#include <avcodec.h>
Граф связей класса AVCodecContext:Подробное описание
main external API structure. New fields can be added to the end with minor version bumps. Removal, reordering and changes to existing fields require a major version bump. You can use AVOptions (av_opt* / av_set/get*()) to access these fields from user applications. The name string for AVOptions options matches the associated command line parameter name and can be found in libavcodec/options_table.h The AVOption/command line parameter names differ in some cases from the C structure field names for historic reasons or brevity. sizeof(AVCodecContext) must not be used outside libav*.
Данные класса
◆ av_class
| const AVClass* AVCodecContext::av_class |
◆ log_level_offset
◆ codec_type
| enum AVMediaType AVCodecContext::codec_type |
◆ codec
◆ codec_id
◆ codec_tag
| unsigned int AVCodecContext::codec_tag |
fourcc (LSB first, so "ABCD" -> ('D'<<24) + ('C'<<16) + ('B'<<8) + 'A'). This is used to work around some encoder bugs. A demuxer should set this to what is stored in the field used to identify the codec. If there are multiple such fields in a container then the demuxer should choose the one which maximizes the information about the used codec. If the codec tag field in a container is larger than 32 bits then the demuxer should remap the longer ID to 32 bits with a table or other structure. Alternatively a new extra_codec_tag + size could be added but for this a clear advantage must be demonstrated first.
- encoding: Set by user, if not then the default based on codec_id will be used.
- decoding: Set by user, will be converted to uppercase by libavcodec during init.
◆ priv_data
◆ internal
| struct AVCodecInternal* AVCodecContext::internal |
◆ opaque
| void* AVCodecContext::opaque |
◆ bit_rate
| int64_t AVCodecContext::bit_rate |
◆ bit_rate_tolerance
| int AVCodecContext::bit_rate_tolerance |
◆ global_quality
| int AVCodecContext::global_quality |
◆ compression_level
| int AVCodecContext::compression_level |
◆ flags
| int AVCodecContext::flags |
◆ flags2
| int AVCodecContext::flags2 |
◆ extradata
| uint8_t* AVCodecContext::extradata |
some codecs need / can use extradata like Huffman tables. MJPEG: Huffman tables rv10: additional flags MPEG-4: global headers (they can be in the bitstream or here) The allocated memory should be AV_INPUT_BUFFER_PADDING_SIZE bytes larger than extradata_size to avoid problems if it is read with the bitstream reader. The bytewise contents of extradata must not depend on the architecture or CPU endianness. Must be allocated with the av_malloc() family of functions.
- encoding: Set/allocated/freed by libavcodec.
- decoding: Set/allocated/freed by user.
◆ extradata_size
◆ time_base
| AVRational AVCodecContext::time_base |
This is the fundamental unit of time (in seconds) in terms of which frame timestamps are represented. For fixed-fps content, timebase should be 1/framerate and timestamp increments should be identically 1. This often, but not always is the inverse of the frame rate or field rate for video. 1/time_base is not the average frame rate if the frame rate is not constant.
Like containers, elementary streams also can store timestamps, 1/time_base is the unit in which these timestamps are specified. As example of such codec time base see ISO/IEC 14496-2:2001(E) vop_time_increment_resolution and fixed_vop_rate (fixed_vop_rate == 0 implies that it is different from the framerate)
- encoding: MUST be set by user.
- decoding: the use of this field for decoding is deprecated. Use framerate instead.
◆ ticks_per_frame
| int AVCodecContext::ticks_per_frame |
For some codecs, the time base is closer to the field rate than the frame rate. Most notably, H.264 and MPEG-2 specify time_base as half of frame duration if no telecine is used ...
Set to time_base ticks per frame. Default 1, e.g., H.264/MPEG-2 set it to 2.
◆ delay
| int AVCodecContext::delay |
Codec delay.
Encoding: Number of frames delay there will be from the encoder input to the decoder output. (we assume the decoder matches the spec) Decoding: Number of frames delay in addition to what a standard decoder as specified in the spec would produce.
Video: Number of frames the decoded output will be delayed relative to the encoded input.
Audio: For encoding, this field is unused (see initial_padding).
