcodec/defs.h"
#include "avformat.h"
#include "avio_internal.h"
#include "avc.h"
#include "hlsplaylist.h"
#include "internal.h"
#include "mux.h"
#include "os_support.h"
#include "url.h"

Data Structures
struct	HLSSegment

struct	VariantStream

struct	ClosedCaptionsStream

struct	HLSContext

Macros
#define	KEYSIZE 16

#define	LINE_BUFFER_SIZE MAX_URL_SIZE

#define	HLS_MICROSECOND_UNIT 1000000

#define	BUFSIZE (16 * 1024)

#define	POSTFIX_PATTERN "_%d"

#define	SEPARATOR '/'

#define	OFFSET(x) offsetof(HLSContext, x)

#define	E AV_OPT_FLAG_ENCODING_PARAM

Enumerations
enum	StartSequenceSourceType { HLS_START_SEQUENCE_AS_START_NUMBER = 0, HLS_START_SEQUENCE_AS_SECONDS_SINCE_EPOCH = 1, HLS_START_SEQUENCE_AS_FORMATTED_DATETIME = 2, HLS_START_SEQUENCE_AS_MICROSECONDS_SINCE_EPOCH = 3, HLS_START_SEQUENCE_LAST }

enum	CodecAttributeStatus { CODEC_ATTRIBUTE_WRITTEN = 0, CODEC_ATTRIBUTE_WILL_NOT_BE_WRITTEN }

enum	HLSFlags { HLS_SINGLE_FILE = (1 << 0), HLS_DELETE_SEGMENTS = (1 << 1), HLS_ROUND_DURATIONS = (1 << 2), HLS_DISCONT_START = (1 << 3), HLS_OMIT_ENDLIST = (1 << 4), HLS_SPLIT_BY_TIME = (1 << 5), HLS_APPEND_LIST = (1 << 6), HLS_PROGRAM_DATE_TIME = (1 << 7), HLS_SECOND_LEVEL_SEGMENT_INDEX = (1 << 8), HLS_SECOND_LEVEL_SEGMENT_DURATION = (1 << 9), HLS_SECOND_LEVEL_SEGMENT_SIZE = (1 << 10), HLS_TEMP_FILE = (1 << 11), HLS_PERIODIC_REKEY = (1 << 12), HLS_INDEPENDENT_SEGMENTS = (1 << 13), HLS_I_FRAMES_ONLY = (1 << 14) }

enum	SegmentType { PALETTE_SEGMENT = 0x14, OBJECT_SEGMENT = 0x15, PRESENTATION_SEGMENT = 0x16, WINDOW_SEGMENT = 0x17, DISPLAY_SEGMENT = 0x80, SEGMENT_TYPE_AUTO = 0, SEGMENT_TYPE_MP4, SEGMENT_TYPE_WEBM, SEGMENT_TYPE_NB, SEGMENT_TYPE_MPEGTS, SEGMENT_TYPE_FMP4 }

Functions
static int	strftime_expand (const char fmt, char *dest)

static int	hlsenc_io_open (AVFormatContext s, AVIOContext pb, const char filename, AVDictionary **options)

static int	hlsenc_io_close (AVFormatContext s, AVIOContext pb, char filename)

static void	set_http_options (AVFormatContext s, AVDictionary options, HLSContext c)

static void	write_codec_attr (AVStream st, VariantStream vs)

static int	replace_str_data_in_filename (char *s, const char filename, char placeholder, const char *datastring)

static int	replace_int_data_in_filename (char *s, const char filename, char placeholder, int64_t number)

static void	write_styp (AVIOContext *pb)

static int	flush_dynbuf (VariantStream vs, int range_length)

static void	reflush_dynbuf (VariantStream vs, int range_length)

static int	hls_delete_file (HLSContext hls, AVFormatContext avf, char path, const char proto)

static int	hls_delete_old_segments (AVFormatContext s, HLSContext hls, VariantStream *vs)

static int	do_encrypt (AVFormatContext s, VariantStream vs)

static int	hls_encryption_start (AVFormatContext s, VariantStream vs)

static int	hls_mux_init (AVFormatContext s, VariantStream vs)

static HLSSegment *	find_segment_by_filename (HLSSegment segment, const char filename)

