FFmpeg: Utility functions

If hwaccel is NULL, returns the first registered hardware accelerator, if hwaccel is non-NULL, returns the next registered hardware accelerator after hwaccel, or NULL if hwaccel is the last one.

int av_lockmgr_register (int(*cb)(void **mutex, enum AVLockOp op))

enum AVMediaType avcodec_get_type (enum AVCodecID codec_id)

Get the type of the given codec.

const char * avcodec_get_name (enum AVCodecID id)

Get the name of a codec.

int avcodec_is_open (AVCodecContext *s)

int av_codec_is_encoder (const AVCodec *codec)

int av_codec_is_decoder (const AVCodec *codec)

const AVCodecDescriptor * avcodec_descriptor_get (enum AVCodecID id)

const AVCodecDescriptor * avcodec_descriptor_next (const AVCodecDescriptor *prev)

Iterate over all codec descriptors known to libavcodec.

const AVCodecDescriptor * avcodec_descriptor_get_by_name (const char *name)

Detailed Description

Miscellaneous utility functions related to both encoding and decoding (or neither).

Enumeration Type Documentation

enum AVLockOp

Lock operation used by lockmgr.

Enumerator:: AV_LOCK_CREATE
Create a mutex.

AV_LOCK_OBTAIN
Lock the mutex.

AV_LOCK_RELEASE
Unlock the mutex.

AV_LOCK_DESTROY
Free mutex resources.

Definition at line 4992 of file avcodec.h.

Function Documentation

void avcodec_set_dimensions ( AVCodecContext * s,

int width,

int height

)

Definition at line 170 of file utils.c.

Referenced by apply_param_change(), av_mpeg4_decode_header(), avcodec_open2(), avpriv_dirac_parse_sequence_header(), avs_decode_init(), brpix_decode_frame(), cdxl_decode_frame(), cmv_process_header(), decode_frame(), decode_frame_headers(), decode_init(), dnxhd_decode_frame(), dvdsub_parse_extradata(), dvvideo_decode_frame(), execute_code(), ff_h263_decode_frame(), ff_ivi_decode_frame(), ff_mjpeg_decode_sof(), ff_rv34_decode_frame(), ff_vc1_decode_entry_point(), ff_vc1_decode_sequence_header(), flashsv_decode_frame(), gif_decode_frame(), h261_decode_frame(), h264_slice_header_init(), init_image(), libopenjpeg_decode_frame(), mpeg_decode_postinit(), mpegvideo_extract_headers(), mvc_decode_init(), parse_presentation_segment(), pcx_decode_frame(), process_frame_obj(), ptx_decode_frame(), rv20_decode_picture_header(), sunrast_decode_frame(), svq1_decode_frame(), tgq_decode_frame(), tgv_decode_frame(), theora_header(), tqi_decode_frame(), truemotion1_decode_header(), txd_decode_frame(), update_dimensions(), vp56_size_changed(), vp5_parse_header(), vp6_parse_header(), and vp8_decode().

size_t av_get_codec_tag_string ( char * buf,

size_t buf_size,

unsigned int codec_tag

)

Put a string representing the codec tag codec_tag in buf.

Parameters: buf_size size in bytes of buf

Returns: the length of the string that would have been generated if enough space had been available, excluding the trailing null

Definition at line 2019 of file utils.c.

Referenced by avcodec_string(), init_muxer(), main(), print_pix_fmt_fourccs(), and show_stream().

void avcodec_string ( char * buf,

int buf_size,

AVCodecContext * enc,

int encode

)

Definition at line 2039 of file utils.c.

Referenced by avformat_find_stream_info(), and dump_stream_format().

const char* av_get_profile_name ( const AVCodec * codec,

int profile

)

Return a name for the specified profile, if available.

Parameters: codec the codec that is searched for the given profile

profile the profile value for which a name is requested

Returns: A name for the profile if found, NULL otherwise.

Definition at line 2141 of file utils.c.

Referenced by avcodec_string(), and show_stream().

int avcodec_default_execute ( AVCodecContext * c,

int(*)(AVCodecContext *c2, void *arg2) func,

void * arg,

int * ret,

int count,

int size

)

Definition at line 629 of file utils.c.

Referenced by avcodec_get_context_defaults3(), and avcodec_thread_execute().

int avcodec_default_execute2 ( AVCodecContext * c,

int(*)(AVCodecContext *c2, void *arg2, int, int) func,

void * arg,

int * ret,

int count

)

Referenced by avcodec_get_context_defaults3().

int avcodec_fill_audio_frame ( AVFrame * frame,

int nb_channels,

enum AVSampleFormat sample_fmt,

const uint8_t * buf,

int buf_size,

int align

)

Fill AVFrame audio data and linesize pointers.

