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Diffstat (limited to 'ffmpeg/libavcodec/g722dec.c')
| -rw-r--r-- | ffmpeg/libavcodec/g722dec.c | 149 |
1 files changed, 149 insertions, 0 deletions
diff --git a/ffmpeg/libavcodec/g722dec.c b/ffmpeg/libavcodec/g722dec.c new file mode 100644 index 0000000..1a489a7 --- /dev/null +++ b/ffmpeg/libavcodec/g722dec.c @@ -0,0 +1,149 @@ +/* + * 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 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 + */ + +/** + * @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) + 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, +}; |