220 lines
		
	
	
		
			7.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			220 lines
		
	
	
		
			7.5 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
| /*
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|  * RTP Depacketization of QCELP/PureVoice, RFC 2658
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|  * Copyright (c) 2010 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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| 
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| #include "rtpdec_formats.h"
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| 
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| static const uint8_t frame_sizes[] = {
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|     1, 4, 8, 17, 35
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| };
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| 
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| typedef struct InterleavePacket {
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|     int pos;
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|     int size;
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|     /* The largest frame is 35 bytes, only 10 frames are allowed per
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|      * packet, and we return the first one immediately, so allocate
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|      * space for 9 frames */
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|     uint8_t data[35*9];
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| } InterleavePacket;
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| 
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| struct PayloadContext {
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|     int interleave_size;
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|     int interleave_index;
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|     InterleavePacket group[6];
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|     int group_finished;
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| 
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|     /* The maximum packet size, 10 frames of 35 bytes each, and one
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|      * packet header byte. */
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|     uint8_t  next_data[1 + 35*10];
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|     int      next_size;
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|     uint32_t next_timestamp;
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| };
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| 
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| static int return_stored_frame(AVFormatContext *ctx, PayloadContext *data,
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|                                AVStream *st, AVPacket *pkt, uint32_t *timestamp,
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|                                const uint8_t *buf, int len);
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| 
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| static int store_packet(AVFormatContext *ctx, PayloadContext *data,
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|                         AVStream *st, AVPacket *pkt, uint32_t *timestamp,
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|                         const uint8_t *buf, int len)
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| {
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|     int interleave_size, interleave_index;
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|     int frame_size, ret;
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|     InterleavePacket* ip;
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| 
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|     if (len < 2)
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|         return AVERROR_INVALIDDATA;
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| 
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|     interleave_size  = buf[0] >> 3 & 7;
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|     interleave_index = buf[0]      & 7;
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| 
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|     if (interleave_size > 5) {
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|         av_log(ctx, AV_LOG_ERROR, "Invalid interleave size %d\n",
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|                                    interleave_size);
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|         return AVERROR_INVALIDDATA;
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|     }
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|     if (interleave_index > interleave_size) {
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|         av_log(ctx, AV_LOG_ERROR, "Invalid interleave index %d/%d\n",
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|                                    interleave_index, interleave_size);
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|         return AVERROR_INVALIDDATA;
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|     }
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|     if (interleave_size != data->interleave_size) {
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|         int i;
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|         /* First packet, or changed interleave size */
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|         data->interleave_size = interleave_size;
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|         data->interleave_index = 0;
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|         for (i = 0; i < 6; i++)
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|             data->group[i].size = 0;
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|     }
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| 
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|     if (interleave_index < data->interleave_index) {
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|         /* Wrapped around - missed the last packet of the previous group. */
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|         if (data->group_finished) {
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|             /* No more data in the packets in this interleaving group, just
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|              * start processing the next one */
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|             data->interleave_index = 0;
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|         } else {
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|             /* Stash away the current packet, emit everything we have of the
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|              * previous group. */
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|             for (; data->interleave_index <= interleave_size;
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|                  data->interleave_index++)
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|                 data->group[data->interleave_index].size = 0;
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| 
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|             if (len > sizeof(data->next_data))
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|                 return AVERROR_INVALIDDATA;
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|             memcpy(data->next_data, buf, len);
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|             data->next_size = len;
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|             data->next_timestamp = *timestamp;
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|             *timestamp = RTP_NOTS_VALUE;
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| 
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|             data->interleave_index = 0;
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|             return return_stored_frame(ctx, data, st, pkt, timestamp, buf, len);
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|         }
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|     }
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|     if (interleave_index > data->interleave_index) {
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|         /* We missed a packet */
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|         for (; data->interleave_index < interleave_index;
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|              data->interleave_index++)
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|             data->group[data->interleave_index].size = 0;
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|     }
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|     data->interleave_index = interleave_index;
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| 
