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00023 #include "libavutil/intreadwrite.h"
00024 #include "avcodec.h"
00025
00026 #define AES3_HEADER_LEN 4
00027
00028 typedef struct S302MDecodeContext {
00029 AVFrame frame;
00030 } S302MDecodeContext;
00031
00032 static int s302m_parse_frame_header(AVCodecContext *avctx, const uint8_t *buf,
00033 int buf_size)
00034 {
00035 uint32_t h;
00036 int frame_size, channels, bits;
00037
00038 if (buf_size <= AES3_HEADER_LEN) {
00039 av_log(avctx, AV_LOG_ERROR, "frame is too short\n");
00040 return AVERROR_INVALIDDATA;
00041 }
00042
00043
00044
00045
00046
00047
00048
00049
00050
00051
00052 h = AV_RB32(buf);
00053 frame_size = (h >> 16) & 0xffff;
00054 channels = ((h >> 14) & 0x0003) * 2 + 2;
00055 bits = ((h >> 4) & 0x0003) * 4 + 16;
00056
00057 if (AES3_HEADER_LEN + frame_size != buf_size || bits > 24) {
00058 av_log(avctx, AV_LOG_ERROR, "frame has invalid header\n");
00059 return AVERROR_INVALIDDATA;
00060 }
00061
00062
00063 avctx->bits_per_coded_sample = bits;
00064 if (bits > 16)
00065 avctx->sample_fmt = AV_SAMPLE_FMT_S32;
00066 else
00067 avctx->sample_fmt = AV_SAMPLE_FMT_S16;
00068
00069 avctx->channels = channels;
00070 avctx->sample_rate = 48000;
00071 avctx->bit_rate = 48000 * avctx->channels * (avctx->bits_per_coded_sample + 4) +
00072 32 * (48000 / (buf_size * 8 /
00073 (avctx->channels *
00074 (avctx->bits_per_coded_sample + 4))));
00075
00076 return frame_size;
00077 }
00078
00079 static int s302m_decode_frame(AVCodecContext *avctx, void *data,
00080 int *got_frame_ptr, AVPacket *avpkt)
00081 {
00082 S302MDecodeContext *s = avctx->priv_data;
00083 const uint8_t *buf = avpkt->data;
00084 int buf_size = avpkt->size;
00085 int block_size, ret;
00086
00087 int frame_size = s302m_parse_frame_header(avctx, buf, buf_size);
00088 if (frame_size < 0)
00089 return frame_size;
00090
00091 buf_size -= AES3_HEADER_LEN;
00092 buf += AES3_HEADER_LEN;
00093
00094
00095 block_size = (avctx->bits_per_coded_sample + 4) / 4;
00096 s->frame.nb_samples = 2 * (buf_size / block_size) / avctx->channels;
00097 if ((ret = avctx->get_buffer(avctx, &s->frame)) < 0) {
00098 av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
00099 return ret;
00100 }
00101
00102 buf_size = (s->frame.nb_samples * avctx->channels / 2) * block_size;
00103
00104 if (avctx->bits_per_coded_sample == 24) {
00105 uint32_t *o = (uint32_t *)s->frame.data[0];
00106 for (; buf_size > 6; buf_size -= 7) {
00107 *o++ = (av_reverse[buf[2]] << 24) |
00108 (av_reverse[buf[1]] << 16) |
00109 (av_reverse[buf[0]] << 8);
00110 *o++ = (av_reverse[buf[6] & 0xf0] << 28) |
00111 (av_reverse[buf[5]] << 20) |
00112 (av_reverse[buf[4]] << 12) |
00113 (av_reverse[buf[3] & 0x0f] << 4);
00114 buf += 7;
00115 }
00116 } else if (avctx->bits_per_coded_sample == 20) {
00117 uint32_t *o = (uint32_t *)s->frame.data[0];
00118 for (; buf_size > 5; buf_size -= 6) {
00119 *o++ = (av_reverse[buf[2] & 0xf0] << 28) |
00120 (av_reverse[buf[1]] << 20) |
00121 (av_reverse[buf[0]] << 12);
00122 *o++ = (av_reverse[buf[5] & 0xf0] << 28) |
00123 (av_reverse[buf[4]] << 20) |
00124 (av_reverse[buf[3]] << 12);
00125 buf += 6;
00126 }
00127 } else {
00128 uint16_t *o = (uint16_t *)s->frame.data[0];
00129 for (; buf_size > 4; buf_size -= 5) {
00130 *o++ = (av_reverse[buf[1]] << 8) |
00131 av_reverse[buf[0]];
00132 *o++ = (av_reverse[buf[4] & 0xf0] << 12) |
00133 (av_reverse[buf[3]] << 4) |
00134 (av_reverse[buf[2]] >> 4);
00135 buf += 5;
00136 }
00137 }
00138
00139 *got_frame_ptr = 1;
00140 *(AVFrame *)data = s->frame;
00141
00142 return avpkt->size;
00143 }
00144
00145 static int s302m_decode_init(AVCodecContext *avctx)
00146 {
00147 S302MDecodeContext *s = avctx->priv_data;
00148
00149 avcodec_get_frame_defaults(&s->frame);
00150 avctx->coded_frame = &s->frame;
00151
00152 return 0;
00153 }
00154
00155
00156 AVCodec ff_s302m_decoder = {
00157 .name = "s302m",
00158 .type = AVMEDIA_TYPE_AUDIO,
00159 .id = CODEC_ID_S302M,
00160 .priv_data_size = sizeof(S302MDecodeContext),
00161 .init = s302m_decode_init,
00162 .decode = s302m_decode_frame,
00163 .capabilities = CODEC_CAP_DR1,
00164 .long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"),
00165 };