static int	sls_flags_filename_process (struct AVFormatContext s, HLSContext hls, VariantStream vs, HLSSegment en, double duration, int64_t pos, int64_t size)

static int	sls_flag_check_duration_size_index (HLSContext *hls)

static int	sls_flag_check_duration_size (HLSContext hls, VariantStream vs)

static void	sls_flag_file_rename (HLSContext hls, VariantStream vs, char *old_filename)

static int	sls_flag_use_localtime_filename (AVFormatContext oc, HLSContext c, VariantStream *vs)

static int	hls_append_segment (struct AVFormatContext s, HLSContext hls, VariantStream *vs, double duration, int64_t pos, int64_t size)

static int	parse_playlist (AVFormatContext s, const char url, VariantStream *vs)

static void	hls_free_segments (HLSSegment *p)

static int	hls_rename_temp_file (AVFormatContext s, AVFormatContext oc)

static const char *	get_relative_url (const char master_url, const char media_url)

static int64_t	get_stream_bit_rate (AVStream *stream)

static int	create_master_playlist (AVFormatContext s, VariantStream const input_vs)

static int	hls_window (AVFormatContext s, int last, VariantStream vs)

static int	hls_start (AVFormatContext s, VariantStream vs)

static const char *	get_default_pattern_localtime_fmt (AVFormatContext *s)

static int	append_postfix (char *name, int name_buf_len, int i)

static int	validate_name (int nb_vs, const char *fn)

static int	format_name (const char buf, char s, int index, const char varname)

static int	get_nth_codec_stream_index (AVFormatContext *s, enum AVMediaType codec_type, int64_t stream_id)

static int	parse_variant_stream_mapstring (AVFormatContext *s)

static int	parse_cc_stream_mapstring (AVFormatContext *s)

static int	update_variant_stream_info (AVFormatContext *s)

static int	update_master_pl_info (AVFormatContext *s)

static int	hls_write_header (AVFormatContext *s)

static int	hls_init_file_resend (AVFormatContext s, VariantStream vs)

static int64_t	append_single_file (AVFormatContext s, VariantStream vs)

static int	hls_write_packet (AVFormatContext s, AVPacket pkt)

static void	hls_deinit (AVFormatContext *s)

static int	hls_write_trailer (struct AVFormatContext *s)

static int	hls_init (AVFormatContext *s)

Variables
static const AVOption	options []

static const AVClass	hls_class

const FFOutputFormat	ff_hls_muxer

Macro Definition Documentation

◆ KEYSIZE

#define KEYSIZE 16

Definition at line 69 of file hlsenc.c.

◆ LINE_BUFFER_SIZE

#define LINE_BUFFER_SIZE MAX_URL_SIZE

Definition at line 70 of file hlsenc.c.

◆ HLS_MICROSECOND_UNIT

#define HLS_MICROSECOND_UNIT 1000000

Definition at line 71 of file hlsenc.c.

◆ BUFSIZE

#define BUFSIZE (16 * 1024)

Definition at line 72 of file hlsenc.c.

◆ POSTFIX_PATTERN

#define POSTFIX_PATTERN "_%d"

Definition at line 73 of file hlsenc.c.

◆ SEPARATOR

#define SEPARATOR '/'

Definition at line 575 of file hlsenc.c.

◆ OFFSET

#define OFFSET ( x ) offsetof(HLSContext, x)

Definition at line 3128 of file hlsenc.c.

◆ E

#define E AV_OPT_FLAG_ENCODING_PARAM

Definition at line 3129 of file hlsenc.c.

Enumeration Type Documentation

◆ StartSequenceSourceType

enum StartSequenceSourceType

Enumerator
HLS_START_SEQUENCE_AS_START_NUMBER
HLS_START_SEQUENCE_AS_SECONDS_SINCE_EPOCH
HLS_START_SEQUENCE_AS_FORMATTED_DATETIME
HLS_START_SEQUENCE_AS_MICROSECONDS_SINCE_EPOCH
HLS_START_SEQUENCE_LAST

Definition at line 56 of file hlsenc.c.

◆ CodecAttributeStatus

enum CodecAttributeStatus

Enumerator
CODEC_ATTRIBUTE_WRITTEN
CODEC_ATTRIBUTE_WILL_NOT_BE_WRITTEN

Definition at line 64 of file hlsenc.c.

