Subtitles and Timed Text

Collaboration diagram for Subtitles and Timed Text:

Typedefs
typedef struct _3gpp_text_sample	GF_TextSample
typedef struct _generic_subtitle_sample	GF_GenericSubtitleSample

Enumerations
enum	GF_TextDumpType {   GF_TEXTDUMPTYPE_TTXT = 0 , GF_TEXTDUMPTYPE_TTXT_BOXES , GF_TEXTDUMPTYPE_SRT , GF_TEXTDUMPTYPE_SVG ,   GF_TEXTDUMPTYPE_TTXT_CHAP , GF_TEXTDUMPTYPE_OGG_CHAP , GF_TEXTDUMPTYPE_ZOOM_CHAP }
enum	GF_TextFlagsMode { GF_ISOM_TEXT_FLAGS_OVERWRITE = 0 , GF_ISOM_TEXT_FLAGS_TOGGLE , GF_ISOM_TEXT_FLAGS_UNTOGGLE }

Functions
GF_Err	gf_isom_text_set_streaming_mode (GF_ISOFile *isom_file, Bool do_convert)
GF_Err	gf_isom_text_dump (GF_ISOFile *isom_file, u32 trackNumber, FILE *dump, GF_TextDumpType dump_type)
GF_Err	gf_isom_text_get_encoded_tx3g (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex, u32 sidx_offset, u8 **tx3g, u32 *tx3g_size)
GF_Err	gf_isom_set_forced_text (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex, u32 force_type)
GF_TextSample *	gf_isom_new_text_sample ()
void	gf_isom_delete_text_sample (GF_TextSample *tx_samp)
GF_GenericSubtitleSample *	gf_isom_new_generic_subtitle_sample ()
void	gf_isom_delete_generic_subtitle_sample (GF_GenericSubtitleSample *generic_subtitle_samp)
GF_Err	gf_isom_new_webvtt_description (GF_ISOFile *isom_file, u32 trackNumber, const char *URLname, const char *URNname, u32 *outDescriptionIndex, const char *config)
const char *	gf_isom_get_webvtt_config (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex)
GF_Err	gf_isom_stxt_get_description (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex, const char **mime, const char **encoding, const char **config)
GF_Err	gf_isom_new_stxt_description (GF_ISOFile *isom_file, u32 trackNumber, u32 type, const char *mime, const char *encoding, const char *config, u32 *outDescriptionIndex)
GF_Err	gf_isom_xml_subtitle_get_description (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex, const char **xmlnamespace, const char **xml_schema_loc, const char **mimes)
GF_Err	gf_isom_new_xml_subtitle_description (GF_ISOFile *isom_file, u32 trackNumber, const char *xmlnamespace, const char *xml_schema_loc, const char *auxiliary_mimes, u32 *outDescriptionIndex)
const char *	gf_isom_subtitle_get_mime (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex)
GF_Err	gf_isom_subtitle_set_mime (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex, const char *full_mime)
GF_Err	gf_isom_get_xml_metadata_description (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex, const char **xmlnamespace, const char **schema_loc, const char **content_encoding)
GF_Err	gf_isom_new_xml_metadata_description (GF_ISOFile *isom_file, u32 trackNumber, const char *xmlnamespace, const char *schema_loc, const char *content_encoding, u32 *outDescriptionIndex)
GF_Err	gf_isom_text_set_display_flags (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex, u32 flags, GF_TextFlagsMode op_type)
GF_Err	gf_isom_get_text_description (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleDescriptionIndex, GF_TextSampleDescriptor **out_desc)
GF_Err	gf_isom_new_text_description (GF_ISOFile *isom_file, u32 trackNumber, GF_TextSampleDescriptor *desc, const char *URLname, const char *URNname, u32 *outDescriptionIndex)
GF_Err	gf_isom_text_reset (GF_TextSample *tx_samp)
GF_Err	gf_isom_text_reset_styles (GF_TextSample *tx_samp)
GF_Err	gf_isom_text_add_text (GF_TextSample *tx_samp, char *text_data, u32 text_len)
GF_Err	gf_isom_text_add_style (GF_TextSample *tx_samp, GF_StyleRecord *rec)
GF_Err	gf_isom_text_add_highlight (GF_TextSample *tx_samp, u16 start_char, u16 end_char)
GF_Err	gf_isom_text_set_highlight_color (GF_TextSample *tx_samp, u32 argb)
GF_Err	gf_isom_text_add_karaoke (GF_TextSample *tx_samp, u32 start_time)
GF_Err	gf_isom_text_set_karaoke_segment (GF_TextSample *tx_samp, u32 end_time, u16 start_char, u16 end_char)
GF_Err	gf_isom_text_set_scroll_delay (GF_TextSample *tx_samp, u32 scroll_delay)
GF_Err	gf_isom_text_add_hyperlink (GF_TextSample *tx_samp, char *URL, char *altString, u16 start_char, u16 end_char)
GF_Err	gf_isom_text_set_box (GF_TextSample *tx_samp, s16 top, s16 left, s16 bottom, s16 right)
GF_Err	gf_isom_text_add_blink (GF_TextSample *tx_samp, u16 start_char, u16 end_char)
GF_Err	gf_isom_text_set_wrap (GF_TextSample *tx_samp, u8 wrap_flags)
GF_Err	gf_isom_text_set_forced (GF_TextSample *tx_samp, Bool is_forced)
GF_Err	gf_isom_text_sample_write_bs (const GF_TextSample *tx_samp, GF_BitStream *bs)
GF_ISOSample *	gf_isom_text_to_sample (const GF_TextSample *tx_samp)
u32	gf_isom_text_sample_size (GF_TextSample *tx_samp)
GF_GenericSubtitleSample *	gf_isom_new_xml_subtitle_sample ()
void	gf_isom_delete_xml_subtitle_sample (GF_GenericSubtitleSample *subt_samp)
GF_Err	gf_isom_xml_subtitle_reset (GF_GenericSubtitleSample *subt_samp)
GF_ISOSample *	gf_isom_xml_subtitle_to_sample (GF_GenericSubtitleSample *subt_samp)
GF_Err	gf_isom_xml_subtitle_sample_add_text (GF_GenericSubtitleSample *subt_samp, char *text_data, u32 text_len)

