Fragmented ISOBMFF Read

Collaboration diagram for Fragmented ISOBMFF Read:

Data Structures
struct	GF_ISOFragmentBoundaryInfo

Enumerations
enum	GF_ISOSegOpenMode { GF_ISOM_SEGMENT_NO_ORDER_FLAG = 1 , GF_ISOM_SEGMENT_SCALABLE_FLAG = 1<<1 }

Functions
Bool	gf_isom_is_fragmented (GF_ISOFile *isom_file)
Bool	gf_isom_is_track_fragmented (GF_ISOFile *isom_file, GF_ISOTrackID TrackID)
Bool	gf_isom_has_segment (GF_ISOFile *isom_file, u32 *brand, u32 *version)
u32	gf_isom_segment_get_fragment_count (GF_ISOFile *isom_file)
u32	gf_isom_segment_get_track_fragment_count (GF_ISOFile *isom_file, u32 moof_index)
u32	gf_isom_segment_get_track_fragment_decode_time (GF_ISOFile *isom_file, u32 moof_index, u32 traf_index, u64 *decode_time)
u64	gf_isom_segment_get_fragment_size (GF_ISOFile *isom_file, u32 moof_index, u32 *moof_size)
void	gf_isom_set_single_moof_mode (GF_ISOFile *isom_file, Bool mode)
GF_Err	gf_isom_get_file_offset_for_time (GF_ISOFile *isom_file, Double start_time, u64 *offset)
GF_Err	gf_isom_get_sidx_duration (GF_ISOFile *isom_file, u64 *sidx_dur, u32 *sidx_timescale)
GF_Err	gf_isom_refresh_fragmented (GF_ISOFile *isom_file, u64 *MissingBytes, const char *new_location)
u64	gf_isom_get_current_tfdt (GF_ISOFile *isom_file, u32 trackNumber)
u64	gf_isom_get_smooth_next_tfdt (GF_ISOFile *isom_file, u32 trackNumber)
Bool	gf_isom_is_smooth_streaming_moov (GF_ISOFile *isom_file)
GF_Err	gf_isom_get_fragment_defaults (GF_ISOFile *isom_file, u32 trackNumber, u32 *defaultDuration, u32 *defaultSize, u32 *defaultDescriptionIndex, u32 *defaultRandomAccess, u8 *defaultPadding, u16 *defaultDegradationPriority)
Bool	gf_isom_get_last_producer_time_box (GF_ISOFile *isom_file, GF_ISOTrackID *refTrackID, u64 *ntp, u64 *timestamp, Bool reset_info)
void	gf_isom_enable_traf_map_templates (GF_ISOFile *isom_file)
Bool	gf_isom_get_root_sidx_offsets (GF_ISOFile *isom_file, u64 *start, u64 *end)
Bool	gf_isom_sample_is_fragment_start (GF_ISOFile *isom_file, u32 trackNumber, u32 sampleNum, GF_ISOFragmentBoundaryInfo *frag_info)
GF_Err	gf_isom_release_segment (GF_ISOFile *isom_file, Bool reset_tables)
GF_Err	gf_isom_reset_tables (GF_ISOFile *isom_file, Bool reset_sample_count)
GF_Err	gf_isom_reset_data_offset (GF_ISOFile *isom_file, u64 *top_box_start)
GF_Err	gf_isom_open_segment (GF_ISOFile *isom_file, const char *fileName, u64 start_range, u64 end_range, GF_ISOSegOpenMode flags)
GF_ISOTrackID	gf_isom_get_highest_track_in_scalable_segment (GF_ISOFile *isom_file, u32 for_base_track)
void	gf_isom_reset_fragment_info (GF_ISOFile *isom_file, Bool keep_sample_count)
void	gf_isom_reset_sample_count (GF_ISOFile *isom_file)
void	gf_isom_reset_seq_num (GF_ISOFile *isom_file)
u64	gf_isom_get_fragmented_duration (GF_ISOFile *isom_file)
u32	gf_isom_get_fragments_count (GF_ISOFile *isom_file, Bool segments_only)
GF_Err	gf_isom_get_fragmented_samples_info (GF_ISOFile *isom_file, GF_ISOTrackID trackID, u32 *nb_samples, u64 *duration)
u32	gf_isom_get_next_moof_number (GF_ISOFile *isom_file)

