| 1 | /* |
| 2 | * SMPTE 302M decoder |
| 3 | * Copyright (c) 2008 Laurent Aimar <fenrir@videolan.org> |
| 4 | * Copyright (c) 2009 Baptiste Coudurier <baptiste.coudurier@gmail.com> |
| 5 | * |
| 6 | * This file is part of FFmpeg. |
| 7 | * |
| 8 | * FFmpeg is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU Lesser General Public |
| 10 | * License as published by the Free Software Foundation; either |
| 11 | * version 2.1 of the License, or (at your option) any later version. |
| 12 | * |
| 13 | * FFmpeg is distributed in the hope that it will be useful, |
| 14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| 16 | * Lesser General Public License for more details. |
| 17 | * |
| 18 | * You should have received a copy of the GNU Lesser General Public |
| 19 | * License along with FFmpeg; if not, write to the Free Software |
| 20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| 21 | */ |
| 22 | |
| 23 | #include "libavutil/intreadwrite.h" |
| 24 | #include "libavutil/log.h" |
| 25 | #include "avcodec.h" |
| 26 | #include "internal.h" |
| 27 | #include "mathops.h" |
| 28 | |
| 29 | #define AES3_HEADER_LEN 4 |
| 30 | |
| 31 | static int s302m_parse_frame_header(AVCodecContext *avctx, const uint8_t *buf, |
| 32 | int buf_size) |
| 33 | { |
| 34 | uint32_t h; |
| 35 | int frame_size, channels, bits; |
| 36 | |
| 37 | if (buf_size <= AES3_HEADER_LEN) { |
| 38 | av_log(avctx, AV_LOG_ERROR, "frame is too short\n"); |
| 39 | return AVERROR_INVALIDDATA; |
| 40 | } |
| 41 | |
| 42 | /* |
| 43 | * AES3 header : |
| 44 | * size: 16 |
| 45 | * number channels 2 |
| 46 | * channel_id 8 |
| 47 | * bits per samples 2 |
| 48 | * alignments 4 |
| 49 | */ |
| 50 | |
| 51 | h = AV_RB32(buf); |
| 52 | frame_size = (h >> 16) & 0xffff; |
| 53 | channels = ((h >> 14) & 0x0003) * 2 + 2; |
| 54 | bits = ((h >> 4) & 0x0003) * 4 + 16; |
| 55 | |
| 56 | if (AES3_HEADER_LEN + frame_size != buf_size || bits > 24) { |
| 57 | av_log(avctx, AV_LOG_ERROR, "frame has invalid header\n"); |
| 58 | return AVERROR_INVALIDDATA; |
| 59 | } |
| 60 | |
| 61 | /* Set output properties */ |
| 62 | avctx->bits_per_raw_sample = bits; |
| 63 | if (bits > 16) |
| 64 | avctx->sample_fmt = AV_SAMPLE_FMT_S32; |
| 65 | else |
| 66 | avctx->sample_fmt = AV_SAMPLE_FMT_S16; |
| 67 | |
| 68 | avctx->channels = channels; |
| 69 | switch(channels) { |
| 70 | case 2: |
| 71 | avctx->channel_layout = AV_CH_LAYOUT_STEREO; |
| 72 | break; |
| 73 | case 4: |
| 74 | avctx->channel_layout = AV_CH_LAYOUT_QUAD; |
| 75 | break; |
| 76 | case 6: |
| 77 | avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK; |
| 78 | break; |
| 79 | case 8: |
| 80 | avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK | AV_CH_LAYOUT_STEREO_DOWNMIX; |
| 81 | } |
| 82 | avctx->sample_rate = 48000; |
