DemuxerAVI Class Reference

AVI Container Decoder which can be fed with small chunks of data. The minimum length must be bigger then the header size! The file structure is documented at https://learn.microsoft.com/en-us/windows/win32/directshow/avi-riff-file-reference. More...

#include <ContainerAVI.h>

Inheritance diagram for DemuxerAVI:

Public Member Functions
	DemuxerAVI (int bufferSize=1024)
virtual void	addNotifyAudioChange (AudioInfoSupport &bi)
	Adds target to be notified about audio changes.
AudioInfo	audioInfo () override
	provides the actual input AudioInfo
virtual AudioInfo	audioInfoOut ()
WAVFormatX	aviAudioInfo ()
	Provides the audio information.
AVIMainHeader	aviMainHeader ()
	Provides the information from the main header chunk.
AVIStreamHeader	aviStreamHeader (int idx)
	Provides the information from the stream header chunks.
const char *	aviVideoFormat ()
BitmapInfoHeader	aviVideoInfo ()
	Provides the video information.
bool	begin () override
virtual bool	begin (AudioInfo info) override
virtual void	clearNotifyAudioChange ()
	Deletes all change notify subscriptions.
void	end () override
AudioInfoFormat	getAudioInfo () override
Print *	getOutput ()
VideoInfo	getVideoInfo () override
bool	isMetadataReady ()
	Returns true if all metadata has been parsed and is available.
bool	isNotifyActive ()
	Checks if the automatic AudioInfo update is active.
bool	isValid (const uint8_t *data, size_t len) override
const char *	mime () override
	provides the audio mime
const char *	mimeVideo ()
	Provides the video mime.
	operator bool () override
virtual bool	removeNotifyAudioChange (AudioInfoSupport &bi)
	Removes a target in order not to be notified about audio changes.
void	setAudioInfo (AudioInfo from) override
	for most decoders this is not needed
virtual bool	setCodecConfig (const uint8_t *data, size_t len)
	Some decoders need e.g. a magic cookie to provide the relevant info for decoding.
void	setMute (bool mute)
void	setNotifyActive (bool flag)
	Deactivate/Reactivate automatic AudioInfo updates: (default is active)
virtual void	setOutput (AudioOutput &out_stream)
	Defines where the decoded result is written to.
virtual void	setOutput (AudioStream &out_stream)
	Defines where the decoded result is written to.
virtual void	setOutput (Print &out_stream) override
void	setOutputAudio (Print &out_stream) override
void	setOutputVideo (Print &out_stream) override
void	setOutputVideo (VideoOutput &out_stream) override
void	setSendWavHeader (bool flag) override
void	setValidationCallback (bool(*cb)(DemuxerAVI &avi))
VideoInfo	videoInfo () override
int	videoSeconds ()
	Provide the length of the video in seconds.
virtual size_t	write (const uint8_t *data, size_t len) override

Public Attributes
int	id
	custom id to be used by application

Protected Member Functions
void	cleanupStack ()
void	consume (int len)
	We remove the processed bytes from the beginning of the buffer.
uint32_t	getInt (int offset)
	Provides the int32 at the indicated byte offset.
StrView &	getStr (int offset, int len)
	Provides the string at the indicated byte offset with the indicated length.
bool	isCurrentStreamAudio ()
bool	isCurrentStreamVideo ()
void	notifyAudioChange (AudioInfo info)
bool	parse ()
ParseObject	parseAVIStreamData ()
ParseObject	parseChunk (const char *id)
	We load the indicated chunk from the current data.
bool	parseHeader ()
ParseObject	parseList (const char *id)
	We load the indicated list from the current data.
void	processStack (ParseObject &result)
void	sendWavHeader ()
void	setupAudioInfo ()
void	setupVideoInfo ()
ParseObject	tryParseChunk ()
ParseObject	tryParseChunk (const char *id)
ParseObject	tryParseList ()
	We try to parse the actual state for any list.
ParseObject	tryParseList (const char *id)
void	writeBlocking (Print *out, uint8_t *data, size_t len)
void	writeData ()

Static Protected Member Functions
static VideoFormat	toVideoFormat (uint32_t biCompression, uint16_t biBitCount)

