PeerStreamer

/*

 * RTP/Quicktime support.

 * Copyright (c) 2009 Ronald S. Bultje

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg is free software; you can redistribute it and/or

 * modify it under the terms of the GNU Lesser General Public

 * License as published by the Free Software Foundation; either

 * version 2.1 of the License, or (at your option) any later version.

 *

 * FFmpeg is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * Lesser General Public License for more details.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * @brief Quicktime-style RTP support

 * @author Ronald S. Bultje <rbultje@ronald.bitfreak.net>

 */

#include "avformat.h"

#include "avio_internal.h"

#include "rtp.h"

#include "rtpdec.h"

#include "isom.h"

#include "libavcodec/get_bits.h"

struct PayloadContext {

    AVPacket pkt;

    int bytes_per_frame, remaining;

    uint32_t timestamp;

};

static int qt_rtp_parse_packet(AVFormatContext *s, PayloadContext *qt,

                               AVStream *st, AVPacket *pkt,

                               uint32_t *timestamp, const uint8_t *buf,

                               int len, int flags)

{

    AVIOContext pb;

    GetBitContext gb;

    int packing_scheme, has_payload_desc, has_packet_info, alen,

        has_marker_bit = flags & RTP_FLAG_MARKER;

    if (qt->remaining) {

        int num = qt->pkt.size / qt->bytes_per_frame;

        if (av_new_packet(pkt, qt->bytes_per_frame))

            return AVERROR(ENOMEM);

        pkt->stream_index = st->index;

        pkt->flags        = qt->pkt.flags;

        memcpy(pkt->data,

               &qt->pkt.data[(num - qt->remaining) * qt->bytes_per_frame],

               qt->bytes_per_frame);

        if (--qt->remaining == 0) {

            av_freep(&qt->pkt.data);

            qt->pkt.size = 0;

        }

        return qt->remaining > 0;

    }

    /**

     * The RTP payload is described in:

     * http://developer.apple.com/quicktime/icefloe/dispatch026.html

     */

    init_get_bits(&gb, buf, len << 3);

    ffio_init_context(&pb, buf, len, 0, NULL, NULL, NULL, NULL);

    if (len < 4)

        return AVERROR_INVALIDDATA;

    skip_bits(&gb, 4); // version

    if ((packing_scheme = get_bits(&gb, 2)) == 0)

        return AVERROR_INVALIDDATA;

    if (get_bits1(&gb))

        flags          |= RTP_FLAG_KEY;

    has_payload_desc    = get_bits1(&gb);

    has_packet_info     = get_bits1(&gb);

    skip_bits(&gb, 23); // reserved:7, cache payload info:1, payload ID:15

    if (has_payload_desc) {

        int data_len, pos, is_start, is_finish;

        uint32_t tag;

        pos = get_bits_count(&gb) >> 3;

        if (pos + 12 > len)

            return AVERROR_INVALIDDATA;

        skip_bits(&gb, 2); // has non-I frames:1, is sparse:1

        is_start  = get_bits1(&gb);

        is_finish = get_bits1(&gb);

        if (!is_start || !is_finish) {

            av_log_missing_feature(s, "RTP-X-QT with payload description "

                                      "split over several packets", 1);

            return AVERROR_NOTSUPP;

        }

        skip_bits(&gb, 12); // reserved

        data_len = get_bits(&gb, 16);

        avio_seek(&pb, pos + 4, SEEK_SET);

        tag = avio_rl32(&pb);

        if ((st->codec->codec_type == AVMEDIA_TYPE_VIDEO &&

                 tag != MKTAG('v','i','d','e')) ||

            (st->codec->codec_type == AVMEDIA_TYPE_AUDIO &&

                 tag != MKTAG('s','o','u','n')))

            return AVERROR_INVALIDDATA;

        av_set_pts_info(st, 32, 1, avio_rb32(&pb));

        if (pos + data_len > len)

            return AVERROR_INVALIDDATA;

        /* TLVs */

        while (avio_tell(&pb) + 4 < pos + data_len) {

            int tlv_len = avio_rb16(&pb);

            tag = avio_rl16(&pb);

            if (avio_tell(&pb) + tlv_len > pos + data_len)

                return AVERROR_INVALIDDATA;

