diff options
Diffstat (limited to 'libavcodec/dvaudiodec.c')
-rw-r--r-- | libavcodec/dvaudiodec.c | 133 |
1 files changed, 133 insertions, 0 deletions
diff --git a/libavcodec/dvaudiodec.c b/libavcodec/dvaudiodec.c new file mode 100644 index 0000000..5aa2a95 --- /dev/null +++ b/libavcodec/dvaudiodec.c @@ -0,0 +1,133 @@ +/* + * Copyright (c) 2012 Laurent Aimar + * + * 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 "libavutil/intreadwrite.h" +#include "avcodec.h" +#include "internal.h" +#include "dvaudio.h" + +typedef struct DVAudioContext { + int block_size; + int is_12bit; + int is_pal; + int16_t shuffle[2000]; +} DVAudioContext; + +static av_cold int decode_init(AVCodecContext *avctx) +{ + DVAudioContext *s = avctx->priv_data; + int i; + + if (avctx->channels != 2) { + av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n"); + return AVERROR(EINVAL); + } + + if (avctx->codec_tag == 0x0215) { + s->block_size = 7200; + } else if (avctx->codec_tag == 0x0216) { + s->block_size = 8640; + } else if (avctx->block_align == 7200 || + avctx->block_align == 8640) { + s->block_size = avctx->block_align; + } else { + return AVERROR(EINVAL); + } + + s->is_pal = s->block_size == 8640; + s->is_12bit = avctx->bits_per_coded_sample == 12; + avctx->sample_fmt = AV_SAMPLE_FMT_S16; + avctx->channel_layout = AV_CH_LAYOUT_STEREO; + + for (i = 0; i < FF_ARRAY_ELEMS(s->shuffle); i++) { + const unsigned a = s->is_pal ? 18 : 15; + const unsigned b = 3 * a; + + s->shuffle[i] = 80 * ((21 * (i % 3) + 9 * (i / 3) + ((i / a) % 3)) % b) + + (2 + s->is_12bit) * (i / b) + 8; + } + + return 0; +} + +static inline uint16_t dv_audio_12to16(uint16_t sample) +{ + uint16_t shift, result; + + sample = (sample < 0x800) ? sample : sample | 0xf000; + shift = (sample & 0xf00) >> 8; + + if (shift < 0x2 || shift > 0xd) { + result = sample; + } else if (shift < 0x8) { + shift--; + result = (sample - (256 * shift)) << shift; + } else { + shift = 0xe - shift; + result = ((sample + ((256 * shift) + 1)) << shift) - 1; + } + + return result; +} + +static int decode_frame(AVCodecContext *avctx, void *data, + int *got_frame_ptr, AVPacket *pkt) +{ + DVAudioContext *s = avctx->priv_data; + AVFrame *frame = data; + const uint8_t *src = pkt->data; + int16_t *dst; + int ret, i; + + if (pkt->size < s->block_size) + return AVERROR_INVALIDDATA; + + frame->nb_samples = dv_get_audio_sample_count(pkt->data + 244, s->is_pal); + if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) + return ret; + dst = (int16_t *)frame->data[0]; + + for (i = 0; i < frame->nb_samples; i++) { + const uint8_t *v = &src[s->shuffle[i]]; + + if (s->is_12bit) { + *dst++ = dv_audio_12to16((v[0] << 4) | ((v[2] >> 4) & 0x0f)); + *dst++ = dv_audio_12to16((v[1] << 4) | ((v[2] >> 0) & 0x0f)); + } else { + *dst++ = AV_RB16(&v[0]); + *dst++ = AV_RB16(&v[s->is_pal ? 4320 : 3600]); + } + } + + *got_frame_ptr = 1; + + return s->block_size; +} + +AVCodec ff_dvaudio_decoder = { + .name = "dvaudio", + .long_name = NULL_IF_CONFIG_SMALL("Ulead DV Audio"), + .type = AVMEDIA_TYPE_AUDIO, + .id = AV_CODEC_ID_DVAUDIO, + .init = decode_init, + .decode = decode_frame, + .capabilities = AV_CODEC_CAP_DR1, + .priv_data_size = sizeof(DVAudioContext), +}; |