Protected Attributes
WAVFormatX	audio_info
Vector< StreamContentType >	content_types
long	current_pos = 0
ParseObject	current_stream_data
bool	header_is_avi = false
AudioInfo	info
bool	is_metadata_ready = false
bool	is_mute = false
bool	is_notify_active = true
bool	is_parsing_active = true
bool	is_wav_header_sent = false
AVIMainHeader	main_header
long	movi_end_pos = 0
Vector< AudioInfoSupport * >	notify_vector
Stack< ParseObject >	object_stack
long	open_subchunk_len = 0
Print *	p_output_audio = nullptr
Print *	p_output_video = nullptr
VideoOutput *	p_output_video_video = nullptr
Print *	p_print = nullptr
ParseBuffer	parse_buffer
ParseState	parse_state = ParseHeader
uint32_t	riff_file_size = 0
bool	send_wav_header = false
bool	send_wav_header_explicit = false
Str	spaces
Str	str
Vector< AVIStreamHeader >	stream_header
int	stream_header_idx = -1
bool(*	validation_cb )(DemuxerAVI &avi) = nullptr
Vector< uint8_t >	video_accumulator
char	video_format [5] = {0}
BitmapInfoHeader	video_info
int	video_seconds = 0

Detailed Description

AVI Container Decoder which can be fed with small chunks of data. The minimum length must be bigger then the header size! The file structure is documented at https://learn.microsoft.com/en-us/windows/win32/directshow/avi-riff-file-reference.

Author

Phil Schatzmann

Copyright

GPLv3

Constructor & Destructor Documentation

DemuxerAVI()

DemuxerAVI ( int  bufferSize = 1024 )

inline

Parameters

bufferSize

internal parse buffer size.

This class only demuxes - it does not decode audio itself. Point setOutputAudio() at an EncodedAudioStream (wrapping whatever AudioDecoder matches the AVI's audio format) if you need the audio track decoded; the raw payload is written through as-is otherwise. Point setOutputVideo() at a Print (e.g. a VideoOutput) to receive the demuxed video track; leave unset to ignore video.

Member Function Documentation

addNotifyAudioChange()

virtual void addNotifyAudioChange ( AudioInfoSupport &  bi )

inlinevirtualinherited

Adds target to be notified about audio changes.

Reimplemented in CodecNOP, EncodedAudioOutput, EncodedAudioStream, AACDecoderFDK, DecoderBasic, CodecChain, MP3DecoderHelix, MP3DecoderMAD, OggContainerDecoder, RTSPClient< TcpClient, UdpSocket >, Pipeline, and Pipeline::ModifyingStreamAdapter.

audioInfo()

AudioInfo audioInfo ( )

inlineoverridevirtualinherited

provides the actual input AudioInfo

Implements AudioInfoSupport.

Reimplemented in CodecNOP, DecoderBasic, DSFDecoder, MP3DecoderHelix, MP3DecoderMAD, OpusAudioDecoder, OpusMultiStreamAudioDecoder, VorbisDecoder, WAVDecoder, WavIMADecoder, OggContainerDecoder, and VorbisDecoder.

audioInfoOut()

virtual AudioInfo audioInfoOut ( )

inlinevirtualinherited

provides the actual output AudioInfo: this is usually the same as audioInfo() unless we use a transforming stream

Reimplemented in MP3EncoderShine, PureDataStream, PWMAudioOutput< PWMDriverT >, ChannelFormatConverterStreamT< T >, ChannelFormatConverterStream, NumberFormatConverterStreamT< TFrom, TTo >, NumberFormatConverterStream, FormatConverterStream, Pipeline, ResampleStream, ResampleStreamT< TInterpolator >, and SupportedRatesStream.

aviAudioInfo()

WAVFormatX aviAudioInfo ( )

inline

Provides the audio information.

aviMainHeader()

AVIMainHeader aviMainHeader ( )

inline

Provides the information from the main header chunk.

aviStreamHeader()

AVIStreamHeader aviStreamHeader ( int  idx )

inline

Provides the information from the stream header chunks.

aviVideoFormat()

const char * aviVideoFormat ( )

inline

aviVideoInfo()

BitmapInfoHeader aviVideoInfo ( )

inline

Provides the video information.

begin() [1/2]

bool begin ( )

inlineoverridevirtual

Reimplemented from AudioDecoder.

begin() [2/2]

virtual bool begin ( AudioInfo  info )

inlineoverridevirtualinherited

Reimplemented from AudioWriter.