◆ HLSFlags

enum HLSFlags

Enumerator
HLS_SINGLE_FILE
HLS_DELETE_SEGMENTS
HLS_ROUND_DURATIONS
HLS_DISCONT_START
HLS_OMIT_ENDLIST
HLS_SPLIT_BY_TIME
HLS_APPEND_LIST
HLS_PROGRAM_DATE_TIME
HLS_SECOND_LEVEL_SEGMENT_INDEX
HLS_SECOND_LEVEL_SEGMENT_DURATION
HLS_SECOND_LEVEL_SEGMENT_SIZE
HLS_TEMP_FILE
HLS_PERIODIC_REKEY
HLS_INDEPENDENT_SEGMENTS
HLS_I_FRAMES_ONLY

Definition at line 93 of file hlsenc.c.

◆ SegmentType

enum SegmentType

Enumerator
PALETTE_SEGMENT
OBJECT_SEGMENT
PRESENTATION_SEGMENT
WINDOW_SEGMENT
DISPLAY_SEGMENT
SEGMENT_TYPE_AUTO
SEGMENT_TYPE_MP4
SEGMENT_TYPE_WEBM
SEGMENT_TYPE_NB
SEGMENT_TYPE_MPEGTS
SEGMENT_TYPE_FMP4

Definition at line 112 of file hlsenc.c.

Function Documentation

◆ strftime_expand()

static int strftime_expand	(	const char *	fmt,
		char **	dest
	)

static

Definition at line 260 of file hlsenc.c.

Referenced by hls_init(), and hls_start().

◆ hlsenc_io_open()

static int hlsenc_io_open	(	AVFormatContext *	s,
		AVIOContext **	pb,
		const char *	filename,
		AVDictionary **	options
	)

static

Definition at line 283 of file hlsenc.c.

Referenced by create_master_playlist(), hls_delete_file(), hls_init_file_resend(), hls_mux_init(), hls_start(), hls_window(), hls_write_packet(), and hls_write_trailer().

◆ hlsenc_io_close()

static int hlsenc_io_close	(	AVFormatContext *	s,
		AVIOContext **	pb,
		char *	filename
	)

static

Definition at line 304 of file hlsenc.c.

Referenced by append_single_file(), create_master_playlist(), hls_delete_file(), hls_init_file_resend(), hls_window(), hls_write_packet(), and hls_write_trailer().

◆ set_http_options()

static void set_http_options	(	AVFormatContext *	s,
		AVDictionary **	options,
		HLSContext *	c
	)

static

Definition at line 324 of file hlsenc.c.

Referenced by create_master_playlist(), do_encrypt(), hls_delete_file(), hls_encryption_start(), hls_init_file_resend(), hls_mux_init(), hls_start(), hls_window(), hls_write_packet(), and hls_write_trailer().

◆ write_codec_attr()

static void write_codec_attr	(	AVStream *	st,
		VariantStream *	vs
	)

static

Definition at line 343 of file hlsenc.c.

Referenced by hls_write_header().

◆ replace_str_data_in_filename()

static int replace_str_data_in_filename	(	char **	s,
		const char *	filename,
		char	placeholder,
		const char *	datastring
	)

static

Definition at line 447 of file hlsenc.c.

Referenced by format_name(), and hls_delete_old_segments().

◆ replace_int_data_in_filename()

static int replace_int_data_in_filename	(	char **	s,
		const char *	filename,
		char	placeholder,
		int64_t	number
	)

static

Definition at line 487 of file hlsenc.c.

Referenced by format_name(), hls_delete_old_segments(), hls_start(), sls_flag_use_localtime_filename(), and sls_flags_filename_process().

◆ write_styp()

static void write_styp ( AVIOContext * pb )

static

Definition at line 535 of file hlsenc.c.

Referenced by hls_write_packet(), and hls_write_trailer().

◆ flush_dynbuf()

static int flush_dynbuf	(	VariantStream *	vs,
		int *	range_length
	)

static

Definition at line 545 of file hlsenc.c.

Referenced by hls_write_packet(), and hls_write_trailer().