For decoding, this is the number of samples the decoder needs to output before the decoder's output is valid. When seeking, you should start decoding this many samples prior to your desired seek point.
- encoding: Set by libavcodec.
- decoding: Set by libavcodec.
◆ width
| int AVCodecContext::width |
picture width / height.
- Заметки
- Those fields may not match the values of the last AVFrame output by avcodec_decode_video2 due frame reordering.
- encoding: MUST be set by user.
- decoding: May be set by the user before opening the decoder if known e.g. from the container. Some decoders will require the dimensions to be set by the caller. During decoding, the decoder may overwrite those values as required while parsing the data.
См. определение в файле avcodec.h строка 1738
Используется в AVVideoStream::open().
◆ height
| int AVCodecContext::height |
См. определение в файле avcodec.h строка 1738
Используется в AVVideoStream::open().
◆ coded_width
| int AVCodecContext::coded_width |
Bitstream width / height, may be different from width/height e.g. when the decoded frame is cropped before being output or lowres is enabled.
- Заметки
- Those field may not match the value of the last AVFrame output by avcodec_receive_frame() due frame reordering.
- encoding: unused
- decoding: May be set by the user before opening the decoder if known e.g. from the container. During decoding, the decoder may overwrite those values as required while parsing the data.
◆ coded_height
◆ gop_size
| int AVCodecContext::gop_size |
◆ pix_fmt
| enum AVPixelFormat AVCodecContext::pix_fmt |
Pixel format, see AV_PIX_FMT_xxx. May be set by the demuxer if known from headers. May be overridden by the decoder if it knows better.
- Заметки
- This field may not match the value of the last AVFrame output by avcodec_receive_frame() due frame reordering.
- encoding: Set by user.
- decoding: Set by user if known, overridden by libavcodec while parsing the data.
См. определение в файле avcodec.h строка 1775
Используется в AVVideoStream::open().
◆ draw_horiz_band
| void(* AVCodecContext::draw_horiz_band) (struct AVCodecContext *s, const AVFrame *src, int offset[AV_NUM_DATA_POINTERS], int y, int type, int height) |
If non NULL, 'draw_horiz_band' is called by the libavcodec decoder to draw a horizontal band. It improves cache usage. Not all codecs can do that. You must check the codec capabilities beforehand. When multithreading is used, it may be called from multiple threads at the same time; threads might draw different parts of the same AVFrame, or multiple AVFrames, and there is no guarantee that slices will be drawn in order. The function is also used by hardware acceleration APIs. It is called at least once during frame decoding to pass the data needed for hardware render. In that mode instead of pixel data, AVFrame points to a structure specific to the acceleration API. The application reads the structure and can change some fields to indicate progress or mark state.
- encoding: unused
- decoding: Set by user.
- Аргументы
-
height the height of the slice y the y position of the slice type 1->top field, 2->bottom field, 3->frame offset offset into the AVFrame.data from which the slice should be read
◆ get_format
| enum AVPixelFormat(* AVCodecContext::get_format) (struct AVCodecContext *s, const enum AVPixelFormat *fmt) |
callback to negotiate the pixelFormat
- Аргументы
-
fmt is the list of formats which are supported by the codec, it is terminated by -1 as 0 is a valid format, the formats are ordered by quality. The first is always the native one.
- Заметки
- The callback may be called again immediately if initialization for the selected (hardware-accelerated) pixel format failed.
- Предупреждения
- Behavior is undefined if the callback returns a value not in the fmt list of formats.
- Возвращает
- the chosen format
- encoding: unused
- decoding: Set by user, if not set the native format will be chosen.
