/* * Copyright (c) CMU 1993 Computer Science, Speech Group * Chengxiang Lu and Alex Hauptmann * Copyright (c) 2005 Steve Underwood <steveu at coppice.org> * Copyright (c) 2009 Kenan Gillet * Copyright (c) 2010 Martin Storsjo * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * G.722 ADPCM audio decoder * * This G.722 decoder is a bit-exact implementation of the ITU G.722 * specification for all three specified bitrates - 64000bps, 56000bps * and 48000bps. It passes the ITU tests. * * @note For the 56000bps and 48000bps bitrates, the lowest 1 or 2 bits * respectively of each byte are ignored. */ #include "libavutil/channel_layout.h" #include "libavutil/opt.h" #include "avcodec.h" #include "get_bits.h" #include "g722.h" #include "internal.h" #define OFFSET(x) offsetof(G722Context, x) #define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM static const AVOption options[] = { { "bits_per_codeword", "Bits per G722 codeword", OFFSET(bits_per_codeword), AV_OPT_TYPE_FLAGS, { .i64 = 8 }, 6, 8, AD }, { NULL } }; static const AVClass g722_decoder_class = { .class_name = "g722 decoder", .item_name = av_default_item_name, .option = options, .version = LIBAVUTIL_VERSION_INT, }; static av_cold int g722_decode_init(AVCodecContext * avctx) { G722Context *c = avctx->priv_data; avctx->channels = 1; avctx->channel_layout = AV_CH_LAYOUT_MONO; avctx->sample_fmt = AV_SAMPLE_FMT_S16; c->band[0].scale_factor = 8; c->band[1].scale_factor = 2; c->prev_samples_pos = 22; return 0; } static const int16_t low_inv_quant5[32] = { -35, -35, -2919, -2195, -1765, -1458, -1219, -1023, -858, -714, -587, -473, -370, -276, -190, -110, 2919, 2195, 1765, 1458, 1219, 1023, 858, 714, 587, 473, 370, 276, 190, 110, 35, -35 }; static const int16_t *low_inv_quants[3] = { ff_g722_low_inv_quant6, low_inv_quant5, ff_g722_low_inv_quant4 }; static int g722_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt) { G722Context *c = avctx->priv_data; AVFrame *frame = data; int16_t *out_buf; int j, ret; const int skip = 8 - c->bits_per_codeword; const int16_t *quantizer_table = low_inv_quants[skip]; GetBitContext gb; /* get output buffer */ frame->nb_samples = avpkt->size * 2; if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return ret; } out_buf = (int16_t *)frame->data[0]; init_get_bits(&gb, avpkt->data, avpkt->size * 8); for (j = 0; j < avpkt->size; j++) { int ilow, ihigh, rlow, rhigh, dhigh; int xout1, xout2; ihigh = get_bits(&gb, 2); ilow = get_bits(&gb, 6 - skip); skip_bits(&gb, skip); rlow = av_clip((c->band[0].scale_factor * quantizer_table[ilow] >> 10) + c->band[0].s_predictor, -16384, 16383); ff_g722_update_low_predictor(&c->band[0], ilow >> (2 - skip)); dhigh = c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10; rhigh = av_clip(dhigh + c->band[1].s_predictor, -16384, 16383); ff_g722_update_high_predictor(&c->band[1], dhigh, ihigh); c->prev_samples[c->prev_samples_pos++] = rlow + rhigh; c->prev_samples[c->prev_samples_pos++] = rlow - rhigh; ff_g722_apply_qmf(c->prev_samples + c->prev_samples_pos - 24, &xout1, &xout2); *out_buf++ = av_clip_int16(xout1 >> 11); *out_buf++ = av_clip_int16(xout2 >> 11); if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) { memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22, 22 * sizeof(c->prev_samples[0])); c->prev_samples_pos = 22; } } *got_frame_ptr = 1; return avpkt->size; } AVCodec ff_adpcm_g722_decoder = { .name = "g722", .type = AVMEDIA_TYPE_AUDIO, .id = AV_CODEC_ID_ADPCM_G722, .priv_data_size = sizeof(G722Context), .init = g722_decode_init, .decode = g722_decode_frame, .capabilities = CODEC_CAP_DR1, .long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"), .priv_class = &g722_decoder_class, };