Detailed Description

Typedef Documentation

GF_TextSample

typedef struct _3gpp_text_sample GF_TextSample

text sample formatting

GF_GenericSubtitleSample

typedef struct _generic_subtitle_sample GF_GenericSubtitleSample

generic subtitle sample formatting

Enumeration Type Documentation

GF_TextDumpType

enum GF_TextDumpType

text track export type

Enumerator
GF_TEXTDUMPTYPE_TTXT	dump as TTXT XML
GF_TEXTDUMPTYPE_TTXT_BOXES	dump as TTXT XML with box
GF_TEXTDUMPTYPE_SRT	dump as SRT
GF_TEXTDUMPTYPE_SVG	dump as SVG
GF_TEXTDUMPTYPE_TTXT_CHAP	dump as TTXT chapters (omits empty text samples)
GF_TEXTDUMPTYPE_OGG_CHAP	dump as OGG chapters
GF_TEXTDUMPTYPE_ZOOM_CHAP	dump as Zoom chapters

GF_TextFlagsMode

enum GF_TextFlagsMode

text flags operation type

Function Documentation

gf_isom_text_set_streaming_mode()

GF_Err gf_isom_text_set_streaming_mode	(	GF_ISOFile *	isom_file,
		Bool	do_convert
	)

sets streaming text reading mode (MPEG-4 text vs 3GPP)

Parameters

isom_file	the target ISO file
do_convert	is set, all text samples will be retrieved as TTUs and ESD will be emulated for text tracks

Returns

error if any

gf_isom_text_dump()

GF_Err gf_isom_text_dump	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		FILE *	dump,
		GF_TextDumpType	dump_type
	)

dumps a text track to a file

Parameters

isom_file	the target ISO file
trackNumber	the target track
dump	the file object to write to (binary open mode)
dump_type	the dump type mode

Returns

error if any

gf_isom_text_get_encoded_tx3g()

GF_Err gf_isom_text_get_encoded_tx3g	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex,
		u32	sidx_offset,
		u8 **	tx3g,
		u32 *	tx3g_size
	)

gets encoded TX3G box (text sample description for 3GPP text streams) as needed by RTP or other standards:

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the sample description index
sidx_offset	if 0, the sidx will NOT be written before the encoded TX3G. If not 0, the sidx will be written before the encoded TX3G, with the given offset. Offset sshould be at least 128 for most common usage of TX3G (RTP, MPEG-4 timed text, etc)
tx3g	set to a newly allocated buffer containing the encoded tx3g - to be freed by caller
tx3g_size	set to the size of the encoded config

Returns

error if any

gf_isom_set_forced_text()

GF_Err gf_isom_set_forced_text	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex,
		u32	force_type
	)

sets TX3G flags for forced samples

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the sample description index
force_type	if 0, no forced subs are present. If 1, some forced subs are present; if 2, all samples are forced subs

Returns

error if any

gf_isom_new_text_sample()

