[FFmpeg-devel] [PATCH 4/8] avcodec/g728dec: G.728 decoder
Andreas Rheinhardt
andreas.rheinhardt at outlook.com
Sun Jan 12 15:48:00 EET 2025
Peter Ross:
> ---
> libavcodec/Makefile | 1 +
> libavcodec/allcodecs.c | 1 +
> libavcodec/codec_desc.c | 7 ++
> libavcodec/codec_id.h | 1 +
> libavcodec/g728data.h | 70 +++++++++++++
> libavcodec/g728dec.c | 213 ++++++++++++++++++++++++++++++++++++++++
> libavcodec/utils.c | 1 +
> 7 files changed, 294 insertions(+)
> create mode 100644 libavcodec/g728data.h
> create mode 100644 libavcodec/g728dec.c
>
> diff --git a/libavcodec/Makefile b/libavcodec/Makefile
> index a3ef11a258..6400d73115 100644
> --- a/libavcodec/Makefile
> +++ b/libavcodec/Makefile
> @@ -394,6 +394,7 @@ OBJS-$(CONFIG_G723_1_DECODER) += g723_1dec.o g723_1.o \
> acelp_vectors.o celp_filters.o celp_math.o
> OBJS-$(CONFIG_G723_1_ENCODER) += g723_1enc.o g723_1.o \
> acelp_vectors.o celp_filters.o celp_math.o
> +OBJS-$(CONFIG_G728_DECODER) += g728dec.o
> OBJS-$(CONFIG_G729_DECODER) += g729dec.o lsp.o celp_math.o celp_filters.o acelp_filters.o acelp_pitch_delay.o acelp_vectors.o g729postfilter.o
> OBJS-$(CONFIG_GDV_DECODER) += gdv.o
> OBJS-$(CONFIG_GEM_DECODER) += gemdec.o
> diff --git a/libavcodec/allcodecs.c b/libavcodec/allcodecs.c
> index af2a2b36e4..0975de5103 100644
> --- a/libavcodec/allcodecs.c
> +++ b/libavcodec/allcodecs.c
> @@ -475,6 +475,7 @@ extern const FFCodec ff_flac_decoder;
> extern const FFCodec ff_ftr_decoder;
> extern const FFCodec ff_g723_1_encoder;
> extern const FFCodec ff_g723_1_decoder;
> +extern const FFCodec ff_g728_decoder;
> extern const FFCodec ff_g729_decoder;
> extern const FFCodec ff_gsm_decoder;
> extern const FFCodec ff_gsm_ms_decoder;
> diff --git a/libavcodec/codec_desc.c b/libavcodec/codec_desc.c
> index b734d07ded..d8bd30d0e1 100644
> --- a/libavcodec/codec_desc.c
> +++ b/libavcodec/codec_desc.c
> @@ -3466,6 +3466,13 @@ static const AVCodecDescriptor codec_descriptors[] = {
> .long_name = NULL_IF_CONFIG_SMALL("LC3 (Low Complexity Communication Codec)"),
> .props = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
> },
> + {
> + .id = AV_CODEC_ID_G728,
> + .type = AVMEDIA_TYPE_AUDIO,
> + .name = "g728",
> + .long_name = NULL_IF_CONFIG_SMALL("G.728"),
> + .props = AV_CODEC_PROP_INTRA_ONLY | AV_CODEC_PROP_LOSSY,
> + },
>
> /* subtitle codecs */
> {
> diff --git a/libavcodec/codec_id.h b/libavcodec/codec_id.h
> index 97b70c5bf5..ee02fe4261 100644
> --- a/libavcodec/codec_id.h
> +++ b/libavcodec/codec_id.h
> @@ -552,6 +552,7 @@ enum AVCodecID {
> AV_CODEC_ID_OSQ,
> AV_CODEC_ID_QOA,
> AV_CODEC_ID_LC3,
> + AV_CODEC_ID_G728,
>
> /* subtitle codecs */
> AV_CODEC_ID_FIRST_SUBTITLE = 0x17000, ///< A dummy ID pointing at the start of subtitle codecs.