The buffer buf must be a preallocated buffer with a size big enough to contain the specified samples amount. The filled AVFrame data pointers will point to this buffer.

AVFrame extended_data channel pointers are allocated if necessary for planar audio.

Parameters: frame the AVFrame frame->nb_samples must be set prior to calling the function. This function fills in frame->data, frame->extended_data, frame->linesize[0].

nb_channels channel count

sample_fmt sample format

buf buffer to use for frame data

buf_size size of buffer

align plane size sample alignment (0 = default)

Returns: >=0 on success, negative error code on failure

Todo:: return the size in bytes required to store the samples in case of success, at the next libavutil bump

Examples:: doc/examples/decoding_encoding.c, and doc/examples/muxing.c.

Definition at line 308 of file utils.c.

Referenced by audio_encode_example(), audio_get_buffer(), pad_last_frame(), and write_audio_frame().

void avcodec_flush_buffers ( AVCodecContext * avctx )

Flush buffers, should be called when seeking or when switching to a different stream.

Definition at line 2177 of file utils.c.

Referenced by audio_decode_frame(), get_video_frame(), rewind_file(), subtitle_thread(), and video_thread().

void avcodec_default_free_buffers ( AVCodecContext * s )

Definition at line 2217 of file utils.c.

Referenced by avcodec_close(), ff_MPV_common_end(), and frame_thread_free().

int av_get_bits_per_sample ( enum AVCodecID codec_id )

Return codec bits per sample.

Parameters: [in] codec_id the codec

Returns: Number of bits per sample or zero if unknown for the given codec.

Definition at line 2302 of file utils.c.

Referenced by adpcm_encode_init(), aiff_write_header(), avformat_find_stream_info(), caf_write_header(), epaf_read_header(), ff_alsa_open(), ff_audio_interleave_init(), ff_mov_read_stsd_entries(), ff_pcm_read_seek(), ff_voc_get_packet(), g722_read_header(), get_aiff_header(), get_bit_rate(), gxf_packet(), iff_read_header(), init_muxer(), ircam_read_header(), mkv_write_tracks(), mov_get_codec_tag(), mov_write_audio_tag(), mov_write_header(), mxf_set_audio_pts(), mxf_write_generic_sound_common(), oma_read_header(), pcm_decode_frame(), pcm_decode_init(), pcm_encode_frame(), pcm_encode_init(), pcm_read_header(), pulse_read_header(), read_header(), rso_read_header(), and show_stream().

enum AVCodecID av_get_pcm_codec ( enum AVSampleFormat fmt,

int be

)

Return the PCM codec associated with a sample format.

Parameters: be endianness, 0 for little, 1 for big, -1 (or anything else) for native

Returns: AV_CODEC_ID_PCM_* or AV_CODEC_ID_NONE

Definition at line 2281 of file utils.c.

Referenced by lavfi_read_header().

int av_get_exact_bits_per_sample ( enum AVCodecID codec_id )

Return codec bits per sample.

Only return non-zero if the bits per sample is exactly correct, not an approximation.

Parameters: [in] codec_id the codec

Returns: Number of bits per sample or zero if unknown for the given codec.

Definition at line 2231 of file utils.c.

Referenced by av_get_audio_frame_duration(), and av_get_bits_per_sample().

int av_get_audio_frame_duration ( AVCodecContext * avctx,

int frame_bytes

)

Return audio frame duration.

Parameters: avctx codec context

frame_bytes size of the frame, or 0 if unknown

Returns: frame duration, in samples, if known. 0 if not able to determine.

Definition at line 2320 of file utils.c.

Referenced by build_frame_code(), do_streamcopy(), ff_get_audio_frame_size(), get_aiff_header(), rtp_send_ilbc(), and rtp_write_header().

void av_register_bitstream_filter ( AVBitStreamFilter * bsf )

Definition at line 33 of file bitstream_filter.c.

AVBitStreamFilterContext* av_bitstream_filter_init ( const char * name )

Definition at line 38 of file bitstream_filter.c.

Referenced by init(), new_output_stream(), and Stagefright_init().

int av_bitstream_filter_filter ( AVBitStreamFilterContext * bsfc,

AVCodecContext * avctx,

const char * args,

uint8_t ** poutbuf,

int * poutbuf_size,

const uint8_t * buf,

int buf_size,

int keyframe

)

Definition at line 61 of file bitstream_filter.c.

Referenced by decode(), init(), Stagefright_decode_frame(), and write_frame().

void av_bitstream_filter_close ( AVBitStreamFilterContext * bsf )

Definition at line 53 of file bitstream_filter.c.