◆ max_b_frames
| int AVCodecContext::max_b_frames |
◆ b_quant_factor
| float AVCodecContext::b_quant_factor |
◆ b_frame_strategy
| attribute_deprecated int AVCodecContext::b_frame_strategy |
◆ b_quant_offset
| float AVCodecContext::b_quant_offset |
◆ has_b_frames
| int AVCodecContext::has_b_frames |
◆ mpeg_quant
| attribute_deprecated int AVCodecContext::mpeg_quant |
◆ i_quant_factor
| float AVCodecContext::i_quant_factor |
◆ i_quant_offset
| float AVCodecContext::i_quant_offset |
◆ lumi_masking
| float AVCodecContext::lumi_masking |
◆ temporal_cplx_masking
| float AVCodecContext::temporal_cplx_masking |
◆ spatial_cplx_masking
| float AVCodecContext::spatial_cplx_masking |
◆ p_masking
| float AVCodecContext::p_masking |
◆ dark_masking
| float AVCodecContext::dark_masking |
◆ slice_count
| int AVCodecContext::slice_count |
◆ prediction_method
| attribute_deprecated int AVCodecContext::prediction_method |
◆ slice_offset
| int* AVCodecContext::slice_offset |
◆ sample_aspect_ratio
| AVRational AVCodecContext::sample_aspect_ratio |
◆ me_cmp
| int AVCodecContext::me_cmp |
◆ me_sub_cmp
| int AVCodecContext::me_sub_cmp |
◆ mb_cmp
| int AVCodecContext::mb_cmp |
◆ ildct_cmp
| int AVCodecContext::ildct_cmp |
◆ dia_size
| int AVCodecContext::dia_size |
◆ last_predictor_count
| int AVCodecContext::last_predictor_count |
◆ pre_me
| attribute_deprecated int AVCodecContext::pre_me |
◆ me_pre_cmp
| int AVCodecContext::me_pre_cmp |
◆ pre_dia_size
| int AVCodecContext::pre_dia_size |
◆ me_subpel_quality
| int AVCodecContext::me_subpel_quality |
◆ me_range
| int AVCodecContext::me_range |
◆ slice_flags
| int AVCodecContext::slice_flags |
◆ mb_decision
| int AVCodecContext::mb_decision |
◆ intra_matrix
| uint16_t* AVCodecContext::intra_matrix |
custom intra quantization matrix Must be allocated with the av_malloc() family of functions, and will be freed in avcodec_free_context().
- encoding: Set/allocated by user, freed by libavcodec. Can be NULL.
- decoding: Set/allocated/freed by libavcodec.
◆ inter_matrix
| uint16_t* AVCodecContext::inter_matrix |
custom inter quantization matrix Must be allocated with the av_malloc() family of functions, and will be freed in avcodec_free_context().
- encoding: Set/allocated by user, freed by libavcodec. Can be NULL.
- decoding: Set/allocated/freed by libavcodec.
◆ scenechange_threshold
| attribute_deprecated int AVCodecContext::scenechange_threshold |
◆ noise_reduction
| attribute_deprecated int AVCodecContext::noise_reduction |
◆ intra_dc_precision
| int AVCodecContext::intra_dc_precision |
◆ skip_top
| int AVCodecContext::skip_top |
◆ skip_bottom
| int AVCodecContext::skip_bottom |
◆ mb_lmin
| int AVCodecContext::mb_lmin |
◆ mb_lmax
| int AVCodecContext::mb_lmax |
◆ me_penalty_compensation
| attribute_deprecated int AVCodecContext::me_penalty_compensation |
◆ bidir_refine
| int AVCodecContext::bidir_refine |
◆ brd_scale
| attribute_deprecated int AVCodecContext::brd_scale |
◆ keyint_min
| int AVCodecContext::keyint_min |
◆ refs
| int AVCodecContext::refs |
◆ chromaoffset
| attribute_deprecated int AVCodecContext::chromaoffset |
◆ mv0_threshold
| int AVCodecContext::mv0_threshold |
◆ b_sensitivity
| attribute_deprecated int AVCodecContext::b_sensitivity |
◆ color_primaries
| enum AVColorPrimaries AVCodecContext::color_primaries |
◆ color_trc
| enum AVColorTransferCharacteristic AVCodecContext::color_trc |
◆ colorspace
| enum AVColorSpace AVCodecContext::colorspace |
◆ color_range
| enum AVColorRange AVCodecContext::color_range |
◆ chroma_sample_location
| enum AVChromaLocation AVCodecContext::chroma_sample_location |
◆ slices
| int AVCodecContext::slices |
◆ field_order
| enum AVFieldOrder AVCodecContext::field_order |
◆ sample_rate
| int AVCodecContext::sample_rate |
samples per second
См. определение в файле avcodec.h строка 2225
Используется в AudioBaseDataSource::GetSampleRate(), Movie::Load(), AVAudioStream::open() и AudioBaseDataSource::Open().