◆ reflush_dynbuf()

static void reflush_dynbuf	(	VariantStream *	vs,
		int *	range_length
	)

static

Definition at line 566 of file hlsenc.c.

Referenced by hls_write_packet(), and hls_write_trailer().

◆ hls_delete_file()

static int hls_delete_file	(	HLSContext *	hls,
		AVFormatContext *	avf,
		char *	path,
		const char *	proto
	)

static

Definition at line 578 of file hlsenc.c.

Referenced by hls_delete_old_segments().

◆ hls_delete_old_segments()

static int hls_delete_old_segments	(	AVFormatContext *	s,
		HLSContext *	hls,
		VariantStream *	vs
	)

static

Definition at line 602 of file hlsenc.c.

Referenced by hls_append_segment().

◆ do_encrypt()

static int do_encrypt	(	AVFormatContext *	s,
		VariantStream *	vs
	)

static

Definition at line 713 of file hlsenc.c.

Referenced by hls_start().

◆ hls_encryption_start()

static int hls_encryption_start	(	AVFormatContext *	s,
		VariantStream *	vs
	)

static

Definition at line 786 of file hlsenc.c.

Referenced by hls_start().

◆ hls_mux_init()

static int hls_mux_init	(	AVFormatContext *	s,
		VariantStream *	vs
	)

static

Definition at line 845 of file hlsenc.c.

Referenced by hls_init().

◆ find_segment_by_filename()

static HLSSegment* find_segment_by_filename	(	HLSSegment *	segment,
		const char *	filename
	)

static

Definition at line 960 of file hlsenc.c.

Referenced by hls_append_segment().

◆ sls_flags_filename_process()

static int sls_flags_filename_process	(	struct AVFormatContext *	s,
		HLSContext *	hls,
		VariantStream *	vs,
		HLSSegment *	en,
		double	duration,
		int64_t	pos,
		int64_t	size
	)

static

Definition at line 970 of file hlsenc.c.

Referenced by hls_append_segment().

◆ sls_flag_check_duration_size_index()

static int sls_flag_check_duration_size_index ( HLSContext * hls )

static

Definition at line 1010 of file hlsenc.c.

Referenced by hls_init().

◆ sls_flag_check_duration_size()

static int sls_flag_check_duration_size	(	HLSContext *	hls,
		VariantStream *	vs
	)

static

Definition at line 1033 of file hlsenc.c.

Referenced by hls_init().

◆ sls_flag_file_rename()

static void sls_flag_file_rename	(	HLSContext *	hls,
		VariantStream *	vs,
		char *	old_filename
	)

static

Definition at line 1053 of file hlsenc.c.

Referenced by hls_write_packet(), and hls_write_trailer().

◆ sls_flag_use_localtime_filename()

static int sls_flag_use_localtime_filename	(	AVFormatContext *	oc,
		HLSContext *	c,
		VariantStream *	vs
	)

static

Definition at line 1060 of file hlsenc.c.

Referenced by hls_start().

◆ hls_append_segment()

static int hls_append_segment	(	struct AVFormatContext *	s,
		HLSContext *	hls,
		VariantStream *	vs,
		double	duration,
		int64_t	pos,
		int64_t	size
	)

static

Definition at line 1104 of file hlsenc.c.

Referenced by hls_write_packet(), hls_write_trailer(), and parse_playlist().

◆ parse_playlist()

static int parse_playlist	(	AVFormatContext *	s,
		const char *	url,
		VariantStream *	vs
	)

static

Definition at line 1193 of file hlsenc.c.

Referenced by hls_init().

◆ hls_free_segments()

static void hls_free_segments ( HLSSegment * p )

static

Definition at line 1306 of file hlsenc.c.

Referenced by hls_deinit().

◆ hls_rename_temp_file()

static int hls_rename_temp_file	(	AVFormatContext *	s,
		AVFormatContext *	oc
	)

static

Definition at line 1317 of file hlsenc.c.

Referenced by hls_write_packet(), and hls_write_trailer().

◆ get_relative_url()

static const char* get_relative_url	(	const char *	master_url,
		const char *	media_url
	)

static

Definition at line 1332 of file hlsenc.c.

Referenced by create_master_playlist().

