This source file includes following definitions.
- s302m_parse_frame_header
- s302m_decode_frame
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/log.h"
#include "avcodec.h"
#include "internal.h"
#include "mathops.h"
#define AES3_HEADER_LEN 4
typedef struct S302Context {
AVClass *class;
int non_pcm_mode;
} S302Context;
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;
}
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;
}
avctx->bits_per_raw_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 6:
avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK;
break;
case 8:
avctx->channel_layout = AV_CH_LAYOUT_5POINT1_BACK | AV_CH_LAYOUT_STEREO_DOWNMIX;
}
return frame_size;
}
static int s302m_decode_frame(AVCodecContext *avctx, void *data,
int *got_frame_ptr, AVPacket *avpkt)
{
S302Context *s = avctx->priv_data;
AVFrame *frame = data;
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
int block_size, ret;
int i;
int non_pcm_data_type = -1;
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;
block_size = (avctx->bits_per_raw_sample + 4) / 4;
frame->nb_samples = 2 * (buf_size / block_size) / avctx->channels;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
avctx->bit_rate = 48000 * avctx->channels * (avctx->bits_per_raw_sample + 4) +
32 * 48000 / frame->nb_samples;
buf_size = (frame->nb_samples * avctx->channels / 2) * block_size;
if (avctx->bits_per_raw_sample == 24) {
uint32_t *o = (uint32_t *)frame->data[0];
for (; buf_size > 6; buf_size -= 7) {
*o++ = ((unsigned)ff_reverse[buf[2]] << 24) |
(ff_reverse[buf[1]] << 16) |
(ff_reverse[buf[0]] << 8);
*o++ = ((unsigned)ff_reverse[buf[6] & 0xf0] << 28) |
(ff_reverse[buf[5]] << 20) |
(ff_reverse[buf[4]] << 12) |
(ff_reverse[buf[3] & 0x0f] << 4);
buf += 7;
}
o = (uint32_t *)frame->data[0];
if (avctx->channels == 2)
for (i=0; i<frame->nb_samples * 2 - 6; i+=2) {
if (o[i] || o[i+1] || o[i+2] || o[i+3])
break;
if (o[i+4] == 0x96F87200U && o[i+5] == 0xA54E1F00) {
non_pcm_data_type = (o[i+6] >> 16) & 0x1F;
break;
}
}
} else if (avctx->bits_per_raw_sample == 20) {
uint32_t *o = (uint32_t *)frame->data[0];
for (; buf_size > 5; buf_size -= 6) {
*o++ = ((unsigned)ff_reverse[buf[2] & 0xf0] << 28) |
(ff_reverse[buf[1]] << 20) |
(ff_reverse[buf[0]] << 12);
*o++ = ((unsigned)ff_reverse[buf[5] & 0xf0] << 28) |
(ff_reverse[buf[4]] << 20) |
(ff_reverse[buf[3]] << 12);
buf += 6;
}
o = (uint32_t *)frame->data[0];
if (avctx->channels == 2)
for (i=0; i<frame->nb_samples * 2 - 6; i+=2) {
if (o[i] || o[i+1] || o[i+2] || o[i+3])
break;
if (o[i+4] == 0x6F872000U && o[i+5] == 0x54E1F000) {
non_pcm_data_type = (o[i+6] >> 16) & 0x1F;
break;
}
}
} else {
uint16_t *o = (uint16_t *)frame->data[0];
for (; buf_size > 4; buf_size -= 5) {
*o++ = (ff_reverse[buf[1]] << 8) |
ff_reverse[buf[0]];
*o++ = (ff_reverse[buf[4] & 0xf0] << 12) |
(ff_reverse[buf[3]] << 4) |
(ff_reverse[buf[2]] >> 4);
buf += 5;
}
o = (uint16_t *)frame->data[0];
if (avctx->channels == 2)
for (i=0; i<frame->nb_samples * 2 - 6; i+=2) {
if (o[i] || o[i+1] || o[i+2] || o[i+3])
break;
if (o[i+4] == 0xF872U && o[i+5] == 0x4E1F) {
non_pcm_data_type = (o[i+6] & 0x1F);
break;
}
}
}
if (non_pcm_data_type != -1) {
if (s->non_pcm_mode == 3) {
av_log(avctx, AV_LOG_ERROR,
"S302 non PCM mode with data type %d not supported\n",
non_pcm_data_type);
return AVERROR_PATCHWELCOME;
}
if (s->non_pcm_mode & 1) {
return avpkt->size;
}
}
avctx->sample_rate = 48000;
*got_frame_ptr = 1;
return avpkt->size;
}
#define FLAGS AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_DECODING_PARAM
static const AVOption s302m_options[] = {
{"non_pcm_mode", "Chooses what to do with NON-PCM", offsetof(S302Context, non_pcm_mode), AV_OPT_TYPE_INT, {.i64 = 3}, 0, 3, FLAGS, "non_pcm_mode"},
{"copy" , "Pass NON-PCM through unchanged" , 0, AV_OPT_TYPE_CONST, {.i64 = 0}, 0, 3, FLAGS, "non_pcm_mode"},
{"drop" , "Drop NON-PCM" , 0, AV_OPT_TYPE_CONST, {.i64 = 1}, 0, 3, FLAGS, "non_pcm_mode"},
{"decode_copy" , "Decode if possible else passthrough", 0, AV_OPT_TYPE_CONST, {.i64 = 2}, 0, 3, FLAGS, "non_pcm_mode"},
{"decode_drop" , "Decode if possible else drop" , 0, AV_OPT_TYPE_CONST, {.i64 = 3}, 0, 3, FLAGS, "non_pcm_mode"},
{NULL}
};
static const AVClass s302m_class = {
.class_name = "SMPTE 302M Decoder",
.item_name = av_default_item_name,
.option = s302m_options,
.version = LIBAVUTIL_VERSION_INT,
};
AVCodec ff_s302m_decoder = {
.name = "s302m",
.long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"),
.type = AVMEDIA_TYPE_AUDIO,
.id = AV_CODEC_ID_S302M,
.priv_data_size = sizeof(S302Context),
.decode = s302m_decode_frame,
.capabilities = AV_CODEC_CAP_DR1,
.priv_class = &s302m_class,
};