| 83 | avctx->bit_rate = 48000 * avctx->channels * (avctx->bits_per_raw_sample + 4) + |
| 84 | 32 * (48000 / (buf_size * 8 / |
| 85 | (avctx->channels * |
| 86 | (avctx->bits_per_raw_sample + 4)))); |
| 87 | |
| 88 | return frame_size; |
| 89 | } |
| 90 | |
| 91 | static int s302m_decode_frame(AVCodecContext *avctx, void *data, |
| 92 | int *got_frame_ptr, AVPacket *avpkt) |
| 93 | { |
| 94 | AVFrame *frame = data; |
| 95 | const uint8_t *buf = avpkt->data; |
| 96 | int buf_size = avpkt->size; |
| 97 | int block_size, ret; |
| 98 | |
| 99 | int frame_size = s302m_parse_frame_header(avctx, buf, buf_size); |
| 100 | if (frame_size < 0) |
| 101 | return frame_size; |
| 102 | |
| 103 | buf_size -= AES3_HEADER_LEN; |
| 104 | buf += AES3_HEADER_LEN; |
| 105 | |
| 106 | /* get output buffer */ |
| 107 | block_size = (avctx->bits_per_raw_sample + 4) / 4; |
| 108 | frame->nb_samples = 2 * (buf_size / block_size) / avctx->channels; |
| 109 | if ((ret = ff_get_buffer(avctx, frame, 0)) < 0) |
| 110 | return ret; |
| 111 | |
| 112 | buf_size = (frame->nb_samples * avctx->channels / 2) * block_size; |
| 113 | |
| 114 | if (avctx->bits_per_raw_sample == 24) { |
| 115 | uint32_t *o = (uint32_t *)frame->data[0]; |
| 116 | for (; buf_size > 6; buf_size -= 7) { |
| 117 | *o++ = (ff_reverse[buf[2]] << 24) | |
| 118 | (ff_reverse[buf[1]] << 16) | |
| 119 | (ff_reverse[buf[0]] << 8); |
| 120 | *o++ = (ff_reverse[buf[6] & 0xf0] << 28) | |
| 121 | (ff_reverse[buf[5]] << 20) | |
| 122 | (ff_reverse[buf[4]] << 12) | |
| 123 | (ff_reverse[buf[3] & 0x0f] << 4); |
| 124 | buf += 7; |
| 125 | } |
| 126 | } else if (avctx->bits_per_raw_sample == 20) { |
| 127 | uint32_t *o = (uint32_t *)frame->data[0]; |
| 128 | for (; buf_size > 5; buf_size -= 6) { |
| 129 | *o++ = (ff_reverse[buf[2] & 0xf0] << 28) | |
| 130 | (ff_reverse[buf[1]] << 20) | |
| 131 | (ff_reverse[buf[0]] << 12); |
| 132 | *o++ = (ff_reverse[buf[5] & 0xf0] << 28) | |
| 133 | (ff_reverse[buf[4]] << 20) | |
| 134 | (ff_reverse[buf[3]] << 12); |
| 135 | buf += 6; |
| 136 | } |
| 137 | } else { |
| 138 | uint16_t *o = (uint16_t *)frame->data[0]; |
| 139 | for (; buf_size > 4; buf_size -= 5) { |
| 140 | *o++ = (ff_reverse[buf[1]] << 8) | |
| 141 | ff_reverse[buf[0]]; |
| 142 | *o++ = (ff_reverse[buf[4] & 0xf0] << 12) | |
| 143 | (ff_reverse[buf[3]] << 4) | |
| 144 | (ff_reverse[buf[2]] >> 4); |
| 145 | buf += 5; |
| 146 | } |
| 147 | } |
| 148 | |
| 149 | *got_frame_ptr = 1; |
| 150 | |
| 151 | return avpkt->size; |
| 152 | } |
| 153 | |
| 154 | AVCodec ff_s302m_decoder = { |
| 155 | .name = "s302m", |
| 156 | .long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"), |
| 157 | .type = AVMEDIA_TYPE_AUDIO, |
| 158 | .id = AV_CODEC_ID_S302M, |
| 159 | .decode = s302m_decode_frame, |
| 160 | .capabilities = CODEC_CAP_DR1, |
| 161 | }; |