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ffmpeg / libavformat / rtpdec_qt.c @ e356fc57

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/*
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 * RTP/Quicktime support.
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 * Copyright (c) 2009 Ronald S. Bultje
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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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 * @file
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 * @brief Quicktime-style RTP support
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 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>
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 */
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#include "avformat.h"
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#include "avio_internal.h"
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#include "rtp.h"
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#include "rtpdec.h"
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#include "isom.h"
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#include "libavcodec/get_bits.h"
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struct PayloadContext {
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    AVPacket pkt;
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    int bytes_per_frame, remaining;
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    uint32_t timestamp;
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};
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static int qt_rtp_parse_packet(AVFormatContext *s, PayloadContext *qt,
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                               AVStream *st, AVPacket *pkt,
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                               uint32_t *timestamp, const uint8_t *buf,
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                               int len, int flags)
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{
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    AVIOContext pb;
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    GetBitContext gb;
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    int packing_scheme, has_payload_desc, has_packet_info, alen,
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        has_marker_bit = flags & RTP_FLAG_MARKER;
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    if (qt->remaining) {
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        int num = qt->pkt.size / qt->bytes_per_frame;
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        if (av_new_packet(pkt, qt->bytes_per_frame))
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            return AVERROR(ENOMEM);
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        pkt->stream_index = st->index;
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        pkt->flags        = qt->pkt.flags;
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        memcpy(pkt->data,
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               &qt->pkt.data[(num - qt->remaining) * qt->bytes_per_frame],
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               qt->bytes_per_frame);
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        if (--qt->remaining == 0) {
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            av_freep(&qt->pkt.data);
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            qt->pkt.size = 0;
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        }
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        return qt->remaining > 0;
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    }
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    /**
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     * The RTP payload is described in:
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     * http://developer.apple.com/quicktime/icefloe/dispatch026.html
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     */
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    init_get_bits(&gb, buf, len << 3);
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    ffio_init_context(&pb, buf, len, 0, NULL, NULL, NULL, NULL);
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    if (len < 4)
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        return AVERROR_INVALIDDATA;
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    skip_bits(&gb, 4); // version
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    if ((packing_scheme = get_bits(&gb, 2)) == 0)
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        return AVERROR_INVALIDDATA;
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    if (get_bits1(&gb))
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        flags          |= RTP_FLAG_KEY;
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    has_payload_desc    = get_bits1(&gb);
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    has_packet_info     = get_bits1(&gb);
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    skip_bits(&gb, 23); // reserved:7, cache payload info:1, payload ID:15
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    if (has_payload_desc) {
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        int data_len, pos, is_start, is_finish;
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        uint32_t tag;
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        pos = get_bits_count(&gb) >> 3;
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        if (pos + 12 > len)
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            return AVERROR_INVALIDDATA;
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        skip_bits(&gb, 2); // has non-I frames:1, is sparse:1
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        is_start  = get_bits1(&gb);
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        is_finish = get_bits1(&gb);
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        if (!is_start || !is_finish) {
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            av_log_missing_feature(s, "RTP-X-QT with payload description "
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                                      "split over several packets", 1);
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            return AVERROR_NOTSUPP;
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        }
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        skip_bits(&gb, 12); // reserved
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        data_len = get_bits(&gb, 16);
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        avio_seek(&pb, pos + 4, SEEK_SET);
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        tag = avio_rl32(&pb);
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        if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&
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                 tag != MKTAG('v','i','d','e')) ||
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            (st->codec->codec_type == AVMEDIA_TYPE_AUDIO &&
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                 tag != MKTAG('s','o','u','n')))
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            return AVERROR_INVALIDDATA;
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        av_set_pts_info(st, 32, 1, avio_rb32(&pb));
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        if (pos + data_len > len)
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            return AVERROR_INVALIDDATA;
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        /* TLVs */
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        while (url_ftell(&pb) + 4 < pos + data_len) {
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            int tlv_len = avio_rb16(&pb);
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            tag = avio_rl16(&pb);
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            if (url_ftell(&pb) + tlv_len > pos + data_len)
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                return AVERROR_INVALIDDATA;
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#define MKTAG16(a,b) MKTAG(a,b,0,0)
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            switch (tag) {
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            case MKTAG16('s','d'): {
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                MOVStreamContext *msc;
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                void *priv_data = st->priv_data;
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                int nb_streams = s->nb_streams;
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                MOVContext *mc = av_mallocz(sizeof(*mc));
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                if (!mc)
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                    return AVERROR(ENOMEM);
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                mc->fc = s;
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                st->priv_data = msc = av_mallocz(sizeof(MOVStreamContext));
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                if (!msc) {
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                    av_free(mc);
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                    st->priv_data = priv_data;
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                    return AVERROR(ENOMEM);
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                }