◆ channels
| int AVCodecContext::channels |
number of audio channels
См. определение в файле avcodec.h строка 2226
Используется в AudioBaseDataSource::GetChannelCount() и AudioBaseDataSource::GetNextBuffer().
◆ sample_fmt
| enum AVSampleFormat AVCodecContext::sample_fmt |
sample format
audio sample format
- encoding: Set by user.
- decoding: Set by libavcodec.
См. определение в файле avcodec.h строка 2233
Используется в AVAudioStream::open() и AudioBaseDataSource::Open().
◆ frame_size
| int AVCodecContext::frame_size |
Number of samples per channel in an audio frame.
- encoding: set by libavcodec in avcodec_open2(). Each submitted frame except the last must contain exactly frame_size samples per channel. May be 0 when the codec has AV_CODEC_CAP_VARIABLE_FRAME_SIZE set, then the frame size is not restricted.
- decoding: may be set by some decoders to indicate constant frame size
◆ frame_number
| int AVCodecContext::frame_number |
◆ block_align
| int AVCodecContext::block_align |
◆ cutoff
| int AVCodecContext::cutoff |
◆ channel_layout
| uint64_t AVCodecContext::channel_layout |
Audio channel layout.
- encoding: set by user.
- decoding: set by user, may be overwritten by libavcodec.
См. определение в файле avcodec.h строка 2276
Используется в AVAudioStream::open() и AudioBaseDataSource::Open().
◆ request_channel_layout
| uint64_t AVCodecContext::request_channel_layout |
◆ audio_service_type
| enum AVAudioServiceType AVCodecContext::audio_service_type |
◆ request_sample_fmt
| enum AVSampleFormat AVCodecContext::request_sample_fmt |
◆ get_buffer2
| int(* AVCodecContext::get_buffer2) (struct AVCodecContext *s, AVFrame *frame, int flags) |
This callback is called at the beginning of each frame to get data buffer(s) for it. There may be one contiguous buffer for all the data or there may be a buffer per each data plane or anything in between. What this means is, you may set however many entries in buf[] you feel necessary. Each buffer must be reference-counted using the AVBuffer API (see description of buf[] below).
The following fields will be set in the frame before this callback is called:
- format
- width, height (video only)
- sample_rate, channel_layout, nb_samples (audio only) Their values may differ from the corresponding values in AVCodecContext. This callback must use the frame values, not the codec context values, to calculate the required buffer size.
This callback must fill the following fields in the frame:
- data[]
- linesize[]
- extended_data:
- if the data is planar audio with more than 8 channels, then this callback must allocate and fill extended_data to contain all pointers to all data planes. data[] must hold as many pointers as it can. extended_data must be allocated with av_malloc() and will be freed in av_frame_unref().
- otherwise extended_data must point to data
- buf[] must contain one or more pointers to AVBufferRef structures. Each of the frame's data and extended_data pointers must be contained in these. That is, one AVBufferRef for each allocated chunk of memory, not necessarily one AVBufferRef per data[] entry. See: av_buffer_create(), av_buffer_alloc(), and av_buffer_ref().
- extended_buf and nb_extended_buf must be allocated with av_malloc() by this callback and filled with the extra buffers if there are more buffers than buf[] can hold. extended_buf will be freed in av_frame_unref().
If AV_CODEC_CAP_DR1 is not set then get_buffer2() must call avcodec_default_get_buffer2() instead of providing buffers allocated by some other means.
Each data plane must be aligned to the maximum required by the target CPU.
- См. также
- avcodec_default_get_buffer2()
Video:
If AV_GET_BUFFER_FLAG_REF is set in flags then the frame may be reused (read and/or written to if it is writable) later by libavcodec.
avcodec_align_dimensions2() should be used to find the required width and height, as they normally need to be rounded up to the next multiple of 16.
Some decoders do not support linesizes changing between frames.
If frame multithreading is used and thread_safe_callbacks is set, this callback may be called from a different thread, but not from more than one at once. Does not need to be reentrant.
