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FFmpeg
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WMA Voice decoding context. More...
Public Attributes | |
Global values specified in the stream header / extradata or used all over. | |
| GetBitContext | gb |
| packet bitreader. More... | |
| int8_t | vbm_tree [25] |
| converts VLC codes to frame type | |
| int | spillover_bitsize |
| number of bits used to specify spillover_nbits in the packet header = ceil(log2(ctx->block_align << 3)) | |
| int | history_nsamples |
| number of samples in history for signal prediction (through ACB) | |
| int | do_apf |
| whether to apply the averaged projection filter (APF) | |
| int | denoise_strength |
| strength of denoising in Wiener filter [0-11] | |
| int | denoise_tilt_corr |
| Whether to apply tilt correction to the Wiener filter coefficients (postfilter) | |
| int | dc_level |
| Predicted amount of DC noise, based on which a DC removal filter is used. | |
| int | lsps |
| number of LSPs per frame [10 or 16] | |
| int | lsp_q_mode |
| defines quantizer defaults [0, 1] | |
| int | lsp_def_mode |
| defines different sets of LSP defaults [0, 1] | |
| int | min_pitch_val |
| base value for pitch parsing code | |
| int | max_pitch_val |
| max value + 1 for pitch parsing | |
| int | pitch_nbits |
| number of bits used to specify the pitch value in the frame header | |
| int | block_pitch_nbits |
| number of bits used to specify the first block's pitch value | |
| int | block_pitch_range |
| range of the block pitch | |
| int | block_delta_pitch_nbits |
| number of bits used to specify the delta pitch between this and the last block's pitch value, used in all but first block | |
| int | block_delta_pitch_hrange |
| 1/2 range of the delta (full range is from -this to +this-1) | |
| uint16_t | block_conv_table [4] |
| boundaries for block pitch unit/scale conversion | |
Packet values specified in the packet header or related to a packet. | |
A packet is considered to be a single unit of data provided to this decoder by the demuxer. | |
| int | spillover_nbits |
| number of bits of the previous packet's last superframe preceding this packet's first full superframe (useful for re-synchronization also) | |
| int | has_residual_lsps |
| if set, superframes contain one set of LSPs that cover all frames, encoded as independent and residual LSPs; if not set, each frame contains its own, fully independent, LSPs | |
| int | skip_bits_next |
| number of bits to skip at the next call to wmavoice_decode_packet() (since they're part of the previous superframe) | |
| uint8_t | sframe_cache [SFRAME_CACHE_MAXSIZE+AV_INPUT_BUFFER_PADDING_SIZE] |
| cache for superframe data split over multiple packets | |
| int | sframe_cache_size |
| set to >0 if we have data from an (incomplete) superframe from a previous packet that spilled over in the current packet; specifies the amount of bits in sframe_cache | |
| PutBitContext | pb |
| bitstream writer for sframe_cache | |
Frame and superframe values | |
Superframe and frame data - these can change from frame to frame, although some of them do in that case serve as a cache / history for the next frame or superframe. | |
| double | prev_lsps [MAX_LSPS] |
| LSPs of the last frame of the previous superframe. | |
| int | last_pitch_val |
| pitch value of the previous frame | |
| int | last_acb_type |
| frame type [0-2] of the previous frame | |
| int | pitch_diff_sh16 |
| ((cur_pitch_val - last_pitch_val) << 16) / MAX_FRAMESIZE | |
| float | silence_gain |
| set for use in blocks if ACB_TYPE_NONE | |
| int | aw_idx_is_ext |
| whether the AW index was encoded in 8 bits (instead of 6) | |
| int | aw_pulse_range |
| the range over which aw_pulse_set1() can apply the pulse, relative to the value in aw_first_pulse_off. More... | |
| int | aw_n_pulses [2] |
| number of AW-pulses in each block; note that this number can be negative (in which case it basically means "zero") | |
| int | aw_first_pulse_off [2] |
| index of first sample to which to apply AW-pulses, or -0xff if unset | |
| int | aw_next_pulse_off_cache |
| the position (relative to start of the second block) at which pulses should start to be positioned, serves as a cache for pitch-adaptive window pulses between blocks | |
| int | frame_cntr |
| current frame index [0 - 0xFFFE]; is only used for comfort noise in pRNG() | |
| int | nb_superframes |
| number of superframes in current packet | |
| float | gain_pred_err [6] |
| cache for gain prediction | |
| float | excitation_history [MAX_SIGNAL_HISTORY] |
| cache of the signal of previous superframes, used as a history for signal generation | |
| float | synth_history [MAX_LSPS] |
| see excitation_history | |
Postfilter values | |
Variables used for postfilter implementation, mostly history for smoothing and so on, and context variables for FFT/iFFT. | |
| RDFTContext | rdft |
| RDFTContext | irdft |
| contexts for FFT-calculation in the postfilter (for denoise filter) | |
| DCTContext | dct |
| DCTContext | dst |
| contexts for phase shift (in Hilbert transform, part of postfilter) | |
| float | sin [511] |
| float | cos [511] |
| 8-bit cosine/sine windows over [-pi,pi] range | |
| float | postfilter_agc |
| gain control memory, used in adaptive_gain_control() | |
| float | dcf_mem [2] |
| DC filter history. | |
| float | zero_exc_pf [MAX_SIGNAL_HISTORY+MAX_SFRAMESIZE] |
| zero filter output (i.e. More... | |
| float | denoise_filter_cache [MAX_FRAMESIZE] |
| int | denoise_filter_cache_size |
| samples in #denoise_filter_cache | |
WMA Voice decoding context.
| int WMAVoiceContext::aw_pulse_range |
the range over which aw_pulse_set1() can apply the pulse, relative to the value in aw_first_pulse_off.
The exact position of the first AW-pulse is within [pulse_off, pulse_off + this], and depends on bitstream values; [16 or 24]
| GetBitContext WMAVoiceContext::gb |
packet bitreader.
During decoder init, it contains the extradata from the demuxer. During decoding, it contains packet data.
| float WMAVoiceContext::zero_exc_pf[MAX_SIGNAL_HISTORY+MAX_SFRAMESIZE] |
zero filter output (i.e.
excitation) by postfilter
1.8.12