GF_TextSample* gf_isom_new_text_sample

(

)

creates text sample handle

Returns

a newly allocated text sample

gf_isom_delete_text_sample()

void gf_isom_delete_text_sample

(

GF_TextSample *

tx_samp

)

destroys text sample handle

Parameters

tx_samp

the target text sample

gf_isom_new_generic_subtitle_sample()

GF_GenericSubtitleSample* gf_isom_new_generic_subtitle_sample

(

)

creates generic subtitle sample handle

Returns

a newly allocated generic subtitle sample

gf_isom_delete_generic_subtitle_sample()

void gf_isom_delete_generic_subtitle_sample

(

GF_GenericSubtitleSample *

generic_subtitle_samp

)

destroys generic subtitle sample handle

Parameters

generic_subtitle_samp

the target generic subtitle sample

gf_isom_new_webvtt_description()

GF_Err gf_isom_new_webvtt_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		const char *	URLname,
		const char *	URNname,
		u32 *	outDescriptionIndex,
		const char *	config
	)

creates new WebVTT config

Parameters

isom_file	the target ISO file
trackNumber	the target track
URLname	URL value of the data reference, NULL if no data reference (media in the file)
URNname	URN value of the data reference, NULL if no data reference (media in the file)
outDescriptionIndex	set to the index of the created sample description
config	the WebVTT configuration string

Returns

error if any

gf_isom_get_webvtt_config()

const char* gf_isom_get_webvtt_config	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex
	)

gets WebVTT config for a sample description

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the target sample description index

Returns

the WebVTT configuration string

gf_isom_stxt_get_description()

GF_Err gf_isom_stxt_get_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex,
		const char **	mime,
		const char **	encoding,
		const char **	config
	)

gets simple streaming text config for a sample description

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the target sample description index
mime	set to the mime type (optional, can be NULL)
encoding	set to the text encoding type (optional, can be NULL)
config	set to the WebVTT configuration string (optional, can be NULL)

Returns

error if any

gf_isom_new_stxt_description()

GF_Err gf_isom_new_stxt_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	type,
		const char *	mime,
		const char *	encoding,
		const char *	config,
		u32 *	outDescriptionIndex
	)

creates new simple streaming text config

Parameters

isom_file	the target ISO file
trackNumber	the target track
type	the four character code of the simple text sample description (sbtt, stxt, mett)
mime	the mime type
encoding	the text encoding, if any
config	the configuration string, if any
outDescriptionIndex	set to the index of the created sample description

Returns

error if any

gf_isom_xml_subtitle_get_description()

GF_Err gf_isom_xml_subtitle_get_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex,
		const char **	xmlnamespace,
		const char **	xml_schema_loc,
		const char **	mimes
	)

gets XML streaming text config for a sample description

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the target sample description index
xmlnamespace	set to the XML namespace (optional, can be NULL)
xml_schema_loc	set to the XML schema location (optional, can be NULL)
mimes	set to the associated mime(s) types (optional, can be NULL)

Returns

error if any

gf_isom_new_xml_subtitle_description()

GF_Err gf_isom_new_xml_subtitle_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		const char *	xmlnamespace,
		const char *	xml_schema_loc,
		const char *	auxiliary_mimes,
		u32 *	outDescriptionIndex
	)

creates a new XML streaming text config

Parameters

isom_file	the target ISO file
trackNumber	the target track
xmlnamespace	the XML namespace
xml_schema_loc	the XML schema location (optional, can be NULL)
auxiliary_mimes	the associated mime(s) types (optional, can be NULL)
outDescriptionIndex	set to the index of the created sample description

Returns

error if any

gf_isom_subtitle_get_mime()

const char* gf_isom_subtitle_get_mime	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex
	)

gets MIME parameters (type/subtype + codecs and profiles) associated with a sample descritpion

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the target sample description index

Returns

MIME param if present, NULL otherwise

gf_isom_subtitle_set_mime()

GF_Err gf_isom_subtitle_set_mime	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex,
		const char *	full_mime
	)

gets MIME parameters associated with a sample descritpion

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the target sample description index
full_mime	MIME param (type/subtype + codecs and profiles) to set, if NULL removes MIME parameter info

Returns

error if any

gf_isom_get_xml_metadata_description()

GF_Err gf_isom_get_xml_metadata_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex,
		const char **	xmlnamespace,
		const char **	schema_loc,
		const char **	content_encoding
	)

gets XML metadata for a sample description

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the target sample description index
xmlnamespace	set to the XML namespace (optional, can be NULL)
schema_loc	set to the XML schema location (optional, can be NULL)
content_encoding	set to the content encoding string (optional, can be NULL)