- См. также
- avcodec_align_dimensions2()
Audio:
Decoders request a buffer of a particular size by setting AVFrame.nb_samples prior to calling get_buffer2(). The decoder may, however, utilize only part of the buffer by setting AVFrame.nb_samples to a smaller value in the output frame.
As a convenience, av_samples_get_buffer_size() and av_samples_fill_arrays() in libavutil may be used by custom get_buffer2() functions to find the required data size and to fill data pointers and linesize. In AVFrame.linesize, only linesize[0] may be set for audio since all planes must be the same size.
- encoding: unused
- decoding: Set by libavcodec, user can override.
◆ refcounted_frames
| attribute_deprecated int AVCodecContext::refcounted_frames |
If non-zero, the decoded audio and video frames returned from avcodec_decode_video2() and avcodec_decode_audio4() are reference-counted and are valid indefinitely. The caller must free them with av_frame_unref() when they are not needed anymore. Otherwise, the decoded frames must not be freed by the caller and are only valid until the next decode call.
This is always automatically enabled if avcodec_receive_frame() is used.
- encoding: unused
- decoding: set by the caller before avcodec_open2().
◆ qcompress
| float AVCodecContext::qcompress |
◆ qblur
| float AVCodecContext::qblur |
◆ qmin
| int AVCodecContext::qmin |
◆ qmax
| int AVCodecContext::qmax |
◆ max_qdiff
| int AVCodecContext::max_qdiff |
◆ rc_buffer_size
| int AVCodecContext::rc_buffer_size |
◆ rc_override_count
| int AVCodecContext::rc_override_count |
ratecontrol override, see RcOverride
- encoding: Allocated/set/freed by user.
- decoding: unused
◆ rc_override
| RcOverride* AVCodecContext::rc_override |
◆ rc_max_rate
| int64_t AVCodecContext::rc_max_rate |
◆ rc_min_rate
| int64_t AVCodecContext::rc_min_rate |
◆ rc_max_available_vbv_use
| float AVCodecContext::rc_max_available_vbv_use |
◆ rc_min_vbv_overflow_use
| float AVCodecContext::rc_min_vbv_overflow_use |
◆ rc_initial_buffer_occupancy
| int AVCodecContext::rc_initial_buffer_occupancy |
◆ coder_type
| attribute_deprecated int AVCodecContext::coder_type |
◆ context_model
| attribute_deprecated int AVCodecContext::context_model |
◆ frame_skip_threshold
| attribute_deprecated int AVCodecContext::frame_skip_threshold |
◆ frame_skip_factor
| attribute_deprecated int AVCodecContext::frame_skip_factor |
◆ frame_skip_exp
| attribute_deprecated int AVCodecContext::frame_skip_exp |
◆ frame_skip_cmp
| attribute_deprecated int AVCodecContext::frame_skip_cmp |
◆ trellis
| int AVCodecContext::trellis |
◆ min_prediction_order
| attribute_deprecated int AVCodecContext::min_prediction_order |
◆ max_prediction_order
| attribute_deprecated int AVCodecContext::max_prediction_order |
◆ timecode_frame_start
| attribute_deprecated int64_t AVCodecContext::timecode_frame_start |
◆ rtp_callback
| attribute_deprecated void(* AVCodecContext::rtp_callback) (struct AVCodecContext *avctx, void *data, int size, int mb_nb) |
◆ rtp_payload_size
| attribute_deprecated int AVCodecContext::rtp_payload_size |
◆ mv_bits
◆ header_bits
◆ i_tex_bits
◆ p_tex_bits
◆ i_count
◆ p_count
◆ skip_count
◆ misc_bits
◆ frame_bits
| attribute_deprecated int AVCodecContext::frame_bits |
◆ stats_out
| char* AVCodecContext::stats_out |
◆ stats_in
| char* AVCodecContext::stats_in |
◆ workaround_bugs
| int AVCodecContext::workaround_bugs |
◆ strict_std_compliance
| int AVCodecContext::strict_std_compliance |
strictly follow the standard (MPEG-4, ...).
- encoding: Set by user.
