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/* |
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* Copyright (c) CMU 1993 Computer Science, Speech Group |
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* Chengxiang Lu and Alex Hauptmann |
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* Copyright (c) 2005 Steve Underwood <steveu at coppice.org> |
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* Copyright (c) 2009 Kenan Gillet |
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* Copyright (c) 2010 Martin Storsjo |
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* |
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* This file is part of FFmpeg. |
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* |
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* FFmpeg is free software; you can redistribute it and/or |
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* modify it under the terms of the GNU Lesser General Public |
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* License as published by the Free Software Foundation; either |
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* version 2.1 of the License, or (at your option) any later version. |
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* |
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* FFmpeg is distributed in the hope that it will be useful, |
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* but WITHOUT ANY WARRANTY; without even the implied warranty of |
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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* Lesser General Public License for more details. |
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* |
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* You should have received a copy of the GNU Lesser General Public |
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* License along with FFmpeg; if not, write to the Free Software |
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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*/ |
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/** |
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* @file |
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* G.722 ADPCM audio decoder |
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* |
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* This G.722 decoder is a bit-exact implementation of the ITU G.722 |
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* specification for all three specified bitrates - 64000bps, 56000bps |
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* and 48000bps. It passes the ITU tests. |
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* |
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* @note For the 56000bps and 48000bps bitrates, the lowest 1 or 2 bits |
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* respectively of each byte are ignored. |
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*/ |
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#include "libavutil/channel_layout.h" |
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#include "libavutil/opt.h" |
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#include "avcodec.h" |
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#include "get_bits.h" |
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#include "g722.h" |
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#include "internal.h" |
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#define OFFSET(x) offsetof(G722Context, x) |
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#define AD AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_DECODING_PARAM |
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static const AVOption options[] = { |
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{ "bits_per_codeword", "Bits per G722 codeword", OFFSET(bits_per_codeword), AV_OPT_TYPE_INT, { .i64 = 8 }, 6, 8, AD }, |
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{ NULL } |
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}; |
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static const AVClass g722_decoder_class = { |
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.class_name = "g722 decoder", |
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.item_name = av_default_item_name, |
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.option = options, |
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.version = LIBAVUTIL_VERSION_INT, |
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}; |
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static av_cold int g722_decode_init(AVCodecContext * avctx) |
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{ |
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G722Context *c = avctx->priv_data; |
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avctx->channels = 1; |
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avctx->channel_layout = AV_CH_LAYOUT_MONO; |
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avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
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c->band[0].scale_factor = 8; |
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c->band[1].scale_factor = 2; |
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c->prev_samples_pos = 22; |
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ff_g722dsp_init(&c->dsp); |
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return 0; |
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} |
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static const int16_t low_inv_quant5[32] = { |
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-35, -35, -2919, -2195, -1765, -1458, -1219, -1023, |
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-858, -714, -587, -473, -370, -276, -190, -110, |
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2919, 2195, 1765, 1458, 1219, 1023, 858, 714, |
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587, 473, 370, 276, 190, 110, 35, -35 |
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}; |
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static const int16_t * const low_inv_quants[3] = { ff_g722_low_inv_quant6, |
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low_inv_quant5, |
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ff_g722_low_inv_quant4 }; |
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static int g722_decode_frame(AVCodecContext *avctx, void *data, |
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int *got_frame_ptr, AVPacket *avpkt) |
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{ |
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G722Context *c = avctx->priv_data; |
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AVFrame *frame = data; |
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int16_t *out_buf; |
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int j, ret; |
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const int skip = 8 - c->bits_per_codeword; |
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const int16_t *quantizer_table = low_inv_quants[skip]; |
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GetBitContext gb; |
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/* get output buffer */ |
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frame->nb_samples = avpkt->size * 2; |
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✗✓ |
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if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
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return ret; |
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out_buf = (int16_t *)frame->data[0]; |
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ret = init_get_bits8(&gb, avpkt->data, avpkt->size); |
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✗✓ |
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if (ret < 0) |
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return ret; |
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✓✓ |
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for (j = 0; j < avpkt->size; j++) { |
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int ilow, ihigh, rlow, rhigh, dhigh; |
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int xout[2]; |
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ihigh = get_bits(&gb, 2); |
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ilow = get_bits(&gb, 6 - skip); |
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skip_bits(&gb, skip); |
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rlow = av_clip_intp2((c->band[0].scale_factor * quantizer_table[ilow] >> 10) |
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+ c->band[0].s_predictor, 14); |
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ff_g722_update_low_predictor(&c->band[0], ilow >> (2 - skip)); |
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dhigh = c->band[1].scale_factor * ff_g722_high_inv_quant[ihigh] >> 10; |
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rhigh = av_clip_intp2(dhigh + c->band[1].s_predictor, 14); |
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ff_g722_update_high_predictor(&c->band[1], dhigh, ihigh); |
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c->prev_samples[c->prev_samples_pos++] = rlow + rhigh; |
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c->prev_samples[c->prev_samples_pos++] = rlow - rhigh; |
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c->dsp.apply_qmf(c->prev_samples + c->prev_samples_pos - 24, xout); |
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*out_buf++ = av_clip_int16(xout[0] >> 11); |
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*out_buf++ = av_clip_int16(xout[1] >> 11); |
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✓✓ |
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if (c->prev_samples_pos >= PREV_SAMPLES_BUF_SIZE) { |
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memmove(c->prev_samples, c->prev_samples + c->prev_samples_pos - 22, |
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22 * sizeof(c->prev_samples[0])); |
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c->prev_samples_pos = 22; |
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} |
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} |
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*got_frame_ptr = 1; |
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return avpkt->size; |
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} |
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AVCodec ff_adpcm_g722_decoder = { |
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.name = "g722", |
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.long_name = NULL_IF_CONFIG_SMALL("G.722 ADPCM"), |
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.type = AVMEDIA_TYPE_AUDIO, |
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.id = AV_CODEC_ID_ADPCM_G722, |
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.priv_data_size = sizeof(G722Context), |
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.init = g722_decode_init, |
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.decode = g722_decode_frame, |
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.capabilities = AV_CODEC_CAP_DR1 | AV_CODEC_CAP_CHANNEL_CONF, |
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.priv_class = &g722_decoder_class, |
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}; |