Returns

error if any

gf_isom_new_xml_metadata_description()

GF_Err gf_isom_new_xml_metadata_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		const char *	xmlnamespace,
		const char *	schema_loc,
		const char *	content_encoding,
		u32 *	outDescriptionIndex
	)

creates a new timed metadata sample description for this track

Parameters

isom_file	the target ISO file
trackNumber	the target track
xmlnamespace	the XML namespace
schema_loc	the XML schema location (optional, can be NULL)
content_encoding	the content encoding string (optional, can be NULL)
outDescriptionIndex	set to the index of the created sample description

Returns

error if any

gf_isom_text_set_display_flags()

GF_Err gf_isom_text_set_display_flags	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex,
		u32	flags,
		GF_TextFlagsMode	op_type
	)

sets text display flags according to given mode.

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the target sample description index. If 0, sets the flags for all text descriptions
flags	the flag to set
op_type	the flag toggle mode

Returns

error if any

gf_isom_get_text_description()

GF_Err gf_isom_get_text_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleDescriptionIndex,
		GF_TextSampleDescriptor **	out_desc
	)

gets text description of a sample description

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleDescriptionIndex	the target sample description index
out_desc	set to a newly allocated text sample descriptor - shall be freeed by user

Returns

error if any

gf_isom_new_text_description()

GF_Err gf_isom_new_text_description	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		GF_TextSampleDescriptor *	desc,
		const char *	URLname,
		const char *	URNname,
		u32 *	outDescriptionIndex
	)

creates a new TextSampleDescription in the file.

Parameters

isom_file	the target ISO file
trackNumber	the target track
desc	the text sample description
URLname	URL value of the data reference, NULL if no data reference (media in the file)
URNname	URN value of the data reference, NULL if no data reference (media in the file)
outDescriptionIndex	set to the index of the created sample description

Returns

error if any

gf_isom_text_reset()

GF_Err gf_isom_text_reset

(

GF_TextSample *

tx_samp

)

resets text sample content

Parameters

tx_samp

the target text sample

Returns

error if any

gf_isom_text_reset_styles()

GF_Err gf_isom_text_reset_styles

(

GF_TextSample *

tx_samp

)

resets text sample styles but keep text

Parameters

tx_samp

the target text sample

Returns

error if any

gf_isom_text_add_text()

GF_Err gf_isom_text_add_text	(	GF_TextSample *	tx_samp,
		char *	text_data,
		u32	text_len
	)

appends text to sample - text_len is the number of bytes to be written from text_data. This allows handling UTF8 and UTF16 strings in a transparent manner

Parameters

tx_samp	the target text sample
text_data	the text data to add
text_len	the size of the data to add

Returns

error if any

gf_isom_text_add_style()

GF_Err gf_isom_text_add_style	(	GF_TextSample *	tx_samp,
		GF_StyleRecord *	rec
	)

appends style modifyer to sample

Parameters

tx_samp	the target text sample
rec	the style record to add

Returns

error if any

gf_isom_text_add_highlight()

GF_Err gf_isom_text_add_highlight	(	GF_TextSample *	tx_samp,
		u16	start_char,
		u16	end_char
	)

appends highlight modifier for the sample

Parameters

tx_samp	the target text sample
start_char	first char highlighted,
end_char	first char not highlighted

Returns

error if any

gf_isom_text_set_highlight_color()

GF_Err gf_isom_text_set_highlight_color	(	GF_TextSample *	tx_samp,
		u32	argb
	)

sets highlight color for the whole sample

Parameters

tx_samp	the target text sample
argb	color value

Returns

error if any

gf_isom_text_add_karaoke()

GF_Err gf_isom_text_add_karaoke	(	GF_TextSample *	tx_samp,
		u32	start_time
	)

appends a new karaoke sequence in the sample

Parameters

tx_samp	the target text sample
start_time	karaoke start time expressed in text stream timescale, but relative to the sample media time

Returns

error if any

gf_isom_text_set_karaoke_segment()

GF_Err gf_isom_text_set_karaoke_segment	(	GF_TextSample *	tx_samp,
		u32	end_time,
		u16	start_char,
		u16	end_char
	)

appends a new segment in the current karaoke sequence - you must build sequences in order to be compliant

Parameters

tx_samp	the target text sample
end_time	segment end time expressed in text stream timescale, but relative to the sample media time
start_char	first char highlighted,
end_char	first char not highlighted

Returns

error if any

gf_isom_text_set_scroll_delay()