Detailed Description

This describes function specific to fragmented ISOBMF files

---

Data Structure Documentation

GF_ISOFragmentBoundaryInfo

struct GF_ISOFragmentBoundaryInfo

Segment boundary information

Data Fields
u64	frag_start	fragment start offset
u64	mdat_end	mdat end offset
u64	seg_start_plus_one
const u8 *	moof_template	serialized array of styp (if present) sidx (if present) and moof with only the current traf
u32	moof_template_size	size of serialized buffer
u64	sidx_start	sidx start, 0 if absent
u64	sidx_end	sidx end, 0 if absent
u64	first_dts	DTS of first sample in this fragment fotr the queried track

Enumeration Type Documentation

GF_ISOSegOpenMode

enum GF_ISOSegOpenMode

Flags for gf_isom_open_segment

Enumerator
GF_ISOM_SEGMENT_NO_ORDER_FLAG	do not check for movie fragment sequence number
GF_ISOM_SEGMENT_SCALABLE_FLAG	the segment contains a scalable layer of the last opened segment

Function Documentation

gf_isom_is_fragmented()

Bool gf_isom_is_fragmented

(

GF_ISOFile *

isom_file

)

checks if a movie file is fragmented

Parameters

isom_file

the target ISO file

Returns

GF_FALSE if movie isn't fragmented, GF_TRUE otherwise

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gf_isom_is_track_fragmented()

Bool gf_isom_is_track_fragmented	(	GF_ISOFile *	isom_file,
		GF_ISOTrackID	TrackID
	)

checks if a movie file is fragmented

Parameters

isom_file	the target ISO file
TrackID	the target track

Returns

GF_FALSE if track isn't fragmented, GF_TRUE otherwise

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gf_isom_has_segment()

Bool gf_isom_has_segment	(	GF_ISOFile *	isom_file,
		u32 *	brand,
		u32 *	version
	)

checks if a file has a top styp box

Parameters

isom_file	the target ISO file
brand	set to the major brand of the styp box
version	set to version of the styp box

Returns

GF_TRUE of the file has a styp box, GF_FALSE otherwise

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gf_isom_segment_get_fragment_count()

u32 gf_isom_segment_get_fragment_count

(

GF_ISOFile *

isom_file

)

gets number of movie fragments in the file

Parameters

isom_file

the target ISO file

Returns

number of movie fragments in the file, 0 if none

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gf_isom_segment_get_track_fragment_count()

u32 gf_isom_segment_get_track_fragment_count	(	GF_ISOFile *	isom_file,
		u32	moof_index
	)

gets number of track fragments in the indicated movie fragment

Parameters

isom_file	the target ISO file
moof_index	the target movie fragment (1-based index)

Returns

number of track fragments, 0 if none

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gf_isom_segment_get_track_fragment_decode_time()

u32 gf_isom_segment_get_track_fragment_decode_time	(	GF_ISOFile *	isom_file,
		u32	moof_index,
		u32	traf_index,
		u64 *	decode_time
	)

get the track fragment decode time of a track fragment

Parameters

isom_file	the target ISO file
moof_index	the target movie fragment (1-based index)
traf_index	the target track fragment (1-based index)
decode_time	set to the track fragment decode time if present, 0 otherwise

Returns

the track ID of the track fragment

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gf_isom_segment_get_fragment_size()

u64 gf_isom_segment_get_fragment_size	(	GF_ISOFile *	isom_file,
		u32	moof_index,
		u32 *	moof_size
	)

get the movie fragment size, i.e. the size of moof, mdat and related boxes before moof/mdat