◆ get_stream_bit_rate()

static int64_t get_stream_bit_rate ( AVStream * stream )

static

Definition at line 1352 of file hlsenc.c.

Referenced by create_master_playlist().

◆ create_master_playlist()

static int create_master_playlist	(	AVFormatContext *	s,
		VariantStream *const	input_vs
	)

static

Traverse through the list of audio only rendition streams and find the rendition which has highest bitrate in the same audio group

Definition at line 1369 of file hlsenc.c.

Referenced by hls_window().

◆ hls_window()

static int hls_window	(	AVFormatContext *	s,
		int	last,
		VariantStream *	vs
	)

static

Definition at line 1541 of file hlsenc.c.

Referenced by hls_write_packet(), and hls_write_trailer().

◆ hls_start()

static int hls_start	(	AVFormatContext *	s,
		VariantStream *	vs
	)

static

Definition at line 1689 of file hlsenc.c.

Referenced by hls_init(), and hls_write_packet().

◆ get_default_pattern_localtime_fmt()

static const char* get_default_pattern_localtime_fmt ( AVFormatContext * s )

static

Definition at line 1874 of file hlsenc.c.

Referenced by hls_init().

◆ append_postfix()

static int append_postfix	(	char *	name,
		int	name_buf_len,
		int	i
	)

static

Definition at line 1895 of file hlsenc.c.

Referenced by hls_init().

◆ validate_name()

static int validate_name	(	int	nb_vs,
		const char *	fn
	)

static

Definition at line 1914 of file hlsenc.c.

Referenced by hls_init().

◆ format_name()

static int format_name	(	const char *	buf,
		char **	s,
		int	index,
		const char *	varname
	)

static

Definition at line 1948 of file hlsenc.c.

Referenced by hls_init().

◆ get_nth_codec_stream_index()

static int get_nth_codec_stream_index	(	AVFormatContext *	s,
		enum AVMediaType	codec_type,
		int64_t	stream_id
	)

static

Definition at line 1994 of file hlsenc.c.

Referenced by parse_variant_stream_mapstring().

◆ parse_variant_stream_mapstring()

static int parse_variant_stream_mapstring ( AVFormatContext * s )

static

Expected format for var_stream_map string is as below: "a:0,v:0 a:1,v:1" "a:0,agroup:a0,default:1,language:ENG a:1,agroup:a1,default:0 v:0,agroup:a0 v:1,agroup:a1" This string specifies how to group the audio, video and subtitle streams into different variant streams. The variant stream groups are separated by space.

a:, v:, s: are keys to specify audio, video and subtitle streams respectively. Allowed values are 0 to 9 digits (limited just based on practical usage)

agroup: is key to specify audio group. A string can be given as value. sgroup: is key to specify subtitle group. A string can be given as value.

Definition at line 2012 of file hlsenc.c.

Referenced by update_variant_stream_info().

◆ parse_cc_stream_mapstring()

static int parse_cc_stream_mapstring ( AVFormatContext * s )

static

Definition at line 2155 of file hlsenc.c.

Referenced by update_variant_stream_info().

◆ update_variant_stream_info()

static int update_variant_stream_info ( AVFormatContext * s )

static

Definition at line 2232 of file hlsenc.c.

Referenced by hls_init().

◆ update_master_pl_info()

static int update_master_pl_info ( AVFormatContext * s )

static

if output file's directory has v, variants are created in sub-directories then master is created at the sub-directories level

Definition at line 2270 of file hlsenc.c.

Referenced by hls_init().

◆ hls_write_header()

static int hls_write_header ( AVFormatContext * s )

static

Definition at line 2312 of file hlsenc.c.

◆ hls_init_file_resend()

static int hls_init_file_resend	(	AVFormatContext *	s,
		VariantStream *	vs
	)

static

Definition at line 2373 of file hlsenc.c.

Referenced by hls_write_packet().

◆ append_single_file()

static int64_t append_single_file	(	AVFormatContext *	s,
		VariantStream *	vs
	)

static

Definition at line 2390 of file hlsenc.c.

Referenced by hls_write_packet(), and hls_write_trailer().

◆ hls_write_packet()

static int hls_write_packet	(	AVFormatContext *	s,
		AVPacket *	pkt
	)

static

Definition at line 2421 of file hlsenc.c.

