/* * SMPTE 302M decoder * Copyright (c) 2008 Laurent Aimar <fenrir@videolan.org> * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com> * * 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" #define AES3_HEADER_LEN 4 typedef struct S302MDecodeContext { AVFrame frame; } S302MDecodeContext; static int s302m_parse_frame_header(AVCodecContext *avctx, const uint8_t *buf, int buf_size) { uint32_t h; int frame_size, channels, bits; if (buf_size <= AES3_HEADER_LEN) { av_log(avctx, AV_LOG_ERROR, "frame is too short\n"); return AVERROR_INVALIDDATA; } /* * AES3 header : * size: 16 * number channels 2 * channel_id 8 * bits per samples 2 * alignments 4 */ h = AV_RB32(buf); frame_size = (h >> 16) & 0xffff; channels = ((h >> 14) & 0x0003) * 2 + 2; bits = ((h >> 4) & 0x0003) * 4 + 16; if (AES3_HEADER_LEN + frame_size != buf_size || bits > 24) { av_log(avctx, AV_LOG_ERROR, "frame has invalid header\n"); return AVERROR_INVALIDDATA; } /* Set output properties */ avctx->bits_per_coded_sample = bits; if (bits > 16) avctx->sample_fmt = AV_SAMPLE_FMT_S32; else avctx->sample_fmt = AV_SAMPLE_FMT_S16; avctx->channels = channels; switch(channels) { case 2: avctx->channel_layout = AV_CH_LAYOUT_STEREO; break; case 4: avctx->channel_layout = AV_CH_LAYOUT_QUAD; break; case 8: avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK | AV_CH_LAYOUT_STEREO_DOWNMIX; } avctx->sample_rate = 48000; avctx->bit_rate = 48000 * avctx->channels * (avctx->bits_per_coded_sample + 4) + 32 * (48000 / (buf_size * 8 / (avctx->channels * (avctx->bits_per_coded_sample + 4)))); return frame_size; } static int s302m_decode_frame(AVCodecContext *avctx, void *data, int *got_frame_ptr, AVPacket *avpkt) { S302MDecodeContext *s = avctx->priv_data; const uint8_t *buf = avpkt->data; int buf_size = avpkt->size; int block_size, ret; int frame_size = s302m_parse_frame_header(avctx, buf, buf_size); if (frame_size < 0) return frame_size; buf_size -= AES3_HEADER_LEN; buf += AES3_HEADER_LEN; /* get output buffer */ block_size = (avctx->bits_per_coded_sample + 4) / 4; s->frame.nb_samples = 2 * (buf_size / block_size) / avctx->channels; if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) { av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n"); return ret; } buf_size = (s->frame.nb_samples * avctx->channels / 2) * block_size; if (avctx->bits_per_coded_sample == 24) { uint32_t *o = (uint32_t *)s->frame.data[0]; for (; buf_size > 6; buf_size -= 7) { *o++ = (av_reverse[buf[2]] << 24) | (av_reverse[buf[1]] << 16) | (av_reverse[buf[0]] << 8); *o++ = (av_reverse[buf[6] & 0xf0] << 28) | (av_reverse[buf[5]] << 20) | (av_reverse[buf[4]] << 12) | (av_reverse[buf[3] & 0x0f] << 4); buf += 7; } } else if (avctx->bits_per_coded_sample == 20) { uint32_t *o = (uint32_t *)s->frame.data[0]; for (; buf_size > 5; buf_size -= 6) { *o++ = (av_reverse[buf[2] & 0xf0] << 28) | (av_reverse[buf[1]] << 20) | (av_reverse[buf[0]] << 12); *o++ = (av_reverse[buf[5] & 0xf0] << 28) | (av_reverse[buf[4]] << 20) | (av_reverse[buf[3]] << 12); buf += 6; } } else { uint16_t *o = (uint16_t *)s->frame.data[0]; for (; buf_size > 4; buf_size -= 5) { *o++ = (av_reverse[buf[1]] << 8) | av_reverse[buf[0]]; *o++ = (av_reverse[buf[4] & 0xf0] << 12) | (av_reverse[buf[3]] << 4) | (av_reverse[buf[2]] >> 4); buf += 5; } } *got_frame_ptr = 1; *(AVFrame *)data = s->frame; return avpkt->size; } static int s302m_decode_init(AVCodecContext *avctx) { S302MDecodeContext *s = avctx->priv_data; avcodec_get_frame_defaults(&s->frame); avctx->coded_frame = &s->frame; return 0; } AVCodec ff_s302m_decoder = { .name = "s302m", .type = AVMEDIA_TYPE_AUDIO, .id = CODEC_ID_S302M, .priv_data_size = sizeof(S302MDecodeContext), .init = s302m_decode_init, .decode = s302m_decode_frame, .capabilities = CODEC_CAP_DR1, .long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"), };