mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2024-12-07 11:13:41 +02:00
183 lines
5.0 KiB
C
183 lines
5.0 KiB
C
/*
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* Copyright (c) 2018 Paul B Mahol
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "bsf.h"
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#include "bsf_internal.h"
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#include "get_bits.h"
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#include "mlp_parse.h"
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#include "mlp.h"
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typedef struct AccessUnit {
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uint8_t bits[4];
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uint16_t offset;
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uint16_t optional;
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} AccessUnit;
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typedef struct TrueHDCoreContext {
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MLPHeaderInfo hdr;
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} TrueHDCoreContext;
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static int truehd_core_filter(AVBSFContext *ctx, AVPacket *pkt)
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{
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TrueHDCoreContext *s = ctx->priv_data;
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GetBitContext gbc;
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AccessUnit units[MAX_SUBSTREAMS];
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int ret, i, last_offset = 0;
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int in_size, out_size;
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int have_header = 0;
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int substream_bytes = 0;
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int end;
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ret = ff_bsf_get_packet_ref(ctx, pkt);
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if (ret < 0)
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return ret;
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if (pkt->size < 4) {
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ret = AVERROR_INVALIDDATA;
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goto fail;
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}
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in_size = (AV_RB16(pkt->data) & 0xFFF) * 2;
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if (in_size < 4 || in_size > pkt->size) {
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ret = AVERROR_INVALIDDATA;
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goto fail;
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}
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ret = init_get_bits8(&gbc, pkt->data + 4, pkt->size - 4);
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if (ret < 0)
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goto fail;
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if (show_bits_long(&gbc, 32) == 0xf8726fba) {
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if ((ret = ff_mlp_read_major_sync(ctx, &s->hdr, &gbc)) < 0)
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goto fail;
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have_header = 1;
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}
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if (s->hdr.num_substreams > MAX_SUBSTREAMS) {
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ret = AVERROR_INVALIDDATA;
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goto fail;
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}
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for (i = 0; i < s->hdr.num_substreams; i++) {
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for (int j = 0; j < 4; j++)
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units[i].bits[j] = get_bits1(&gbc);
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units[i].offset = get_bits(&gbc, 12);
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if (i < 3) {
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last_offset = units[i].offset * 2;
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substream_bytes += 2;
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}
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if (units[i].bits[0]) {
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units[i].optional = get_bits(&gbc, 16);
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if (i < 3)
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substream_bytes += 2;
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}
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}
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end = get_bits_count(&gbc) >> 3;
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out_size = end + 4 + last_offset;
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if (out_size < in_size) {
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int bpos = 0, reduce = end - have_header * 28 - substream_bytes;
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uint16_t parity_nibble, dts = AV_RB16(pkt->data + 2);
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uint16_t auheader;
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uint8_t header[28];
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av_assert1(reduce >= 0 && reduce % 2 == 0);
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if (have_header) {
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memcpy(header, pkt->data + 4, 28);
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header[16] = (header[16] & 0x0c) | (FFMIN(s->hdr.num_substreams, 3) << 4);
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header[17] &= 0x7f;
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header[25] &= 0xfe;
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AV_WL16(header + 26, ff_mlp_checksum16(header, 26));
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}
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pkt->data += reduce;
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out_size -= reduce;
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pkt->size = out_size;
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ret = av_packet_make_writable(pkt);
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if (ret < 0)
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goto fail;
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AV_WB16(pkt->data + 2, dts);
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parity_nibble = dts;
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parity_nibble ^= out_size / 2;
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for (i = 0; i < FFMIN(s->hdr.num_substreams, 3); i++) {
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uint16_t substr_hdr = 0;
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substr_hdr |= (units[i].bits[0] << 15);
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substr_hdr |= (units[i].bits[1] << 14);
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substr_hdr |= (units[i].bits[2] << 13);
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substr_hdr |= (units[i].bits[3] << 12);
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substr_hdr |= units[i].offset;
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AV_WB16(pkt->data + have_header * 28 + 4 + bpos, substr_hdr);
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parity_nibble ^= substr_hdr;
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bpos += 2;
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if (units[i].bits[0]) {
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AV_WB16(pkt->data + have_header * 28 + 4 + bpos, units[i].optional);
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parity_nibble ^= units[i].optional;
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bpos += 2;
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}
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}
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parity_nibble ^= parity_nibble >> 8;
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parity_nibble ^= parity_nibble >> 4;
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parity_nibble &= 0xF;
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auheader = (parity_nibble ^ 0xF) << 12;
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auheader |= (out_size / 2) & 0x0fff;
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AV_WB16(pkt->data, auheader);
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if (have_header)
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memcpy(pkt->data + 4, header, 28);
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}
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fail:
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if (ret < 0)
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av_packet_unref(pkt);
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return ret;
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}
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static void truehd_core_flush(AVBSFContext *ctx)
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{
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TrueHDCoreContext *s = ctx->priv_data;
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memset(&s->hdr, 0, sizeof(s->hdr));
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}
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static const enum AVCodecID codec_ids[] = {
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AV_CODEC_ID_TRUEHD, AV_CODEC_ID_NONE,
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};
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const AVBitStreamFilter ff_truehd_core_bsf = {
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.name = "truehd_core",
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.priv_data_size = sizeof(TrueHDCoreContext),
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.filter = truehd_core_filter,
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.flush = truehd_core_flush,
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.codec_ids = codec_ids,
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};
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