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|     if (buf[1] >= FF_ARRAY_ELEMS(frame_sizes))
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|         return AVERROR_INVALIDDATA;
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|     frame_size = frame_sizes[buf[1]];
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|     if (1 + frame_size > len)
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|         return AVERROR_INVALIDDATA;
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| 
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|     if (len - 1 - frame_size > sizeof(data->group[0].data))
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|         return AVERROR_INVALIDDATA;
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| 
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|     if ((ret = av_new_packet(pkt, frame_size)) < 0)
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|         return ret;
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|     memcpy(pkt->data, &buf[1], frame_size);
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|     pkt->stream_index = st->index;
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| 
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|     ip = &data->group[data->interleave_index];
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|     ip->size = len - 1 - frame_size;
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|     ip->pos = 0;
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|     memcpy(ip->data, &buf[1 + frame_size], ip->size);
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|     /* Each packet must contain the same number of frames according to the
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|      * RFC. If there's no data left in this packet, there shouldn't be any
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|      * in any of the other frames in the interleaving group either. */
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|     data->group_finished = ip->size == 0;
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| 
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|     if (interleave_index == interleave_size) {
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|         data->interleave_index = 0;
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|         return !data->group_finished;
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|     } else {
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|         data->interleave_index++;
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|         return 0;
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|     }
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| }
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| 
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| static int return_stored_frame(AVFormatContext *ctx, PayloadContext *data,
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|                                AVStream *st, AVPacket *pkt, uint32_t *timestamp,
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|                                const uint8_t *buf, int len)
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| {
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|     InterleavePacket* ip = &data->group[data->interleave_index];
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|     int frame_size, ret;
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| 
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|     if (data->group_finished && data->interleave_index == 0) {
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|         *timestamp = data->next_timestamp;
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|         ret = store_packet(ctx, data, st, pkt, timestamp, data->next_data,
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|                            data->next_size);
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|         data->next_size = 0;
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|         return ret;
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|     }
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| 
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|     if (ip->size == 0) {
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|         /* No stored data for this interleave block, output an empty packet */
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|         if ((ret = av_new_packet(pkt, 1)) < 0)
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|             return ret;
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|         pkt->data[0] = 0; // Blank - could also be 14, Erasure
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|     } else {
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|         if (ip->pos >= ip->size)
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|             return AVERROR_INVALIDDATA;
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|         if (ip->data[ip->pos] >= FF_ARRAY_ELEMS(frame_sizes))
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|             return AVERROR_INVALIDDATA;
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|         frame_size = frame_sizes[ip->data[ip->pos]];
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|         if (ip->pos + frame_size > ip->size)
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|             return AVERROR_INVALIDDATA;
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| 
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|         if ((ret = av_new_packet(pkt, frame_size)) < 0)
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|             return ret;
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|         memcpy(pkt->data, &ip->data[ip->pos], frame_size);
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| 
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|         ip->pos += frame_size;
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|         data->group_finished = ip->pos >= ip->size;
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|     }
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|     pkt->stream_index = st->index;
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| 
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|     if (data->interleave_index == data->interleave_size) {
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|         data->interleave_index = 0;
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|         if (!data->group_finished)
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|             return 1;
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|         else
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|             return data->next_size > 0;
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|     } else {
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|         data->interleave_index++;
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|         return 1;
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|     }
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| }
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| 
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| static int qcelp_parse_packet(AVFormatContext *ctx, PayloadContext *data,
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|                               AVStream *st, AVPacket *pkt, uint32_t *timestamp,
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|                               const uint8_t *buf, int len, uint16_t seq,
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|                               int flags)
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| {
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|     if (buf)
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|         return store_packet(ctx, data, st, pkt, timestamp, buf, len);
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|     else
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|         return return_stored_frame(ctx, data, st, pkt, timestamp, buf, len);
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| }
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| 
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| const RTPDynamicProtocolHandler ff_qcelp_dynamic_handler = {
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|     .enc_name           = "x-Purevoice",
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|     .codec_type         = AVMEDIA_TYPE_AUDIO,
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|     .codec_id           = AV_CODEC_ID_QCELP,
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|     .priv_data_size     = sizeof(PayloadContext),
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|     .static_payload_id  = 12,
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|     .parse_packet       = qcelp_parse_packet,
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| };
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