- decoding: Set by user. Setting this to STRICT or higher means the encoder and decoder will generally do stupid things, whereas setting it to unofficial or lower will mean the encoder might produce output that is not supported by all spec-compliant decoders. Decoders don't differentiate between normal, unofficial and experimental (that is, they always try to decode things when they can) unless they are explicitly asked to behave stupidly (=strictly conform to the specs)
◆ error_concealment
| int AVCodecContext::error_concealment |
◆ debug
| int AVCodecContext::debug |
◆ debug_mv
| int AVCodecContext::debug_mv |
◆ err_recognition
| int AVCodecContext::err_recognition |
◆ reordered_opaque
| int64_t AVCodecContext::reordered_opaque |
opaque 64-bit number (generally a PTS) that will be reordered and output in AVFrame.reordered_opaque
- encoding: Set by libavcodec to the reordered_opaque of the input frame corresponding to the last returned packet. Only supported by encoders with the AV_CODEC_CAP_ENCODER_REORDERED_OPAQUE capability.
- decoding: Set by user.
◆ hwaccel
| const struct AVHWAccel* AVCodecContext::hwaccel |
◆ hwaccel_context
| void* AVCodecContext::hwaccel_context |
Hardware accelerator context. For some hardware accelerators, a global context needs to be provided by the user. In that case, this holds display-dependent data FFmpeg cannot instantiate itself. Please refer to the FFmpeg HW accelerator documentation to know how to fill this is. e.g. for VA API, this is a struct vaapi_context.
- encoding: unused
- decoding: Set by user
◆ error
| uint64_t AVCodecContext::error[AV_NUM_DATA_POINTERS] |
◆ dct_algo
| int AVCodecContext::dct_algo |
◆ idct_algo
| int AVCodecContext::idct_algo |
◆ bits_per_coded_sample
| int AVCodecContext::bits_per_coded_sample |
◆ bits_per_raw_sample
| int AVCodecContext::bits_per_raw_sample |
◆ lowres
| int AVCodecContext::lowres |
◆ coded_frame
| attribute_deprecated AVFrame* AVCodecContext::coded_frame |
◆ thread_count
| int AVCodecContext::thread_count |
◆ thread_type
| int AVCodecContext::thread_type |
Which multithreading methods to use. Use of FF_THREAD_FRAME will increase decoding delay by one frame per thread, so clients which cannot provide future frames should not use it.
- encoding: Set by user, otherwise the default is used.
- decoding: Set by user, otherwise the default is used.
◆ active_thread_type
| int AVCodecContext::active_thread_type |
◆ thread_safe_callbacks
| int AVCodecContext::thread_safe_callbacks |
Set by the client if its custom get_buffer() callback can be called synchronously from another thread, which allows faster multithreaded decoding. draw_horiz_band() will be called from other threads regardless of this setting. Ignored if the default get_buffer() is used.
- encoding: Set by user.
- decoding: Set by user.
◆ execute
| int(* AVCodecContext::execute) (struct AVCodecContext *c, int(*func)(struct AVCodecContext *c2, void *arg), void *arg2, int *ret, int count, int size) |
The codec may call this to execute several independent things. It will return only after finishing all tasks. The user may replace this with some multithreaded implementation, the default implementation will execute the parts serially.
- Аргументы
-
count the number of things to execute - encoding: Set by libavcodec, user can override.
- decoding: Set by libavcodec, user can override.
◆ execute2
| int(* AVCodecContext::execute2) (struct AVCodecContext *c, int(*func)(struct AVCodecContext *c2, void *arg, int jobnr, int threadnr), void *arg2, int *ret, int count) |
The codec may call this to execute several independent things. It will return only after finishing all tasks. The user may replace this with some multithreaded implementation, the default implementation will execute the parts serially. Also see avcodec_thread_init and e.g. the –enable-pthread configure option.
- Аргументы
-
c context passed also to func count the number of things to execute arg2 argument passed unchanged to func ret return values of executed functions, must have space for "count" values. May be NULL. func function that will be called count times, with jobnr from 0 to count-1. threadnr will be in the range 0 to c->thread_count-1 < MAX_THREADS and so that no two instances of func executing at the same time will have the same threadnr.
- Возвращает
- always 0 currently, but code should handle a future improvement where when any call to func returns < 0 no further calls to func may be done and < 0 is returned.
