195 lines
7.3 KiB
C
195 lines
7.3 KiB
C
/*
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* RTP packetization for H.263 video
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* Copyright (c) 2012 Martin Storsjo
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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 "avformat.h"
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#include "rtpenc.h"
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#include "libavcodec/put_bits.h"
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#include "libavcodec/get_bits.h"
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struct H263Info {
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int src;
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int i;
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int u;
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int s;
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int a;
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int pb;
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int tr;
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};
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struct H263State {
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int gobn;
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int mba;
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int hmv1, vmv1, hmv2, vmv2;
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int quant;
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};
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static void send_mode_a(AVFormatContext *s1, const struct H263Info *info,
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const uint8_t *buf, int len, int ebits, int m)
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{
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RTPMuxContext *s = s1->priv_data;
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PutBitContext pb;
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init_put_bits(&pb, s->buf, 32);
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put_bits(&pb, 1, 0); /* F - 0, mode A */
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put_bits(&pb, 1, 0); /* P - 0, normal I/P */
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put_bits(&pb, 3, 0); /* SBIT - 0 bits */
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put_bits(&pb, 3, ebits); /* EBIT */
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put_bits(&pb, 3, info->src); /* SRC - source format */
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put_bits(&pb, 1, info->i); /* I - inter/intra */
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put_bits(&pb, 1, info->u); /* U - unrestricted motion vector */
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put_bits(&pb, 1, info->s); /* S - syntax-baesd arithmetic coding */
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put_bits(&pb, 1, info->a); /* A - advanced prediction */
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put_bits(&pb, 4, 0); /* R - reserved */
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put_bits(&pb, 2, 0); /* DBQ - 0 */
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put_bits(&pb, 3, 0); /* TRB - 0 */
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put_bits(&pb, 8, info->tr); /* TR */
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flush_put_bits(&pb);
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memcpy(s->buf + 4, buf, len);
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ff_rtp_send_data(s1, s->buf, len + 4, m);
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}
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static void send_mode_b(AVFormatContext *s1, const struct H263Info *info,
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const struct H263State *state, const uint8_t *buf,
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int len, int sbits, int ebits, int m)
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{
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RTPMuxContext *s = s1->priv_data;
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PutBitContext pb;
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init_put_bits(&pb, s->buf, 64);
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put_bits(&pb, 1, 1); /* F - 1, mode B */
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put_bits(&pb, 1, 0); /* P - 0, mode B */
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put_bits(&pb, 3, sbits); /* SBIT - 0 bits */
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put_bits(&pb, 3, ebits); /* EBIT - 0 bits */
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put_bits(&pb, 3, info->src); /* SRC - source format */
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put_bits(&pb, 5, state->quant); /* QUANT - quantizer for the first MB */
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put_bits(&pb, 5, state->gobn); /* GOBN - GOB number */
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put_bits(&pb, 9, state->mba); /* MBA - MB address */
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put_bits(&pb, 2, 0); /* R - reserved */
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put_bits(&pb, 1, info->i); /* I - inter/intra */
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put_bits(&pb, 1, info->u); /* U - unrestricted motion vector */
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put_bits(&pb, 1, info->s); /* S - syntax-baesd arithmetic coding */
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put_bits(&pb, 1, info->a); /* A - advanced prediction */
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put_bits(&pb, 7, state->hmv1); /* HVM1 - horizontal motion vector 1 */
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put_bits(&pb, 7, state->vmv1); /* VMV1 - vertical motion vector 1 */
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put_bits(&pb, 7, state->hmv2); /* HVM2 - horizontal motion vector 2 */
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put_bits(&pb, 7, state->vmv2); /* VMV2 - vertical motion vector 2 */
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flush_put_bits(&pb);
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memcpy(s->buf + 8, buf, len);
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ff_rtp_send_data(s1, s->buf, len + 8, m);
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}
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void ff_rtp_send_h263_rfc2190(AVFormatContext *s1, const uint8_t *buf, int size,
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const uint8_t *mb_info, int mb_info_size)
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{
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RTPMuxContext *s = s1->priv_data;
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int len, sbits = 0, ebits = 0;
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GetBitContext gb;
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struct H263Info info = { 0 };
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struct H263State state = { 0 };
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int mb_info_pos = 0, mb_info_count = mb_info_size / 12;
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const uint8_t *buf_base = buf;
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s->timestamp = s->cur_timestamp;
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init_get_bits(&gb, buf, size*8);
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if (get_bits(&gb, 22) == 0x20) { /* Picture Start Code */
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info.tr = get_bits(&gb, 8);
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skip_bits(&gb, 2); /* PTYPE start, H261 disambiguation */
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skip_bits(&gb, 3); /* Split screen, document camera, freeze picture release */
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info.src = get_bits(&gb, 3);
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info.i = get_bits(&gb, 1);
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info.u = get_bits(&gb, 1);
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info.s = get_bits(&gb, 1);
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info.a = get_bits(&gb, 1);
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info.pb = get_bits(&gb, 1);
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}
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while (size > 0) {
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struct H263State packet_start_state = state;
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len = FFMIN(s->max_payload_size - 8, size);
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/* Look for a better place to split the frame into packets. */
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if (len < size) {
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const uint8_t *end = ff_h263_find_resync_marker_reverse(buf,
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buf + len);
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len = end - buf;
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if (len == s->max_payload_size - 8) {
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/* Skip mb info prior to the start of the current ptr */
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while (mb_info_pos < mb_info_count) {
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uint32_t pos = AV_RL32(&mb_info[12*mb_info_pos])/8;
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if (pos >= buf - buf_base)
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break;
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mb_info_pos++;
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}
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/* Find the first mb info past the end pointer */
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while (mb_info_pos + 1 < mb_info_count) {
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uint32_t pos = AV_RL32(&mb_info[12*(mb_info_pos + 1)])/8;
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if (pos >= end - buf_base)
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break;
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mb_info_pos++;
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}
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if (mb_info_pos < mb_info_count) {
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const uint8_t *ptr = &mb_info[12*mb_info_pos];
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/* get position in bits in the input packet at which the next info block should be used */
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uint32_t bit_pos = AV_RL32(ptr);
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/* get position in bytes */
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uint32_t pos_next_mb_info = (bit_pos + 7)/8;
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/* check if data from the next MB info block should be used */
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if (pos_next_mb_info <= end - buf_base) {
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state.quant = ptr[4];
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state.gobn = ptr[5];
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state.mba = AV_RL16(&ptr[6]);
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state.hmv1 = (int8_t) ptr[8];
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state.vmv1 = (int8_t) ptr[9];
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state.hmv2 = (int8_t) ptr[10];
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state.vmv2 = (int8_t) ptr[11];
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ebits = 8 * pos_next_mb_info - bit_pos;
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len = pos_next_mb_info - (buf - buf_base);
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mb_info_pos++;
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}
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} else {
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av_log(s1, AV_LOG_ERROR, "Unable to split H263 packet, "
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"use -mb_info %d or -ps 1.\n",
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s->max_payload_size - 8);
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}
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}
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}
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if (size > 2 && !buf[0] && !buf[1])
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send_mode_a(s1, &info, buf, len, ebits, len == size);
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else
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send_mode_b(s1, &info, &packet_start_state, buf, len, sbits,
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ebits, len == size);
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if (ebits) {
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sbits = 8 - ebits;
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len--;
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} else {
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sbits = 0;
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}
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buf += len;
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size -= len;
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ebits = 0;
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}
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}
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