ffmpeg/libavcodec/truehd_core_bsf.c

185 lines
5.3 KiB
C

/*
* Copyright (c) 2018 Paul B Mahol
*
* 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 "avcodec.h"
#include "bsf.h"
#include "get_bits.h"
#include "mlp_parser.h"
#include "mlp.h"
typedef struct AccessUnit {
uint8_t bits[4];
uint16_t offset;
uint16_t optional;
} AccessUnit;
typedef struct TrueHDCoreContext {
const AVClass *class;
MLPHeaderInfo hdr;
} TrueHDCoreContext;
static int truehd_core_filter(AVBSFContext *ctx, AVPacket *out)
{
TrueHDCoreContext *s = ctx->priv_data;
GetBitContext gbc;
AccessUnit units[MAX_SUBSTREAMS];
AVPacket *in;
int ret, i, size, last_offset = 0;
int in_size, out_size;
int have_header = 0;
int substream_bits = 0;
int start, end;
uint16_t dts;
ret = ff_bsf_get_packet(ctx, &in);
if (ret < 0)
return ret;
if (in->size < 4)
goto fail;
ret = init_get_bits(&gbc, in->data, 32);
if (ret < 0)
goto fail;
skip_bits(&gbc, 4);
in_size = get_bits(&gbc, 12) * 2;
if (in_size < 4 || in_size > in->size)
goto fail;
out_size = in_size;
dts = get_bits(&gbc, 16);
ret = init_get_bits8(&gbc, in->data + 4, in->size - 4);
if (ret < 0)
goto fail;
if (show_bits_long(&gbc, 32) == 0xf8726fba) {
if ((ret = ff_mlp_read_major_sync(ctx, &s->hdr, &gbc)) != 0)
goto fail;
have_header = 1;
}
if (s->hdr.num_substreams > MAX_SUBSTREAMS)
goto fail;
start = get_bits_count(&gbc);
for (i = 0; i < s->hdr.num_substreams; i++) {
for (int j = 0; j < 4; j++)
units[i].bits[j] = get_bits1(&gbc);
units[i].offset = get_bits(&gbc, 12) * 2;
if (i < FFMIN(s->hdr.num_substreams, 3)) {
last_offset = units[i].offset;
substream_bits += 16;
}
if (units[i].bits[0]) {
units[i].optional = get_bits(&gbc, 16);
if (i < FFMIN(s->hdr.num_substreams, 3))
substream_bits += 16;
}
}
end = get_bits_count(&gbc);
size = ((end + 7) >> 3) + 4 + last_offset;
if (size >= 0 && size <= in->size)
out_size = size;
if (out_size < in_size) {
int bpos = 0, reduce = (end - start - substream_bits) >> 4;
uint16_t parity_nibble = 0;
uint16_t auheader;
ret = av_new_packet(out, out_size);
if (ret < 0)
goto fail;
AV_WB16(out->data + 2, dts);
parity_nibble = dts;
out->size -= reduce * 2;
parity_nibble ^= out->size / 2;
if (have_header) {
memcpy(out->data + 4, in->data + 4, 28);
out->data[16 + 4] = (out->data[16 + 4] & 0x0f) | (FFMIN(s->hdr.num_substreams, 3) << 4);
out->data[25 + 4] = out->data[25 + 4] & 0xfe;
out->data[26 + 4] = 0xff;
out->data[27 + 4] = 0xff;
AV_WL16(out->data + 4 + 26, ff_mlp_checksum16(out->data + 4, 26));
}
for (i = 0; i < FFMIN(s->hdr.num_substreams, 3); i++) {
uint16_t substr_hdr = 0;
substr_hdr |= (units[i].bits[0] << 15);
substr_hdr |= (units[i].bits[1] << 14);
substr_hdr |= (units[i].bits[2] << 13);
substr_hdr |= (units[i].bits[3] << 12);
substr_hdr |= (units[i].offset / 2) & 0x0FFF;
AV_WB16(out->data + have_header * 28 + 4 + bpos, substr_hdr);
parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
if (units[i].bits[0]) {
AV_WB16(out->data + have_header * 28 + 4 + bpos, units[i].optional);
parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
parity_nibble ^= out->data[have_header * 28 + 4 + bpos++];
}
}
parity_nibble ^= parity_nibble >> 8;
parity_nibble ^= parity_nibble >> 4;
parity_nibble &= 0xF;
memcpy(out->data + have_header * 28 + 4 + bpos,
in->data + 4 + (end >> 3),
out_size - (4 + (end >> 3)));
auheader = (parity_nibble ^ 0xF) << 12;
auheader |= (out->size / 2) & 0x0fff;
AV_WB16(out->data, auheader);
ret = av_packet_copy_props(out, in);
} else {
av_packet_move_ref(out, in);
}
fail:
if (ret < 0)
av_packet_unref(out);
av_packet_free(&in);
return ret;
}
static const enum AVCodecID codec_ids[] = {
AV_CODEC_ID_TRUEHD, AV_CODEC_ID_NONE,
};
const AVBitStreamFilter ff_truehd_core_bsf = {
.name = "truehd_core",
.priv_data_size = sizeof(TrueHDCoreContext),
.filter = truehd_core_filter,
.codec_ids = codec_ids,
};