> diff --git a/libavcodec/g728data.h b/libavcodec/g728data.h
> new file mode 100644
> index 0000000000..a2ddf5682d
> --- /dev/null
> +++ b/libavcodec/g728data.h
> @@ -0,0 +1,70 @@
> +/*
> + * G.728 decoder
> + *
> + * 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_G728DATA_H
> +#define AVCODEC_G728DATA_H
> +
> +#include <stdint.h>
> +#include "libavutil/macros.h"
> +
> +#define IDIM 5 /* Vector dimension (excitation block size) */
> +#define LPC 50 /* Synthesis filter order */
> +#define LPCLG 10 /* Log-gain predictor order */
> +#define NFRSZ 20 /* Frame size (adaptation cycle size in samples */
> +#define NONR 35 /* Number of non-recursive window samples for synthesis filter */
> +#define NONRLG 20 /* Number of non-recursive window samples for log-gain predictor */
> +#define NUPDATE 4 /* Predictor update period (in terms of vectors) */
> +
> +#define NSBSZ (LPC + NONR + NFRSZ)
> +#define NSBGSZ (LPCLG + NONRLG + NUPDATE)
> +
> +// Hybrid window for the synthesis filter
> +static const uint16_t g728_wnr[NSBSZ] = {
> + 1565, 3127, 4681, 6225, 7755, 9266, 10757, 12223, 13661, 15068,
> + 16441, 17776, 19071, 20322, 21526, 22682, 23786, 24835, 25828, 26761,
> + 27634, 28444, 29188, 29866, 30476, 31016, 31486, 31884, 32208, 32460,
> + 32637, 32739, 32767, 32721, 32599, 32403, 32171, 31940, 31711, 31484,
> + 31259, 31034, 30812, 30591, 30372, 30154, 29938, 29724, 29511, 29299,
> + 29089, 28881, 28674, 28468, 28264, 28062, 27861, 27661, 27463, 27266,
> + 27071, 26877, 26684, 26493, 26303, 26114, 25927, 25742, 25557, 25374,
> + 25192, 25012, 24832, 24654, 24478, 24302, 24128, 23955, 23784, 23613,
> + 23444, 23276, 23109, 22943, 22779, 22616, 22454, 22293, 22133, 21974,
> + 21817, 21661, 21505, 21351, 21198, 21046, 20896, 20746, 20597, 20450,
> + 20303, 20157, 20013, 19870, 19727
> +};
> +
> +// Hybrid window for the log-gain predictor
> +static const uint16_t g728_wnrg[NSBGSZ] = {
> + 3026, 6025, 8973, 11845, 14615, 17261, 19759, 22088, 24228, 26162,
> + 27872, 29344, 30565, 31525, 32216, 32631, 32767, 32625, 32203, 31506,
> + 30540, 29461, 28420, 27416, 26448, 25514, 24613, 23743, 22905, 22096,
> + 21315, 20562, 19836, 19135
> +};
> +
> +// Values for bandwidth broadcasting
> +static const uint16_t g728_facv[LPC] = {
> + 16192, 16002, 15815, 15629, 15446, 15265, 15086, 14910, 14735, 14562,
> + 14391, 14223, 14056, 13891, 13729, 13568, 13409, 13252, 13096, 12943,
> + 12791, 12641, 12493, 12347, 12202, 12059, 11918, 11778, 11640, 11504,
> + 11369, 11236, 11104, 10974, 10845, 10718, 10593, 10468, 10346, 10225,
> + 10105, 9986, 9869, 9754, 9639, 9526, 9415, 9304, 9195, 9088
> +};
> +
> +#endif /* AVCODEC_G728DATA_H */
> diff --git a/libavcodec/g728dec.c b/libavcodec/g728dec.c
> new file mode 100644
> index 0000000000..ff861ff1c0
> --- /dev/null
> +++ b/libavcodec/g728dec.c
> @@ -0,0 +1,213 @@
> +/*
> + * G.728 decoder
> + * Copyright (c) 2025 Peter Ross
> + *
> + * 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
> + */
> +
> +#include "avcodec.h"
> +#include "celp_filters.h"
> +#include "codec_internal.h"
> +#include "decode.h"
> +#include "get_bits.h"
> +#include "g728data.h"
> +#include "lpc_functions.h"