- encoding: Set by libavcodec, user can override.
- decoding: Set by libavcodec, user can override.
◆ nsse_weight
| int AVCodecContext::nsse_weight |
◆ profile
| int AVCodecContext::profile |
◆ level
| int AVCodecContext::level |
◆ skip_loop_filter
| enum AVDiscard AVCodecContext::skip_loop_filter |
◆ skip_idct
| enum AVDiscard AVCodecContext::skip_idct |
◆ skip_frame
| enum AVDiscard AVCodecContext::skip_frame |
◆ subtitle_header
| uint8_t* AVCodecContext::subtitle_header |
Header containing style information for text subtitles. For SUBTITLE_ASS subtitle type, it should contain the whole ASS [Script Info] and [V4+ Styles] section, plus the [Events] line and the Format line following. It shouldn't include any Dialogue line.
- encoding: Set/allocated/freed by user (before avcodec_open2())
- decoding: Set/allocated/freed by libavcodec (by avcodec_open2())
◆ subtitle_header_size
◆ vbv_delay
| attribute_deprecated uint64_t AVCodecContext::vbv_delay |
◆ side_data_only_packets
| attribute_deprecated int AVCodecContext::side_data_only_packets |
Encoding only and set by default. Allow encoders to output packets that do not contain any encoded data, only side data.
Some encoders need to output such packets, e.g. to update some stream parameters at the end of encoding.
- Уст.:
- this field disables the default behaviour and it is kept only for compatibility.
◆ initial_padding
| int AVCodecContext::initial_padding |
Audio only. The number of "priming" samples (padding) inserted by the encoder at the beginning of the audio. I.e. this number of leading decoded samples must be discarded by the caller to get the original audio without leading padding.
- decoding: unused
- encoding: Set by libavcodec. The timestamps on the output packets are adjusted by the encoder so that they always refer to the first sample of the data actually contained in the packet, including any added padding. E.g. if the timebase is 1/samplerate and the timestamp of the first input sample is 0, the timestamp of the first output packet will be -initial_padding.
◆ framerate
| AVRational AVCodecContext::framerate |
◆ sw_pix_fmt
| enum AVPixelFormat AVCodecContext::sw_pix_fmt |
Nominal unaccelerated pixel format, see AV_PIX_FMT_xxx.
- encoding: unused.
- decoding: Set by libavcodec before calling get_format()
◆ pkt_timebase
| AVRational AVCodecContext::pkt_timebase |
Timebase in which pkt_dts/pts and AVPacket.dts/pts are.
- encoding unused.
- decoding set by user.
◆ codec_descriptor
| const AVCodecDescriptor* AVCodecContext::codec_descriptor |
- encoding: unused.
- decoding: set by libavcodec.
◆ pts_correction_num_faulty_pts
| int64_t AVCodecContext::pts_correction_num_faulty_pts |
◆ pts_correction_num_faulty_dts
| int64_t AVCodecContext::pts_correction_num_faulty_dts |
◆ pts_correction_last_pts
| int64_t AVCodecContext::pts_correction_last_pts |
◆ pts_correction_last_dts
| int64_t AVCodecContext::pts_correction_last_dts |
◆ sub_charenc
| char* AVCodecContext::sub_charenc |
◆ sub_charenc_mode
| int AVCodecContext::sub_charenc_mode |
◆ skip_alpha
| int AVCodecContext::skip_alpha |
Skip processing alpha if supported by codec. Note that if the format uses pre-multiplied alpha (common with VP6, and recommended due to better video quality/compression) the image will look as if alpha-blended onto a black background. However for formats that do not use pre-multiplied alpha there might be serious artefacts (though e.g. libswscale currently assumes pre-multiplied alpha anyway).
- decoding: set by user
- encoding: unused
◆ seek_preroll
| int AVCodecContext::seek_preroll |
◆ chroma_intra_matrix
| uint16_t* AVCodecContext::chroma_intra_matrix |
◆ dump_separator
| uint8_t* AVCodecContext::dump_separator |
◆ codec_whitelist
| char* AVCodecContext::codec_whitelist |
◆ properties
| unsigned AVCodecContext::properties |
◆ coded_side_data
| AVPacketSideData* AVCodecContext::coded_side_data |
Additional data associated with the entire coded stream.