Referenced by exit_program(), Stagefright_close(), Stagefright_init(), and uninit().

AVBitStreamFilter* av_bitstream_filter_next ( AVBitStreamFilter * f )

Definition at line 28 of file bitstream_filter.c.

Referenced by show_bsfs().

void* av_fast_realloc ( void * ptr,

unsigned int * size,

size_t min_size

)

Reallocate the given block if it is not large enough, otherwise do nothing.

See Also: av_realloc

Definition at line 57 of file utils.c.

Referenced by caf_write_packet(), commit_slices(), decode_frame(), decode_slice(), dirac_combine_frame(), ff_add_index_entry(), ff_af_queue_add(), ff_combine_frame(), ff_mms_asf_header_parser(), ff_subtitles_queue_insert(), ff_vaapi_alloc_slice(), ff_vdpau_add_data_chunk(), flac_fifo_read_wrap(), get_stats(), mkv_copy_packet(), mxg_update_cache(), read_frame(), shorten_decode_frame(), and spdif_header_eac3().

void av_fast_malloc ( void * ptr,

unsigned int * size,

size_t min_size

)

Allocate a buffer, reusing the given one if large enough.

Contrary to av_fast_realloc the current buffer contents might not be preserved and on error the old buffer is freed, thus no special handling to avoid memleaks is necessary.

Parameters: ptr pointer to pointer to already allocated buffer, overwritten with pointer to new buffer

size size of the buffer *ptr points to

min_size minimum size of *ptr buffer after returning, *ptr will be NULL and *size 0 if an error occurred.

Definition at line 90 of file utils.c.

Referenced by allocate_buffers(), ape_decode_frame(), codec_reinit(), dca_decode_frame(), decode_8(), decode_frame(), decode_i_frame(), decode_p_frame(), ff_h263_decode_frame(), ff_id3v2_parse(), ff_mpeg_update_thread_context(), gif_read_header1(), gif_read_image(), ljpeg_decode_rgb_scan(), mp_decode_frame(), parse_picture_segment(), pmp_packet(), reconfigure_at_keyframe(), spdif_header_dts4(), spdif_write_packet(), submit_packet(), svq3_decode_frame(), tak_decode_frame(), truemotion1_decode_header(), truemotion1_decode_init(), update_md5_sum(), and utvideo_encode_frame().

void av_fast_padded_malloc ( void * ptr,

unsigned int * size,

size_t min_size

)

Same behaviour av_fast_malloc but the buffer has additional FF_INPUT_BUFFER_PADDING_SIZE at the end which will will always be 0.

In addition the whole buffer will initially and after resizes be 0-initialized so that no uninitialized data will ever appear.

Definition at line 95 of file utils.c.

Referenced by cdxl_decode_frame(), cllc_decode_frame(), decode_frame(), ebml_read_binary(), encode_frame(), ff_alloc_packet2(), ff_h264_decode_nal(), ff_mjpeg_find_marker(), init_buffers(), mimic_decode_frame(), mpc7_decode_frame(), tiff_unpack_strip(), and tqi_decode_frame().

void av_fast_padded_mallocz ( void * ptr,

unsigned int * size,

size_t min_size

)

Same behaviour av_fast_padded_malloc except that buffer will always be 0-initialized after call.

Definition at line 107 of file utils.c.

Referenced by encode_frame().

unsigned int av_xiphlacing ( unsigned char * s,

unsigned int v

)

Encode extradata length to a buffer.

Used by xiph codecs.

Parameters: s buffer to write to; must be at least (v/255+1) bytes long

v size of extradata in bytes

Returns: number of bytes written to the buffer.

Definition at line 2486 of file utils.c.

Referenced by fixup_vorbis_headers(), oggvorbis_encode_init(), parse_packed_headers(), and put_main_header().

void av_log_missing_feature ( void * avc,

const char * feature,

int want_sample

)

Log a generic warning message about a missing feature.

This function is intended to be used internally by FFmpeg (libavcodec, libavformat, etc.) only, and would normally not be used by applications.

Parameters: [in] avc a pointer to an arbitrary struct of which the first field is a pointer to an AVClass struct

[in] feature string containing the name of the missing feature

[in] want_sample indicates if samples are wanted which exhibit this feature. If want_sample is non-zero, additional verbage will be added to the log message which tells the user how to report samples to the development mailing list.

Definition at line 2507 of file utils.c.

