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ffmpeg / libavformat / rtpdec_qcelp.c @ 9261e6cf

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/**
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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 Libav.
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 *
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 * Libav 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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 * Libav 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 Libav; 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 "rtpdec_formats.h"
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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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typedef struct {
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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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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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    /* 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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static PayloadContext *qcelp_new_context(void)
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{
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    return av_mallocz(sizeof(PayloadContext));
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}
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static void qcelp_free_context(PayloadContext *data)
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{
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    av_free(data);
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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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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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    if (len < 2)
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        return AVERROR_INVALIDDATA;
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    interleave_size  = buf[0] >> 3 & 7;
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    interleave_index = buf[0]      & 7;
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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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    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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            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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            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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    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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    if (len - 1 - frame_size > sizeof(data->group[0].data))
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        return AVERROR_INVALIDDATA;
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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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    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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    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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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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    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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    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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        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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        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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    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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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, 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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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           = CODEC_ID_QCELP,
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    .static_payload_id  = 12,
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    .alloc              = qcelp_new_context,
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    .free               = qcelp_free_context,
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    .parse_packet       = qcelp_parse_packet
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};