Reimplemented in DecoderBasic, and OggContainerDecoder.

cleanupStack()

void cleanupStack ( )

inlineprotected

clearNotifyAudioChange()

virtual void clearNotifyAudioChange ( )

inlinevirtualinherited

Deletes all change notify subscriptions.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

consume()

void consume ( int  len )

inlineprotected

We remove the processed bytes from the beginning of the buffer.

end()

void end ( )

inlineoverridevirtual

Reimplemented from AudioDecoder.

getAudioInfo()

AudioInfoFormat getAudioInfo ( )

inlineoverridevirtual

Common audio info (sample_rate/channels/bits_per_sample), extended with the parsed 'strf' format tag - the same AudioInfoFormat type is also provided by DemuxerMP4. Named getAudioInfo() rather than audioInfo() because AudioDecoder already declares a virtual AudioInfo audioInfo() (returning the plain, unextended type by value) - by-value virtual returns can't be covariantly widened in C++, so reusing that name for a subclass-returning version isn't possible (it would be a hard "invalid covariant return type" error, not silent hiding).

Implements Demuxer.

getInt()

uint32_t getInt ( int  offset )

inlineprotected

Provides the int32 at the indicated byte offset.

getOutput()

Print * getOutput ( )

inlineinherited

getStr()

StrView & getStr ( int  offset, int  len  )

inlineprotected

Provides the string at the indicated byte offset with the indicated length.

getVideoInfo()

VideoInfo getVideoInfo ( )

inlineoverridevirtual

Common video info (width/height/format/frame_size/total_file_size), analogous to audioInfo() - the same VideoInfo type is also provided by DemuxerMP4. format is decoded from the 'strf' biCompression field (the authoritative codec id; more reliable than the 'strh' handler text for third-party files, available separately via videoFormat()); VideoFormat::UNKNOWN for any codec not covered by the enum.

Implements Demuxer.

isCurrentStreamAudio()

bool isCurrentStreamAudio ( )

inlineprotected

isCurrentStreamVideo()

bool isCurrentStreamVideo ( )

inlineprotected

isMetadataReady()

bool isMetadataReady ( )

inline

Returns true if all metadata has been parsed and is available.

isNotifyActive()

bool isNotifyActive ( )

inlineinherited

Checks if the automatic AudioInfo update is active.

isValid()

bool isValid ( const uint8_t *  data, size_t  len  )

inlineoverridevirtual

True if data starts with a RIFF header declaring an AVI file ("RIFF" at offset 0, "AVI " at offset 8) - see Demuxer::isValid().

Reimplemented from Demuxer.

mime()

const char * mime ( )

inlineoverridevirtual

provides the audio mime

Implements Demuxer.

mimeVideo()

const char * mimeVideo ( )

inlinevirtual

Provides the video mime.

Implements Demuxer.

notifyAudioChange()

void notifyAudioChange ( AudioInfo  info )

inlineprotectedinherited

operator bool()

operator bool ( )

inlineoverridevirtual

Implements AudioWriter.

parse()

bool parse ( )

inlineprotected

parseAVIStreamData()

ParseObject parseAVIStreamData ( )

inlineprotected

parseChunk()

ParseObject parseChunk ( const char *  id )

inlineprotected

We load the indicated chunk from the current data.

parseHeader()

bool parseHeader ( )

inlineprotected

parseList()

ParseObject parseList ( const char *  id )

inlineprotected

We load the indicated list from the current data.

processStack()

void processStack ( ParseObject &  result )

inlineprotected

removeNotifyAudioChange()

virtual bool removeNotifyAudioChange ( AudioInfoSupport &  bi )

inlinevirtualinherited

Removes a target in order not to be notified about audio changes.

Reimplemented in RTSPClient< TcpClient, UdpSocket >.

sendWavHeader()

void sendWavHeader ( )

inlineprotected

Synthesizes a valid WAV header (via the shared WAVHeader writer - also correctly handles ADPCM's extra 'fmt ' extension + 'fact' chunk) from the parsed 'strf' audio_info and sends it to p_output_audio, once, before any real audio payload - so a WAVDecoder-based output can bootstrap itself from it. Length is written as streamed/unknown, since the AVI's audio track length is not known upfront while demuxing.

setAudioInfo()

void setAudioInfo ( AudioInfo  from )

inlineoverridevirtualinherited

for most decoders this is not needed

Implements AudioWriter.