Parameters

isom_file	the target ISO file
moof_index	the target movie fragment (1-based index)
moof_size	set to moof box size, may be NULL

Returns

the movie fragemnt size

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gf_isom_set_single_moof_mode()

void gf_isom_set_single_moof_mode	(	GF_ISOFile *	isom_file,
		Bool	mode
	)

enables single moof mode. In single moof mode, file is parsed only one moof/mdat at a time in order to proceed to next moof, gf_isom_reset_data_offset must be called to parse the next moof

Parameters

isom_file	the target ISO file
mode	if GF_TRUE, enables single moof mode; otherwise disables it

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gf_isom_get_file_offset_for_time()

GF_Err gf_isom_get_file_offset_for_time	(	GF_ISOFile *	isom_file,
		Double	start_time,
		u64 *	offset
	)

gets closest file offset for the given time, when the file uses an segment index (sidx)

Parameters

isom_file	the target ISO file
start_time	the start time in seconds
offset	set to the file offset of the segment containing the desired time

Returns

error if any

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gf_isom_get_sidx_duration()

GF_Err gf_isom_get_sidx_duration	(	GF_ISOFile *	isom_file,
		u64 *	sidx_dur,
		u32 *	sidx_timescale
	)

gets sidx duration, when the file uses an segment index (sidx)

Parameters

isom_file	the target ISO file
sidx_dur	set to the total duration documented in the segment index
sidx_timescale	set timescale used to represent the duration in the segment index

Returns

error if any

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gf_isom_refresh_fragmented()

GF_Err gf_isom_refresh_fragmented	(	GF_ISOFile *	isom_file,
		u64 *	MissingBytes,
		const char *	new_location
	)

refreshes a fragmented file A file being downloaded may be a fragmented file. In this case only partial info is available once the file is successfully open (gf_isom_open_progressive), and since there is no information wrt number fragments (which could actually be generated on the fly at the sender side), you must call this function on regular basis in order to load newly downloaded fragments. Note this may result in Track/Movie duration changes and SampleCount change too ...

This function should also be called when using memory read (gmem://) to refresh the underlying bitstream after appendin data to your blob. In the case where the file is not fragmented, no further box parsing will be done.

Parameters

isom_file	the target ISO file
MissingBytes	set to the number of missing bytes to parse the last incomplete top-level box found
new_location	if set, the previous bitstream is changed to this new location, otherwise it is refreshed (disk flush)

Returns

error if any

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gf_isom_get_current_tfdt()

u64 gf_isom_get_current_tfdt	(	GF_ISOFile *	isom_file,
		u32	trackNumber
	)

gets the current track fragment decode time of the track (the one of the last fragment parsed).

Parameters

isom_file	the target ISO file
trackNumber	the target track

Returns

the track fragment decode time in media timescale

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gf_isom_get_smooth_next_tfdt()

u64 gf_isom_get_smooth_next_tfdt	(	GF_ISOFile *	isom_file,
		u32	trackNumber
	)

gets the estimated DTS of the first sample of the next segment for SmoothStreaming files (no tfdt, no tfxd)

Parameters

isom_file	the target ISO file
trackNumber	the target track

Returns

the next track fragment decode time in media timescale

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gf_isom_is_smooth_streaming_moov()

Bool gf_isom_is_smooth_streaming_moov

(

GF_ISOFile *

isom_file

)

checks if the movie is a smooth streaming recomputed initial movie

Parameters

isom_file

the target ISO file

Returns

GF_TRUE if the file init segment (moov) was generated from external meta-data (smooth streaming)

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gf_isom_get_fragment_defaults()

GF_Err gf_isom_get_fragment_defaults	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32 *	defaultDuration,
		u32 *	defaultSize,
		u32 *	defaultDescriptionIndex,
		u32 *	defaultRandomAccess,
		u8 *	defaultPadding,
		u16 *	defaultDegradationPriority
	)

gets default values of samples in a track to use for track fragments default. Each variable is optional and if set will contain the default value for this track samples