◆ hls_deinit()

static void hls_deinit ( AVFormatContext * s )

static

Definition at line 2704 of file hlsenc.c.

◆ hls_write_trailer()

static int hls_write_trailer ( struct AVFormatContext * s )

static

Definition at line 2738 of file hlsenc.c.

◆ hls_init()

static int hls_init ( AVFormatContext * s )

static

Definition at line 2877 of file hlsenc.c.

Variable Documentation

◆ options

const AVOption options[]

static

Definition at line 3130 of file hlsenc.c.

Referenced by create_master_playlist(), do_encrypt(), hls_encryption_start(), hls_init_file_resend(), hls_mux_init(), hls_start(), hls_window(), hls_write_packet(), hls_write_trailer(), hlsenc_io_open(), and set_http_options().

◆ hls_class

const AVClass hls_class

static

Initial value:

= {
    .class_name = "hls muxer",
    .item_name  = av_default_item_name,
    .option     = options,
    .version    = LIBAVUTIL_VERSION_INT,
}

Definition at line 3192 of file hlsenc.c.

◆ ff_hls_muxer

const FFOutputFormat ff_hls_muxer

Initial value:

= {
    .p.name           = "hls",
    .p.long_name      = NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming"),
    .p.extensions     = "m3u8",
    .p.audio_codec    = AV_CODEC_ID_AAC,
    .p.video_codec    = AV_CODEC_ID_H264,
    .p.subtitle_codec = AV_CODEC_ID_WEBVTT,
 
 
 
    .p.flags          = AVFMT_NOFILE | AVFMT_GLOBALHEADER | AVFMT_NODIMENSIONS,
 
    .p.priv_class     = &hls_class,
    .flags_internal   = FF_OFMT_FLAG_ALLOW_FLUSH,
    .priv_data_size = sizeof(HLSContext),
    .init           = hls_init,
    .write_header   = hls_write_header,
    .write_packet   = hls_write_packet,
    .write_trailer  = hls_write_trailer,
    .deinit         = hls_deinit,
}

Definition at line 3200 of file hlsenc.c.

Data Structures

Macros

Enumerations

Functions

Variables

Macro Definition Documentation

◆ KEYSIZE

◆ LINE_BUFFER_SIZE

◆ HLS_MICROSECOND_UNIT

◆ BUFSIZE

◆ POSTFIX_PATTERN

◆ SEPARATOR

◆ OFFSET

◆ E

Enumeration Type Documentation

◆ StartSequenceSourceType

◆ CodecAttributeStatus

◆ HLSFlags

◆ SegmentType

Function Documentation

◆ strftime_expand()

◆ hlsenc_io_open()

◆ hlsenc_io_close()

◆ set_http_options()

◆ write_codec_attr()

◆ replace_str_data_in_filename()

◆ replace_int_data_in_filename()

◆ write_styp()

◆ flush_dynbuf()

◆ reflush_dynbuf()

◆ hls_delete_file()

◆ hls_delete_old_segments()

◆ do_encrypt()

◆ hls_encryption_start()

◆ hls_mux_init()

◆ find_segment_by_filename()

◆ sls_flags_filename_process()

◆ sls_flag_check_duration_size_index()

◆ sls_flag_check_duration_size()

◆ sls_flag_file_rename()

◆ sls_flag_use_localtime_filename()

◆ hls_append_segment()

◆ parse_playlist()

◆ hls_free_segments()

◆ hls_rename_temp_file()

◆ get_relative_url()

◆ get_stream_bit_rate()

◆ create_master_playlist()

◆ hls_window()

◆ hls_start()

◆ get_default_pattern_localtime_fmt()

◆ append_postfix()

◆ validate_name()

◆ format_name()

◆ get_nth_codec_stream_index()

◆ parse_variant_stream_mapstring()

◆ parse_cc_stream_mapstring()

◆ update_variant_stream_info()

◆ update_master_pl_info()

◆ hls_write_header()

◆ hls_init_file_resend()

◆ append_single_file()

◆ hls_write_packet()

◆ hls_deinit()

◆ hls_write_trailer()

◆ hls_init()

Variable Documentation

◆ options

◆ hls_class

◆ ff_hls_muxer