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                /* ff_mov_read_stsd_entries updates stream s->nb_streams-1,
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                 * so set it temporarily to indicate which stream to update. */
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                s->nb_streams = st->index + 1;
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                ff_mov_read_stsd_entries(mc, &pb, 1);
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                qt->bytes_per_frame = msc->bytes_per_frame;
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                av_free(msc);
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                av_free(mc);
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                st->priv_data = priv_data;
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                s->nb_streams = nb_streams;
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                break;
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            }
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            default:
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                avio_seek(&pb, tlv_len, SEEK_CUR);
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                break;
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            }
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        }
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        /* 32-bit alignment */
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        avio_seek(&pb, ((url_ftell(&pb) + 3) & ~3) - url_ftell(&pb), SEEK_CUR);
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    } else
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        avio_seek(&pb, 4, SEEK_SET);
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    if (has_packet_info) {
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        av_log_missing_feature(s, "RTP-X-QT with packet specific info", 1);
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        return AVERROR_NOTSUPP;
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    }
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    alen = len - url_ftell(&pb);
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    if (alen <= 0)
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        return AVERROR_INVALIDDATA;
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    switch (packing_scheme) {
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    case 3: /* one data packet spread over 1 or multiple RTP packets */
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        if (qt->pkt.size > 0 && qt->timestamp == *timestamp) {
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            qt->pkt.data = av_realloc(qt->pkt.data, qt->pkt.size + alen +
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                                      FF_INPUT_BUFFER_PADDING_SIZE);
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        } else {
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            av_freep(&qt->pkt.data);
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            av_init_packet(&qt->pkt);
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            qt->pkt.data = av_malloc(alen + FF_INPUT_BUFFER_PADDING_SIZE);
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            qt->pkt.size = 0;
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            qt->timestamp = *timestamp;
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        }
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        if (!qt->pkt.data)
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            return AVERROR(ENOMEM);
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        memcpy(qt->pkt.data + qt->pkt.size, buf + url_ftell(&pb), alen);
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        qt->pkt.size += alen;
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        if (has_marker_bit) {
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            *pkt = qt->pkt;
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            qt->pkt.size = 0;
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            qt->pkt.data = NULL;
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            pkt->flags        = flags & RTP_FLAG_KEY ? AV_PKT_FLAG_KEY : 0;
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            pkt->stream_index = st->index;
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            pkt->destruct     = av_destruct_packet;
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            memset(pkt->data + pkt->size, 0, FF_INPUT_BUFFER_PADDING_SIZE);
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            return 0;
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        }
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        return AVERROR(EAGAIN);
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    case 1: /* constant packet size, multiple packets per RTP packet */
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        if (qt->bytes_per_frame == 0 ||
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            alen % qt->bytes_per_frame != 0)
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            return AVERROR_INVALIDDATA; /* wrongly padded */
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        qt->remaining = (alen / qt->bytes_per_frame) - 1;
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        if (av_new_packet(pkt, qt->bytes_per_frame))
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            return AVERROR(ENOMEM);
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        memcpy(pkt->data, buf + url_ftell(&pb), qt->bytes_per_frame);
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        pkt->flags = flags & RTP_FLAG_KEY ? AV_PKT_FLAG_KEY : 0;
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        pkt->stream_index = st->index;
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        if (qt->remaining > 0) {
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            av_freep(&qt->pkt.data);
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            qt->pkt.data = av_malloc(qt->remaining * qt->bytes_per_frame);
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            if (!qt->pkt.data) {
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                av_free_packet(pkt);
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                return AVERROR(ENOMEM);
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            }
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            qt->pkt.size = qt->remaining * qt->bytes_per_frame;
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            memcpy(qt->pkt.data,
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                   buf + url_ftell(&pb) + qt->bytes_per_frame,
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                   qt->remaining * qt->bytes_per_frame);
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            qt->pkt.flags = pkt->flags;
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            return 1;
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        }
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        return 0;
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    default:  /* unimplemented */
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        av_log_missing_feature(NULL, "RTP-X-QT with packing scheme 2", 1);
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        return AVERROR_NOTSUPP;
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    }
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}
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static PayloadContext *qt_rtp_new(void)
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{
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    return av_mallocz(sizeof(PayloadContext));
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}
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static void qt_rtp_free(PayloadContext *qt)
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{
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    av_freep(&qt->pkt.data);
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    av_free(qt);
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}
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#define RTP_QT_HANDLER(m, n, s, t) \
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RTPDynamicProtocolHandler ff_ ## m ## _rtp_ ## n ## _handler = { \
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    .enc_name         = s, \
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    .codec_type       = t, \
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    .codec_id         = CODEC_ID_NONE, \
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    .open             = qt_rtp_new,    \
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    .close            = qt_rtp_free,   \
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    .parse_packet     = qt_rtp_parse_packet, \
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}
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RTP_QT_HANDLER(qt,        vid, "X-QT",        AVMEDIA_TYPE_VIDEO);
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RTP_QT_HANDLER(qt,        aud, "X-QT",        AVMEDIA_TYPE_AUDIO);
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RTP_QT_HANDLER(quicktime, vid, "X-QUICKTIME", AVMEDIA_TYPE_VIDEO);
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RTP_QT_HANDLER(quicktime, aud, "X-QUICKTIME", AVMEDIA_TYPE_AUDIO);