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FFmpeg/libavcodec/s302m.c
Andreas Rheinhardt 4243da4ff4 avcodec/codec_internal: Use union for FFCodec decode/encode callbacks 
This is possible, because every given FFCodec has to implement
exactly one of these. Doing so decreases sizeof(FFCodec) and
therefore decreases the size of the binary.
Notice that in case of position-independent code the decrease
is in .data.rel.ro, so that this translates to decreased
memory consumption.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com>
2022-04-05 20:02:37 +02:00

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/*
* 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/channel_layout.h"
#include "libavutil/intreadwrite.h"
#include "libavutil/opt.h"
#include "libavutil/log.h"
#include "libavutil/reverse.h"
#include "avcodec.h"
#include "codec_internal.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;
}
/*
* 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_raw_sample = bits;
if (bits > 16)
avctx->sample_fmt = AV_SAMPLE_FMT_S32;
else
avctx->sample_fmt = AV_SAMPLE_FMT_S16;
av_channel_layout_uninit(&avctx->ch_layout);
switch(channels) {
case 2:
avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_STEREO;
break;
case 4:
avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_QUAD;
break;
case 6:
avctx->ch_layout = (AVChannelLayout)AV_CHANNEL_LAYOUT_5POINT1_BACK;
break;
case 8:
av_channel_layout_from_mask(&avctx->ch_layout,
AV_CH_LAYOUT_5POINT1_BACK | AV_CH_LAYOUT_STEREO_DOWNMIX);
break;
default:
avctx->ch_layout.order = AV_CHANNEL_ORDER_UNSPEC;
avctx->ch_layout.nb_channels = channels;
break;
}
return frame_size;
}
static int s302m_decode_frame(AVCodecContext *avctx, AVFrame *frame,
int *got_frame_ptr, AVPacket *avpkt)
{
S302Context *s = avctx->priv_data;
const uint8_t *buf = avpkt->data;
int buf_size = avpkt->size;
int block_size, ret, channels;
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;
/* get output buffer */
block_size = (avctx->bits_per_raw_sample + 4) / 4;
channels = avctx->ch_layout.nb_channels;
frame->nb_samples = 2 * (buf_size / block_size) / channels;
if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
return ret;
avctx->bit_rate = 48000 * channels * (avctx->bits_per_raw_sample + 4) +
32 * 48000 / frame->nb_samples;
buf_size = (frame->nb_samples * 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 (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 (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 (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,
};
const FFCodec ff_s302m_decoder = {
.p.name = "s302m",
.p.long_name = NULL_IF_CONFIG_SMALL("SMPTE 302M"),
.p.type = AVMEDIA_TYPE_AUDIO,
.p.id = AV_CODEC_ID_S302M,
.p.priv_class = &s302m_class,
.priv_data_size = sizeof(S302Context),
FF_CODEC_DECODE_CB(s302m_decode_frame),
.p.capabilities = AV_CODEC_CAP_CHANNEL_CONF |
AV_CODEC_CAP_DR1,
};
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