Reimplemented in DecoderALAC, CodecChain, DSFDecoder, DecoderL8, OpusAudioDecoder, OpusMultiStreamAudioDecoder, CodecNOP, G729Decoder, and G7xxDecoder.

setCodecConfig()

virtual bool setCodecConfig ( const uint8_t *  data, size_t  len  )

inlinevirtualinherited

Some decoders need e.g. a magic cookie to provide the relevant info for decoding.

Reimplemented in DecoderALAC, and MultiDecoder.

setMute()

void setMute ( bool  mute )

inline

setNotifyActive()

void setNotifyActive ( bool  flag )

inlineinherited

Deactivate/Reactivate automatic AudioInfo updates: (default is active)

setOutput() [1/3]

virtual void setOutput ( AudioOutput &  out_stream )

inlinevirtualinherited

Defines where the decoded result is written to.

Reimplemented in ADTSDecoder, CodecChain, MTSDecoder, MTSDecoderTSDemux, and MetaDataFilterDecoder.

setOutput() [2/3]

virtual void setOutput ( AudioStream &  out_stream )

inlinevirtualinherited

Defines where the decoded result is written to.

Reimplemented in ADTSDecoder, CodecChain, MTSDecoder, MTSDecoderTSDemux, and MetaDataFilterDecoder.

setOutput() [3/3]

virtual void setOutput ( Print &  out_stream )

inlineoverridevirtual

Satisfies the AudioWriter/AudioDecoder interface - needed so EncodedAudioOutput/EncodedAudioStream's polymorphic AudioDecoder* wiring (which calls setOutput() through that base class pointer) still reaches the audio output correctly; delegates to setOutputAudio().

Reimplemented from AudioDecoder.

setOutputAudio()

void setOutputAudio ( Print &  out_stream )

inlineoverridevirtual

Defines the audio output stream - e.g. an EncodedAudioStream wrapping an AudioDecoder that matches the AVI's audio format, or any other Print if you want the raw payload as-is.

Implements Demuxer.

setOutputVideo() [1/2]

void setOutputVideo ( Print &  out )

inlineoverridevirtual

Defines the video output - e.g. a VideoOutput implementation, or any other Print if you want the raw payload as-is.

Implements Demuxer.

setOutputVideo() [2/2]

void setOutputVideo ( VideoOutput &  out )

inlineoverridevirtual

Defines the video output - the VideoOutput-specific counterpart of setOutputVideo(Print&), for a target like PacedVideoOutput/ OutputTinyGPU/OutputOpenCV that implements VideoOutput but not Print (the two are unrelated types - see VideoFrameMeter's own comment). Part of the base interface (unlike other concrete-class-specific extras) so code holding only a Demuxer& (e.g. VideoPlayer) can wire it to an arbitrary VideoOutput& without knowing the concrete container format - every current demuxer already implemented this identically before it was pulled up into the interface.

Implements Demuxer.

setSendWavHeader()

void setSendWavHeader ( bool  flag )

inlineoverridevirtual

Overrides the automatic decision of whether a synthetic WAV header (matching the parsed 'strf' audio format) is sent to the audio output before any audio payload. By default this is decided automatically from the parsed format: on whenever isWavFormat() of the parsed 'strf' format is true (PCM/ADPCM, i.e. audio that needs to go through a WAVDecoder), off otherwise (e.g. compressed formats with their own decoder that don't expect a WAV header). Call this to force it either way instead.

Implements Demuxer.

setupAudioInfo()

void setupAudioInfo ( )

inlineprotected

setupVideoInfo()

void setupVideoInfo ( )

inlineprotected

setValidationCallback()

void setValidationCallback ( bool(*)(DemuxerAVI &avi)  cb )

inline

Register a validation callback which is called after parsing just before playing the audio

toVideoFormat()

static VideoFormat toVideoFormat ( uint32_t  biCompression, uint16_t  biBitCount  )

inlinestaticprotected

Maps a 'strf' biCompression value (+ biBitCount, to disambiguate BI_BITFIELDS) to the corresponding VideoFormat. Covers what MuxerAVI writes plus a few common real-world FOURCC aliases seen in third-party AVI files.