Parameters

isom_file	the target ISO file
trackNumber	the target track
defaultDuration	set to the default duration of samples, 0 if not computable
defaultSize	set to the default size of samples, 0 if not computable
defaultDescriptionIndex	set to the default sample description index of samples, 0 if not computable
defaultRandomAccess	set to the default sync flag of samples, 0 if not computable
defaultPadding	set to the default padding bits of samples, 0 if not computable
defaultDegradationPriority	set to the default degradation priority of samples, 0 if not computable

Returns

error if any

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gf_isom_get_last_producer_time_box()

Bool gf_isom_get_last_producer_time_box	(	GF_ISOFile *	isom_file,
		GF_ISOTrackID *	refTrackID,
		u64 *	ntp,
		u64 *	timestamp,
		Bool	reset_info
	)

gets last UTC/timestamp values indicated for the reference track in the file if any (pfrt box)

Parameters

isom_file	the target ISO file
refTrackID	set to the ID of the reference track used by the pfrt box
ntp	set to the NTP timestamp found
timestamp	set to the corresponding media timestamp in refTrackID timescale
reset_info	if GF_TRUE, discards current NTP mapping info; this will trigger parsing of the next prft box found. If not set, subsequent pfrt boxes will not be parsed until the function is called with reset_info=GF_TRUE

Returns

GF_FALSE if no info found, GF_TRUE if OK

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gf_isom_enable_traf_map_templates()

void gf_isom_enable_traf_map_templates

(

GF_ISOFile *

isom_file

)

enables storage of traf templates (serialized sidx/moof/traf without trun/senc) at segment boundaries This is mostly used to recreate identical segment information when refragmenting a file

Parameters

isom_file

the target ISO file

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gf_isom_get_root_sidx_offsets()

Bool gf_isom_get_root_sidx_offsets	(	GF_ISOFile *	isom_file,
		u64 *	start,
		u64 *	end
	)

get byte range of root sidx if any

Parameters

isom_file	the target ISO file
start	set to start offset (0=first byte) of the root sidx
end	set to end offset (0 if no sidx) of the root sidx

Returns

true if success

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gf_isom_sample_is_fragment_start()

Bool gf_isom_sample_is_fragment_start	(	GF_ISOFile *	isom_file,
		u32	trackNumber,
		u32	sampleNum,
		GF_ISOFragmentBoundaryInfo *	frag_info
	)

checks if a sample is a fragment start Only use this function if gf_isom_enable_traf_map_templates has been called

Parameters

isom_file	the target ISO file
trackNumber	the target track
sampleNum	the target sample number
frag_info	filled with information on fragment boundaries (optional - can be NULL)

Returns

GF_TRUE if this sample was the first sample of a traf in the fragmented source file, GF_FALSE otherwise

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gf_isom_release_segment()

GF_Err gf_isom_release_segment	(	GF_ISOFile *	isom_file,
		Bool	reset_tables
	)

releases current movie segment. This closes the associated file IO object.

Note

seeking in the file is no longer possible when tables are rested

Warning

The sample count is not reseted after the release of tables. use gf_isom_reset_tables for this

Parameters

isom_file	the target ISO file
reset_tables	if set, sample information for all tracks setup as segment are destroyed, along with all PSSH boxes. This allows keeping the memory footprint low when playing segments.