- decoding: unused
- encoding: may be set by libavcodec after avcodec_open2().
◆ nb_coded_side_data
◆ hw_frames_ctx
| AVBufferRef* AVCodecContext::hw_frames_ctx |
A reference to the AVHWFramesContext describing the input (for encoding) or output (decoding) frames. The reference is set by the caller and afterwards owned (and freed) by libavcodec - it should never be read by the caller after being set.
decoding: This field should be set by the caller from the get_format() callback. The previous reference (if any) will always be unreffed by libavcodec before the get_format() call.
If the default get_buffer2() is used with a hwaccel pixel format, then this AVHWFramesContext will be used for allocating the frame buffers.
encoding: For hardware encoders configured to use a hwaccel pixel format, this field should be set by the caller to a reference to the AVHWFramesContext describing input frames. AVHWFramesContext.format must be equal to AVCodecContext.pix_fmt.
This field should be set before avcodec_open2() is called.
◆ sub_text_format
| int AVCodecContext::sub_text_format |
Control the form of AVSubtitle.rects[N]->ass
- decoding: set by user
- encoding: unused
◆ trailing_padding
| int AVCodecContext::trailing_padding |
Audio only. The amount of padding (in samples) appended by the encoder to the end of the audio. I.e. this number of decoded samples must be discarded by the caller from the end of the stream to get the original audio without any trailing padding.
- decoding: unused
- encoding: unused
◆ max_pixels
| int64_t AVCodecContext::max_pixels |
◆ hw_device_ctx
| AVBufferRef* AVCodecContext::hw_device_ctx |
A reference to the AVHWDeviceContext describing the device which will be used by a hardware encoder/decoder. The reference is set by the caller and afterwards owned (and freed) by libavcodec.
This should be used if either the codec device does not require hardware frames or any that are used are to be allocated internally by libavcodec. If the user wishes to supply any of the frames used as encoder input or decoder output then hw_frames_ctx should be used instead. When hw_frames_ctx is set in get_format() for a decoder, this field will be ignored while decoding the associated stream segment, but may again be used on a following one after another get_format() call.
For both encoders and decoders this field should be set before avcodec_open2() is called and must not be written to thereafter.
Note that some decoders may require this field to be set initially in order to support hw_frames_ctx at all - in that case, all frames contexts used must be created on the same device.
◆ hwaccel_flags
| int AVCodecContext::hwaccel_flags |
Bit set of AV_HWACCEL_FLAG_* flags, which affect hardware accelerated decoding (if active).
- encoding: unused
- decoding: Set by user (either before avcodec_open2(), or in the AVCodecContext.get_format callback)
◆ apply_cropping
| int AVCodecContext::apply_cropping |
Video decoding only. Certain video codecs support cropping, meaning that only a sub-rectangle of the decoded frame is intended for display. This option controls how cropping is handled by libavcodec.
When set to 1 (the default), libavcodec will apply cropping internally. I.e. it will modify the output frame width/height fields and offset the data pointers (only by as much as possible while preserving alignment, or by the full amount if the AV_CODEC_FLAG_UNALIGNED flag is set) so that the frames output by the decoder refer only to the cropped area. The crop_* fields of the output frames will be zero.
When set to 0, the width/height fields of the output frames will be set to the coded dimensions and the crop_* fields will describe the cropping rectangle. Applying the cropping is left to the caller.
- Предупреждения
- When hardware acceleration with opaque output frames is used, libavcodec is unable to apply cropping from the top/left border.
- Заметки
- when this option is set to zero, the width/height fields of the AVCodecContext and output AVFrames have different meanings. The codec context fields store display dimensions (with the coded dimensions in coded_width/height), while the frame fields store the coded dimensions (with the display dimensions being determined by the crop_* fields).
◆ extra_hw_frames
◆ discard_damaged_percentage
| int AVCodecContext::discard_damaged_percentage |
Объявления и описания членов структуры находятся в файле:
- C:/git/world-of-might-and-magic/lib/win32/x86/ffmpeg-4.2.2/include/libavcodec/avcodec.h