tryParseChunk() [1/2]

ParseObject tryParseChunk ( )

inlineprotected

We parse a chunk and provide the FOURCC id and size: No content data is stored

tryParseChunk() [2/2]

ParseObject tryParseChunk ( const char *  id )

inlineprotected

We try to parse the indicated chunk and determine the size: No content data is stored

tryParseList() [1/2]

ParseObject tryParseList ( )

inlineprotected

We try to parse the actual state for any list.

tryParseList() [2/2]

ParseObject tryParseList ( const char *  id )

inlineprotected

videoInfo()

VideoInfo videoInfo ( )

inlineoverridevirtualinherited

Fulfills VideoInfoSource::videoInfo(), so any Demuxer can be passed directly to e.g. OutputOpenCV::setVideoInfoSource() - note the reported 'format' is the container's codec (e.g. H264), not necessarily what ends up written to a raw-picture VideoOutput/Print (that depends on whatever decoder sits between the demuxer and the output); consumers that care about the decoded format should still set it explicitly and rely on this only for width/height.

Implements VideoInfoSource.

videoSeconds()

int videoSeconds ( )

inline

Provide the length of the video in seconds.

write()

virtual size_t write ( const uint8_t *  data, size_t  len  )

inlineoverridevirtual

Implements AudioWriter.

writeBlocking()

void writeBlocking ( Print *  out, uint8_t *  data, size_t  len  )

inlineprotectedinherited

writeData()

void writeData ( )

inlineprotected

Member Data Documentation

audio_info

WAVFormatX audio_info

protected

content_types

Vector<StreamContentType> content_types

protected

current_pos

long current_pos = 0

protected

current_stream_data

ParseObject current_stream_data

protected

header_is_avi

bool header_is_avi = false

protected

id

int id

inherited

custom id to be used by application

info

AudioInfo info

protectedinherited

is_metadata_ready

bool is_metadata_ready = false

protected

is_mute

bool is_mute = false

protected

is_notify_active

bool is_notify_active = true

protectedinherited

is_parsing_active

bool is_parsing_active = true

protected

is_wav_header_sent

bool is_wav_header_sent = false

protected

main_header

AVIMainHeader main_header

protected

movi_end_pos

long movi_end_pos = 0

protected

notify_vector

Vector<AudioInfoSupport*> notify_vector

protectedinherited

object_stack

Stack<ParseObject> object_stack

protected

open_subchunk_len

long open_subchunk_len = 0

protected

p_output_audio

Print* p_output_audio = nullptr

protected

p_output_video

Print* p_output_video = nullptr

protected

p_output_video_video

VideoOutput* p_output_video_video = nullptr

protected

p_print

Print* p_print = nullptr

protectedinherited

parse_buffer

ParseBuffer parse_buffer

protected

parse_state

ParseState parse_state = ParseHeader

protected

riff_file_size

uint32_t riff_file_size = 0

protected

Total file size (bytes) declared by the RIFF header, normalized from its chunk_size (= file_size - 8) field; 0 if not yet parsed or the declared size looks like an unbounded/streamed placeholder.

send_wav_header

bool send_wav_header = false

protected

send_wav_header_explicit

bool send_wav_header_explicit = false

protected

spaces

Str spaces

protected

str

Str str

protected

stream_header

Vector<AVIStreamHeader> stream_header

protected

stream_header_idx

int stream_header_idx = -1

protected

validation_cb

bool(* validation_cb) (DemuxerAVI &avi) = nullptr

protected

video_accumulator

Vector<uint8_t> video_accumulator

protected

Accumulates one whole video chunk (one frame's worth of Annex-B NAL data) across however many writeData() calls it takes to stream the chunk in - see writeData()'s own comment for why: video decoders (e.g. H264Decoder/TinyH264) aren't guaranteed to handle a NAL unit arriving split across separate write() calls, so this only ever hands them one complete chunk per write() call, the same way DemuxerMP4 already does (it can, trivially, since MP4's sample table gives it each frame's exact size up front).

video_format

char video_format[5] = {0}

protected

video_info

BitmapInfoHeader video_info

protected

video_seconds

int video_seconds = 0

protected

---

The documentation for this class was generated from the following file:

• src/AudioTools/AudioCodecs/ContainerAVI.h