> +#include "ra288.h"
> +#include "libavutil/float_dsp.h"
> +#include "libavutil/mem.h"
> +#include "libavutil/mem_internal.h"
> +#include "libavutil/opt.h"
> +#include "libavutil/thread.h"
> +
> +#define MAX_BACKWARD_FILTER_ORDER LPC
> +#define MAX_BACKWARD_FILTER_LEN NFRSZ
> +#define MAX_BACKWARD_FILTER_NONREC NONR
> +#define ATTEN 0.75f
> +#include "g728_template.c"
> +
> +#define LPCW 10 /* Perceptual weighting filter order */
> +#define GOFF 32.0f /* Log-gain offset value */
> +
> +static float g728_gq_db[8];
> +static float g728_y_db[128];
> +static float g728_wnr_r[FFALIGN(NSBSZ,16)];
> +static float g728_wnrg_r[FFALIGN(NSBGSZ, 16)];
> +static float g728_facv_f[FFALIGN(LPC, 16)];
> +
> +static av_cold void g728_init_static_data(void)
> +{
> + for(int i = 0; i < FF_ARRAY_ELEMS(amptable); i++)
> + g728_gq_db[i] = 10.0f*log10f(amptable[i] * amptable[i]);
> +
> + for (int i = 0; i < FF_ARRAY_ELEMS(codetable); i++) {
> + float cby[IDIM];
> + for (int j = 0; j < IDIM; j++)
> + cby[j] = codetable[i][j] * (1.0f/(1<<11));
> + g728_y_db[i] = 10.0f*log10f(avpriv_scalarproduct_float_c(cby, cby, IDIM) / IDIM);
> + }
> +
> + for (int i = 0; i < NSBSZ; i++)
> + g728_wnr_r[i] = g728_wnr[NSBSZ - 1 - i] * (1.0f/(1<<15));
> + for (int i = 0; i < NSBGSZ; i++)
> + g728_wnrg_r[i] = g728_wnrg[NSBGSZ - 1 - i] * (1.0f/(1<<15));
> + for (int i = 0; i < LPC; i++)
> + g728_facv_f[i] = g728_facv[i] * (1.0f/(1<<14));
> +}
> +
> +typedef struct {
> + AVFloatDSPContext *fdsp;
> + int valid;
> + float a[LPC];
> + DECLARE_ALIGNED(32, float, sb)[NSBSZ];
> + DECLARE_ALIGNED(32, float, sbg)[NSBGSZ];
> + DECLARE_ALIGNED(32, float, gp)[FFALIGN(LPCLG, 16)];
> + DECLARE_ALIGNED(32, float, atmp)[FFALIGN(LPC, 16)];
> + float rexp[LPC + 1];
> + float rexpg[LPCLG + 1];
> + float r[LPC + 1];
> + float alpha;
> +} G728Context;
> +
> +static av_cold int g728_decode_init(AVCodecContext *avctx)
> +{
> + static AVOnce init_static_once = AV_ONCE_INIT;
> + G728Context *s = avctx->priv_data;
> +
> + s->fdsp = avpriv_float_dsp_alloc(avctx->flags & AV_CODEC_FLAG_BITEXACT);
> + if (!s->fdsp)
> + return AVERROR(ENOMEM);
> +
> + s->gp[0] = -1.0f;
> + for (int i = 0; i < NUPDATE; i++)
> + s->sbg[NSBGSZ - 1 -i] = -GOFF;
> +
> + avctx->sample_fmt = AV_SAMPLE_FMT_FLT;
> +
> + ff_thread_once(&init_static_once, g728_init_static_data);
> + return 0;
> +}
> +
> +static av_cold int g728_decode_close(AVCodecContext *avctx)
> +{
> + G728Context *s = avctx->priv_data;
> + av_freep(&s->fdsp);
> + return 0;
> +}
> +
> +static int hybrid_window(AVFloatDSPContext *fdsp,
> + int order, int n, int non_rec, float *out,
> + const float *hist, float *out2, const float *window)
> +{
> + do_hybrid_window(fdsp->vector_fmul, order, n, non_rec, out, hist, out2, window);
> + return out[order] != 0.0f;
> +}
> +
> +static void decode_frame(G728Context *s, GetBitContext *gb, float *dst)
> +{
> + float *gstate = s->sbg + NSBGSZ - 2;
> +
> + for (int idx = 0; idx < NUPDATE; idx++) {
> + DECLARE_ALIGNED(32, float, et)[IDIM];
> + float *statelpc = s->sb + NSBSZ - NFRSZ + idx*IDIM;
> + float gain, gain_db;
> + int is, ig;
> +
> + gain_db = 0.0f;
> + for (int i = 0; i < LPCLG; i++)
