libspeex Speex audio encoder More...
#include <speex/speex.h>
#include <speex/speex_header.h>
#include <speex/speex_stereo.h>
#include "libavutil/mathematics.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "internal.h"
Go to the source code of this file.
Data Structures | |
struct | LibSpeexEncContext |
Macros | |
#define | OFFSET(x) offsetof(LibSpeexEncContext, x) |
#define | AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM |
Functions | |
static av_cold void | print_enc_params (AVCodecContext *avctx, LibSpeexEncContext *s) |
static av_cold int | encode_init (AVCodecContext *avctx) |
static int | encode_frame (AVCodecContext *avctx, uint8_t *frame, int buf_size, void *data) |
static av_cold int | encode_close (AVCodecContext *avctx) |
Variables | |
static const AVOption | options [] |
class { | |
class_name = "libspeex" | |
item_name = av_default_item_name | |
option = options | |
version = LIBAVUTIL_VERSION_INT | |
}; | |
static const AVCodecDefault | defaults [] |
AVCodec | ff_libspeex_encoder |
libspeex Speex audio encoder
Usage Guide This explains the values that need to be set prior to initialization in order to control various encoding parameters.
Channels Speex only supports mono or stereo, so avctx->channels must be set to 1 or 2.
Sample Rate / Encoding Mode Speex has 3 modes, each of which uses a specific sample rate. narrowband : 8 kHz wideband : 16 kHz ultra-wideband : 32 kHz avctx->sample_rate must be set to one of these 3 values. This will be used to set the encoding mode.
Rate Control VBR mode is turned on by setting CODEC_FLAG_QSCALE in avctx->flags. avctx->global_quality is used to set the encoding quality. For CBR mode, avctx->bit_rate can be used to set the constant bitrate. Alternatively, the 'cbr_quality' option can be set from 0 to 10 to set a constant bitrate based on quality. For ABR mode, set avctx->bit_rate and set the 'abr' option to 1. Approx. Bitrate Range: narrowband : 2400 - 25600 bps wideband : 4000 - 43200 bps ultra-wideband : 4400 - 45200 bps
Complexity Encoding complexity is controlled by setting avctx->compression_level. The valid range is 0 to 10. A higher setting gives generally better quality at the expense of encoding speed. This does not affect the bit rate.
Frames-per-Packet The encoder defaults to using 1 frame-per-packet. However, it is sometimes desirable to use multiple frames-per-packet to reduce the amount of container overhead. This can be done by setting the 'frames_per_packet' option to a value 1 to 8.
Definition in file libspeexenc.c.
#define AE AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM |
Definition at line 292 of file libspeexenc.c.
#define OFFSET | ( | x | ) | offsetof(LibSpeexEncContext, x) |
Definition at line 291 of file libspeexenc.c.
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Definition at line 278 of file libspeexenc.c.
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Definition at line 234 of file libspeexenc.c.
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Definition at line 122 of file libspeexenc.c.
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Definition at line 90 of file libspeexenc.c.
Referenced by encode_init().
const { ... } |
class_name = "libspeex" |
Definition at line 301 of file libspeexenc.c.
Referenced by av_opt_show2().
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Definition at line 307 of file libspeexenc.c.
AVCodec ff_libspeex_encoder |
Definition at line 313 of file libspeexenc.c.
item_name = av_default_item_name |
Definition at line 302 of file libspeexenc.c.
option = options |
Definition at line 303 of file libspeexenc.c.
Referenced by pp_get_mode_by_name_and_quality().
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Definition at line 293 of file libspeexenc.c.
version = LIBAVUTIL_VERSION_INT |
Definition at line 304 of file libspeexenc.c.
Referenced by adpcm_compress_trellis(), aiff_read_header(), celt_header(), decode_frame(), decode_frame_header(), decode_init(), ff_mov_read_stsd_entries(), mov_read_chan(), mov_read_chpl(), mov_read_elst(), mov_read_mdhd(), mov_read_mvhd(), mov_read_tkhd(), mov_write_audio_tag(), mov_write_edts_tag(), mov_write_mdhd_tag(), mov_write_mvhd_tag(), mov_write_tkhd_tag(), mxf_write_identification(), read_header(), rm_read_audio_stream_info(), smjpeg_read_header(), spdif_header_mpeg(), swf_write_header(), txd_decode_frame(), vble_decode_frame(), voc_probe(), and voc_write_header().