Referenced by aac_adtstoasc_filter(), amr_decode_fix_avctx(), amrnb_decode_frame(), amrnb_decode_init(), amrwb_decode_frame(), amrwb_decode_init(), decode_audio_block(), decode_frame(), decode_frame_header(), decode_ga_specific_config(), decode_ics(), decode_init(), decode_packet(), decode_seq_header(), decode_subframe(), epaf_read_header(), ff_eac3_parse_header(), ff_mjpeg_decode_sof(), ff_spdif_read_packet(), ff_vc1_parse_frame_header_adv(), flashsv_decode_frame(), h264_set_parameter_from_sps(), latm_decode_audio_specific_config(), mpc8_decode_init(), ogg_replace_stream(), parse_adts_frame_header(), parse_fmtp(), parse_MP4SLDescrTag(), qt_rtp_parse_packet(), read_sbr_extension(), read_stream_mux_config(), rv10_decode_init(), skeleton_header(), smc_decode_stream(), spdif_get_offset_and_codec(), synth_superframe(), tm2_read_header(), tta_decode_init(), vp6_parse_header(), and write_header().

void av_log_ask_for_sample ( void * avc,

const char * msg,

...

)

Log a generic warning message asking for a sample.

This function is intended to be used internally by FFmpeg (libavcodec, libavformat, etc.) only, and would normally not be used by applications.

Parameters: [in] avc a pointer to an arbitrary struct of which the first field is a pointer to an AVClass struct

[in] msg string containing an optional message, or NULL if no message

Referenced by alac_decode_init(), ape_decode_init(), ast_read_header(), atrac1_decode_init(), av_log_missing_feature(), avpriv_adx_decode_header(), avr_read_header(), cdxl_decode_frame(), cinepak_decode(), cook_decode_init(), dca_decode_frame(), dca_exss_parse_header(), dca_parse_frame_header(), dca_subframe_header(), decode_band_hdr(), decode_bytes(), decode_channel_transform(), decode_frame(), decode_frame_headers(), decode_init(), decode_mvc2(), decode_nop(), decode_scalefactors(), decode_sgirle8(), decode_slice_header(), decode_subframe(), decode_wmv9(), determine_bitrate(), ea_read_packet(), execute_code(), ff_compute_band_indexes(), ff_mjpeg_decode_sof(), ff_parse_mpeg2_descriptor(), ff_spdif_read_packet(), get_packet_header(), iff_read_header(), imc_decode_block(), imc_decode_init(), lvf_read_header(), mov_read_mdhd(), mpc7_decode_init(), mtv_read_header(), mv_read_header(), mxf_read_packet_old(), mxf_read_primer_pack(), nist_read_header(), oma_read_header(), paf_vid_decode(), parse_setup_header(), parse_video_var(), pmp_packet(), process_audio_header_eacs(), process_audio_header_elements(), process_ea_header(), process_frame_obj(), ptx_decode_frame(), ra288_decode_init(), read_block_data(), read_frame(), read_header(), read_major_sync(), read_restart_header(), read_table(), rso_read_header(), save_bits(), smjpeg_read_header(), spdif_header_dts(), spdif_header_truehd(), sunrast_decode_frame(), truemotion1_decode_header(), truespeech_decode_init(), unsupported(), vcr1_decode_init(), wsaud_read_header(), xa_decode(), xmv_read_header(), xwd_decode_frame(), xwma_read_header(), and zero12v_decode_init().

void void av_register_hwaccel ( AVHWAccel * hwaccel )

Definition at line 2534 of file utils.c.

AVHWAccel* av_hwaccel_next ( AVHWAccel * hwaccel )

If hwaccel is NULL, returns the first registered hardware accelerator, if hwaccel is non-NULL, returns the next registered hardware accelerator after hwaccel, or NULL if hwaccel is the last one.

Definition at line 2543 of file utils.c.

Referenced by ff_find_hwaccel().

int av_lockmgr_register ( int(*)(void **mutex, enum AVLockOp op) cb )

mutex points to a (void *) where the lockmgr should store/get a pointer to a user allocated mutex. It's NULL upon AV_LOCK_CREATE and != NULL for all other ops.

Parameters: cb User defined callback. Note: FFmpeg may invoke calls to this callback during the call to av_lockmgr_register(). Thus, the application must be prepared to handle that. If cb is set to NULL the lockmgr will be unregistered. Also note that during unregistration the previously registered lockmgr callback may also be invoked.

Definition at line 2559 of file utils.c.

Referenced by do_exit(), and main().

enum AVMediaType avcodec_get_type ( enum AVCodecID codec_id )

Get the type of the given codec.

Definition at line 2668 of file utils.c.

Referenced by mkv_query_codec().

const char* avcodec_get_name ( enum AVCodecID id )

Get the name of a codec.