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ffmpeg/libavcodec/wma.h
bnnm 19802d170a avcodec/wmadec: fix WMA gapless playback 
Fixes trac issue #7473.

Removes encoder delay (skip samples) and writes remaining frame samples after EOF to get correct sample count.

Output is now accurate vs players that use Microsoft's codecs (Windows Media Format Runtime).

Tested vs encode>decode WMAv2 with MS's codecs and most sample rate/bit rate/channel/mode combinations in ASF/XWMA.
WMAv1 appears to use the same delay, from FFmpeg samples.

Signed-off-by: bnnm <bananaman255@gmail.com>
2021-09-12 22:23:35 +02:00

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/*
* WMA compatible codec
* Copyright (c) 2002-2007 The FFmpeg Project
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef AVCODEC_WMA_H
#define AVCODEC_WMA_H
#include "libavutil/float_dsp.h"
#include "libavutil/mem_internal.h"
#include "avcodec.h"
#include "fft.h"
#include "get_bits.h"
#include "put_bits.h"
/* size of blocks */
#define BLOCK_MIN_BITS 7
#define BLOCK_MAX_BITS 11
#define BLOCK_MAX_SIZE (1 << BLOCK_MAX_BITS)
#define BLOCK_NB_SIZES (BLOCK_MAX_BITS - BLOCK_MIN_BITS + 1)
/* XXX: find exact max size */
#define HIGH_BAND_MAX_SIZE 16
#define NB_LSP_COEFS 10
/* XXX: is it a suitable value ? */
#define MAX_CODED_SUPERFRAME_SIZE 32768
#define MAX_CHANNELS 2
#define NOISE_TAB_SIZE 8192
#define LSP_POW_BITS 7
// FIXME should be in wmadec
#define VLCBITS 9
#define VLCMAX ((22 + VLCBITS - 1) / VLCBITS)
typedef float WMACoef; ///< type for decoded coefficients, int16_t would be enough for wma 1/2
typedef struct CoefVLCTable {
int n; ///< total number of codes
int max_level;
const uint32_t *huffcodes; ///< VLC bit values
const uint8_t *huffbits; ///< VLC bit size
const uint16_t *levels; ///< table to build run/level tables
} CoefVLCTable;
typedef struct WMACodecContext {
AVCodecContext *avctx;
GetBitContext gb;
PutBitContext pb;
int version; ///< 1 = 0x160 (WMAV1), 2 = 0x161 (WMAV2)
int use_bit_reservoir;
int use_variable_block_len;
int use_exp_vlc; ///< exponent coding: 0 = lsp, 1 = vlc + delta
int use_noise_coding; ///< true if perceptual noise is added
int byte_offset_bits;
VLC exp_vlc;
int exponent_sizes[BLOCK_NB_SIZES];
uint16_t exponent_bands[BLOCK_NB_SIZES][25];
int high_band_start[BLOCK_NB_SIZES]; ///< index of first coef in high band
int coefs_start; ///< first coded coef
int coefs_end[BLOCK_NB_SIZES]; ///< max number of coded coefficients
int exponent_high_sizes[BLOCK_NB_SIZES];
int exponent_high_bands[BLOCK_NB_SIZES][HIGH_BAND_MAX_SIZE];
VLC hgain_vlc;
/* coded values in high bands */
int high_band_coded[MAX_CHANNELS][HIGH_BAND_MAX_SIZE];
int high_band_values[MAX_CHANNELS][HIGH_BAND_MAX_SIZE];
/* there are two possible tables for spectral coefficients */
// FIXME the following 3 tables should be shared between decoders
VLC coef_vlc[2];
uint16_t *run_table[2];
float *level_table[2];
uint16_t *int_table[2];
const CoefVLCTable *coef_vlcs[2];
/* frame info */
int frame_len; ///< frame length in samples
int frame_len_bits; ///< frame_len = 1 << frame_len_bits
int nb_block_sizes; ///< number of block sizes
/* block info */
int reset_block_lengths;
int block_len_bits; ///< log2 of current block length
int next_block_len_bits; ///< log2 of next block length
int prev_block_len_bits; ///< log2 of prev block length
int block_len; ///< block length in samples
int block_num; ///< block number in current frame
int block_pos; ///< current position in frame
uint8_t ms_stereo; ///< true if mid/side stereo mode
uint8_t channel_coded[MAX_CHANNELS]; ///< true if channel is coded
int exponents_bsize[MAX_CHANNELS]; ///< log2 ratio frame/exp. length
DECLARE_ALIGNED(32, float, exponents)[MAX_CHANNELS][BLOCK_MAX_SIZE];
float max_exponent[MAX_CHANNELS];
WMACoef coefs1[MAX_CHANNELS][BLOCK_MAX_SIZE];
DECLARE_ALIGNED(32, float, coefs)[MAX_CHANNELS][BLOCK_MAX_SIZE];
DECLARE_ALIGNED(32, FFTSample, output)[BLOCK_MAX_SIZE * 2];
FFTContext mdct_ctx[BLOCK_NB_SIZES];
const float *windows[BLOCK_NB_SIZES];
/* output buffer for one frame and the last for IMDCT windowing */
DECLARE_ALIGNED(32, float, frame_out)[MAX_CHANNELS][BLOCK_MAX_SIZE * 2];
/* last frame info */
uint8_t last_superframe[MAX_CODED_SUPERFRAME_SIZE + AV_INPUT_BUFFER_PADDING_SIZE]; /* padding added */
int last_bitoffset;
int last_superframe_len;
int exponents_initialized[MAX_CHANNELS];
float noise_table[NOISE_TAB_SIZE];
int noise_index;
float noise_mult; /* XXX: suppress that and integrate it in the noise array */
/* lsp_to_curve tables */
float lsp_cos_table[BLOCK_MAX_SIZE];
float lsp_pow_e_table[256];
float lsp_pow_m_table1[(1 << LSP_POW_BITS)];
float lsp_pow_m_table2[(1 << LSP_POW_BITS)];
AVFloatDSPContext *fdsp;
int eof_done; /* decode flag to output remaining samples after EOF */
#ifdef TRACE
int frame_count;
#endif /* TRACE */
} WMACodecContext;
extern const uint8_t ff_wma_hgain_hufftab[37][2];
extern const float ff_wma_lsp_codebook[NB_LSP_COEFS][16];
extern const uint32_t ff_aac_scalefactor_code[121];
extern const uint8_t ff_aac_scalefactor_bits[121];
av_warn_unused_result
int ff_wma_init(AVCodecContext *avctx, int flags2);
int ff_wma_total_gain_to_bits(int total_gain);
int ff_wma_end(AVCodecContext *avctx);
unsigned int ff_wma_get_large_val(GetBitContext *gb);
int ff_wma_run_level_decode(AVCodecContext *avctx, GetBitContext *gb,
VLC *vlc, const float *level_table,
const uint16_t *run_table, int version,
WMACoef *ptr, int offset, int num_coefs,
int block_len, int frame_len_bits,
int coef_nb_bits);
#endif /* AVCODEC_WMA_H */
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