GF_Err gf_isom_text_set_scroll_delay	(	GF_TextSample *	tx_samp,
		u32	scroll_delay
	)

sets scroll delay for the whole sample (scrolling is enabled through GF_TextSampleDescriptor.DisplayFlags)

Parameters

tx_samp	the target text sample
scroll_delay	delay for scrolling expressed in text stream timescale

Returns

error if any

gf_isom_text_add_hyperlink()

GF_Err gf_isom_text_add_hyperlink	(	GF_TextSample *	tx_samp,
		char *	URL,
		char *	altString,
		u16	start_char,
		u16	end_char
	)

appends hyperlinking for the sample

Parameters

tx_samp	the target text sample
URL	UTF-8 url
altString	UTF-8 hint (tooltip, ...) for end user
start_char	first char hyperlinked,
end_char	first char not hyperlinked

Returns

error if any

gf_isom_text_set_box()

GF_Err gf_isom_text_set_box	(	GF_TextSample *	tx_samp,
		s16	top,
		s16	left,
		s16	bottom,
		s16	right
	)

sets current text box (display pos&size within the text track window) for the sample

Parameters

tx_samp	the target text sample
top	top coordinate of box
left	left coordinate of box
bottom	bottom coordinate of box
right	right coordinate of box

Returns

error if any

gf_isom_text_add_blink()

GF_Err gf_isom_text_add_blink	(	GF_TextSample *	tx_samp,
		u16	start_char,
		u16	end_char
	)

appends blinking for the sample

Parameters

tx_samp	the target text sample
start_char	first char blinking,
end_char	first char not blinking

Returns

error if any

gf_isom_text_set_wrap()

GF_Err gf_isom_text_set_wrap	(	GF_TextSample *	tx_samp,
		u8	wrap_flags
	)

sets wrap flag for the sample

Parameters

tx_samp	the target text sample
wrap_flags	text wrap flags - currently only 0 (no wrap) and 1 ("soft wrap") are allowed in 3GP

Returns

error if any

gf_isom_text_set_forced()

GF_Err gf_isom_text_set_forced	(	GF_TextSample *	tx_samp,
		Bool	is_forced
	)

sets force for the sample

Parameters

tx_samp	the target text sample
is_forced	for ce sample if TRUE

Returns

error if any

gf_isom_text_sample_write_bs()

GF_Err gf_isom_text_sample_write_bs	(	const GF_TextSample *	tx_samp,
		GF_BitStream *	bs
	)

formats sample as a regular GF_ISOSample payload in a bitstream object.

Parameters

tx_samp	the target text sample
bs	thetarget bitstream

Returns

error if any

gf_isom_text_to_sample()

GF_ISOSample* gf_isom_text_to_sample

(

const GF_TextSample *

tx_samp

)

formats sample as a regular GF_ISOSample. The resulting sample will always be marked as random access

Parameters

tx_samp

the target text sample

Returns

the corresponding serialized ISO sample

gf_isom_text_sample_size()

u32 gf_isom_text_sample_size

(

GF_TextSample *

tx_samp

)

gets the serialized size of the text sample

Parameters

tx_samp

the target text sample

Returns

the serialized size

gf_isom_new_xml_subtitle_sample()

GF_GenericSubtitleSample* gf_isom_new_xml_subtitle_sample

(

)

creates a new XML subtitle sample

Returns

a new XML subtitle sample

gf_isom_delete_xml_subtitle_sample()

void gf_isom_delete_xml_subtitle_sample

(

GF_GenericSubtitleSample *

subt_samp

)

deletes an XML subtitle sample

Parameters

subt_samp

the target XML subtitle sample

gf_isom_xml_subtitle_reset()

GF_Err gf_isom_xml_subtitle_reset

(

GF_GenericSubtitleSample *

subt_samp

)

resets content of an XML subtitle sample

Parameters

subt_samp

the target XML subtitle sample

Returns

error if any

gf_isom_xml_subtitle_to_sample()

GF_ISOSample* gf_isom_xml_subtitle_to_sample

(

GF_GenericSubtitleSample *

subt_samp

)

the corresponding serialized ISO sample

Parameters

subt_samp

the target XML subtitle sample

Returns

the corresponding serialized ISO sample

gf_isom_xml_subtitle_sample_add_text()

GF_Err gf_isom_xml_subtitle_sample_add_text	(	GF_GenericSubtitleSample *	subt_samp,
		char *	text_data,
		u32	text_len
	)

appends text to an XML subtitle sample

Parameters

subt_samp	the target XML subtitle sample
text_data	the UTF-8 or UTF-16 data to add
text_len	the size of the text to add in bytes

Returns

error if any