Returns

error if any

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gf_isom_reset_tables()

GF_Err gf_isom_reset_tables	(	GF_ISOFile *	isom_file,
		Bool	reset_sample_count
	)

resets sample information for all tracks setup. This allows keeping the memory footprint low when playing DASH/CMAF segments

Note

seeking in the file is then no longer possible

Parameters

isom_file	the target ISO file
reset_sample_count	if GF_TRUE, sets sample count of all tracks back to 0

Returns

error if any

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gf_isom_reset_data_offset()

GF_Err gf_isom_reset_data_offset	(	GF_ISOFile *	isom_file,
		u64 *	top_box_start
	)

sets the offset for parsing from the input buffer to 0 (used to reclaim input buffer)

Parameters

isom_file	the target ISO file
top_box_start	set to the byte offset in the source buffer of the first top level box, may be NULL

Returns

error if any

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gf_isom_open_segment()

GF_Err gf_isom_open_segment	(	GF_ISOFile *	isom_file,
		const char *	fileName,
		u64	start_range,
		u64	end_range,
		GF_ISOSegOpenMode	flags
	)

opens a new segment file. Access to samples in previous segments is no longer possible if end_range>start_range, restricts the URL to the given byterange when parsing

Parameters

isom_file	the target ISO file
fileName	the file name of the new segment to open
start_range	the start offset in bytes in the file of the segment data
end_range	the end offset in bytes in the file of the segment data
flags	flags to use when opening the segment

Returns

error if any

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gf_isom_get_highest_track_in_scalable_segment()

GF_ISOTrackID gf_isom_get_highest_track_in_scalable_segment	(	GF_ISOFile *	isom_file,
		u32	for_base_track
	)

returns the track ID of the track containing the highest enhancement layer for the given base track

Parameters

isom_file	the target ISO file
for_base_track	the number of the base track

Returns

the track ID of the highest enahnacement track

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gf_isom_reset_fragment_info()

void gf_isom_reset_fragment_info	(	GF_ISOFile *	isom_file,
		Bool	keep_sample_count
	)

resets internal info (track fragement decode time, number of samples, next moof number)used with fragments and segment.

Note

This should be called when seeking (with keep_sample_count=0) or when loading a media segments with the same timing as the previously loaded segment

Parameters

isom_file	the target ISO file
keep_sample_count	if GF_TRUE, does not reset the sample count on tracks

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gf_isom_reset_sample_count()

void gf_isom_reset_sample_count

(

GF_ISOFile *

isom_file

)

resets sample count to 0 and next moof number to 0. When doing scalable media, should be called before opening the segment containing the base layer in order to make sure the sample count base number is always the same (ie 1) on all tracks

Parameters

isom_file

the target ISO file

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gf_isom_reset_seq_num()

void gf_isom_reset_seq_num

(

GF_ISOFile *

isom_file

)

resets moof sequence number to 0

Parameters

isom_file

the target ISO file

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gf_isom_get_fragmented_duration()

u64 gf_isom_get_fragmented_duration

(

GF_ISOFile *

isom_file

)

gets the duration of movie+fragments

Parameters

isom_file

the target ISO file

Returns

the duration in movie timescale, 0 if unknown or if error

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gf_isom_get_fragments_count()

u32 gf_isom_get_fragments_count	(	GF_ISOFile *	isom_file,
		Bool	segments_only
	)

gets the number of fragments or segments when the file is opened in GF_ISOM_OPEN_READ_DUMP mode

Parameters

isom_file	the target ISO file
segments_only	if set to GF_TRUE, counts segments (sidx), otherwise counts fragments

Returns

the number of segments or fragments

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gf_isom_get_fragmented_samples_info()

GF_Err gf_isom_get_fragmented_samples_info	(	GF_ISOFile *	isom_file,
		GF_ISOTrackID	trackID,
		u32 *	nb_samples,
		u64 *	duration
	)

gets total sample number and duration when the file is opened in GF_ISOM_OPEN_READ_DUMP mode

Parameters

isom_file	the target ISO file
trackID	the ID of the target track
nb_samples	set to the number of samples in the track
duration	set to the total duration in media timescale

Returns

error if any

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gf_isom_get_next_moof_number()

u32 gf_isom_get_next_moof_number

(

GF_ISOFile *

isom_file

)

gets the number of the next moof to be produced

Parameters

isom_file

the target ISO file

Returns

number of the next moof

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