> + gain_db -= s->gp[i] * gstate[-i];
> + gain_db = av_clipf(gain_db, -GOFF, 28.0f);
> +
> + is = get_bits(gb, 7); // shape index
> + ig = get_bits(gb, 3); // gain index
> +
> + gain = powf(10.0f, (gain_db + GOFF) * .05f) * amptable[ig] * (1.0f/(1<<11));
> + for (int i = 0; i < IDIM; i++)
> + et[i] = codetable[is][i] * gain;
> +
> + ff_celp_lp_synthesis_filterf(statelpc, s->a, et, IDIM, LPC);
> +
> + for (int i = 0; i < IDIM; i++) {
> + statelpc[i] = av_clipf(statelpc[i], -4095.0f, 4095.0f);
> + dst[idx*IDIM + i] = statelpc[i] * (1.0f/(1<<12));
> + }
> +
> + gstate++;
> + *gstate = FFMAX(-GOFF, g728_gq_db[ig] + g728_y_db[is] + gain_db);
> +
> + if (idx == 0) {
> + DECLARE_ALIGNED(32, float, gptmp)[FFALIGN(LPCLG, 16)];
> + if (s->valid && (s->valid = !compute_lpc_coefs(s->r + 1, LPCW, LPC, s->atmp, 0, 0, 1, &s->alpha))) {
> + s->fdsp->vector_fmul(s->atmp, s->atmp, g728_facv_f, FFALIGN(LPC, 16));
> + }
> + if (hybrid_window(s->fdsp, LPCLG, NUPDATE, NONRLG, s->r, s->sbg, s->rexpg, g728_wnrg_r) &&
> + !compute_lpc_coefs(s->r, 0, LPCLG, gptmp, 0, 0, 1, &s->alpha)) {
> + s->fdsp->vector_fmul(s->gp, gptmp, gain_bw_tab, FFALIGN(LPCLG, 16));
> + }
> + memmove(s->sbg, s->sbg + NUPDATE, sizeof(float)*(LPCLG + NONRLG));
> + gstate = s->sbg + NSBGSZ - 1 - NUPDATE;
> + } else if (idx == 1) {
> + if (s->valid)
> + memcpy(s->a, s->atmp, sizeof(float)*LPC);
> + }
> + }
> +
> + s->valid = 0;
> + if (hybrid_window(s->fdsp, LPC, NFRSZ, NONR, s->r, s->sb, s->rexp, g728_wnr_r)) {
> + s->valid = !compute_lpc_coefs(s->r, 0, LPCW, s->atmp, 0, 0, 1, &s->alpha);
> + }
> +
> + memmove(s->sb, s->sb + NFRSZ, sizeof(float)*(LPC + NONR));
> +}
> +
> +static int g728_decode_frame(AVCodecContext *avctx, AVFrame *frame,
> + int *got_frame_ptr, AVPacket *avpkt)
> +{
> + G728Context *s = avctx->priv_data;
> + GetBitContext gb;
> + int ret;
> +
> + if (avpkt->size < 5)
> + return AVERROR_INVALIDDATA;
> +
> + if ((ret = init_get_bits8(&gb, avpkt->data, avpkt->size)) < 0)
> + return ret;
> +
> + frame->nb_samples = 20;
> + if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
> + return ret;
> +
> + decode_frame(s, &gb, (float *)frame->data[0]);
> +
> + *got_frame_ptr = 1;
> +
> + return 5;
Won't decoding in 5 byte blocks incur a lot of overhead?
> +}
> +
> +const FFCodec ff_g728_decoder = {
> + .p.name = "g728",
> + CODEC_LONG_NAME("G.728)"),
> + .p.type = AVMEDIA_TYPE_AUDIO,
> + .p.id = AV_CODEC_ID_G728,
> + .priv_data_size = sizeof(G728Context),
> + .init = g728_decode_init,
> + .close = g728_decode_close,
> + FF_CODEC_DECODE_CB(g728_decode_frame),
> + .p.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
> + AV_CODEC_CAP_DR1,
> + .p.sample_fmts = (const enum AVSampleFormat[]) { AV_SAMPLE_FMT_FLT,
> + AV_SAMPLE_FMT_NONE },
> +};
> diff --git a/libavcodec/utils.c b/libavcodec/utils.c
> index dd846b4ae9..58b29c4c9d 100644
> --- a/libavcodec/utils.c
> +++ b/libavcodec/utils.c
> @@ -553,6 +553,7 @@ int av_get_bits_per_sample(enum AVCodecID codec_id)
> case AV_CODEC_ID_DFPWM:
> return 1;
> case AV_CODEC_ID_ADPCM_SBPRO_2:
> + case AV_CODEC_ID_G728:
> return 2;
> case AV_CODEC_ID_ADPCM_SBPRO_3:
> return 3;
>
>
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