#define MKTAG16(a,b) MKTAG(a,b,0,0)

            switch (tag) {

            case MKTAG16('s','d'): {

                MOVStreamContext *msc;

                void *priv_data = st->priv_data;

                int nb_streams = s->nb_streams;

                MOVContext *mc = av_mallocz(sizeof(*mc));

                if (!mc)

                    return AVERROR(ENOMEM);

                mc->fc = s;

                st->priv_data = msc = av_mallocz(sizeof(MOVStreamContext));

                if (!msc) {

                    av_free(mc);

                    st->priv_data = priv_data;

                    return AVERROR(ENOMEM);

                }

                /* ff_mov_read_stsd_entries updates stream s->nb_streams-1,

                 * so set it temporarily to indicate which stream to update. */

                s->nb_streams = st->index + 1;

                ff_mov_read_stsd_entries(mc, &pb, 1);

                qt->bytes_per_frame = msc->bytes_per_frame;

                av_free(msc);

                av_free(mc);

                st->priv_data = priv_data;

                s->nb_streams = nb_streams;

                break;

            }

            default:

                avio_skip(&pb, tlv_len);

                break;

            }

        }

        /* 32-bit alignment */

        avio_skip(&pb, ((avio_tell(&pb) + 3) & ~3) - avio_tell(&pb));

    } else

        avio_seek(&pb, 4, SEEK_SET);

    if (has_packet_info) {

        av_log_missing_feature(s, "RTP-X-QT with packet specific info", 1);

        return AVERROR_NOTSUPP;

    }

    alen = len - avio_tell(&pb);

    if (alen <= 0)

        return AVERROR_INVALIDDATA;

    switch (packing_scheme) {

    case 3: /* one data packet spread over 1 or multiple RTP packets */

        if (qt->pkt.size > 0 && qt->timestamp == *timestamp) {

            qt->pkt.data = av_realloc(qt->pkt.data, qt->pkt.size + alen +

                                      FF_INPUT_BUFFER_PADDING_SIZE);

        } else {

            av_freep(&qt->pkt.data);

            av_init_packet(&qt->pkt);

            qt->pkt.data = av_malloc(alen + FF_INPUT_BUFFER_PADDING_SIZE);

            qt->pkt.size = 0;

            qt->timestamp = *timestamp;

        }

        if (!qt->pkt.data)

            return AVERROR(ENOMEM);

        memcpy(qt->pkt.data + qt->pkt.size, buf + avio_tell(&pb), alen);

        qt->pkt.size += alen;

        if (has_marker_bit) {

            *pkt = qt->pkt;

            qt->pkt.size = 0;

            qt->pkt.data = NULL;

            pkt->flags        = flags & RTP_FLAG_KEY ? AV_PKT_FLAG_KEY : 0;

            pkt->stream_index = st->index;

            pkt->destruct     = av_destruct_packet;

            memset(pkt->data + pkt->size, 0, FF_INPUT_BUFFER_PADDING_SIZE);

            return 0;

        }

        return AVERROR(EAGAIN);

    case 1: /* constant packet size, multiple packets per RTP packet */

        if (qt->bytes_per_frame == 0 ||

            alen % qt->bytes_per_frame != 0)

            return AVERROR_INVALIDDATA; /* wrongly padded */

        qt->remaining = (alen / qt->bytes_per_frame) - 1;

        if (av_new_packet(pkt, qt->bytes_per_frame))

            return AVERROR(ENOMEM);

        memcpy(pkt->data, buf + avio_tell(&pb), qt->bytes_per_frame);

        pkt->flags = flags & RTP_FLAG_KEY ? AV_PKT_FLAG_KEY : 0;

        pkt->stream_index = st->index;

        if (qt->remaining > 0) {

            av_freep(&qt->pkt.data);

            qt->pkt.data = av_malloc(qt->remaining * qt->bytes_per_frame);

            if (!qt->pkt.data) {

                av_free_packet(pkt);

                return AVERROR(ENOMEM);

            }

            qt->pkt.size = qt->remaining * qt->bytes_per_frame;

            memcpy(qt->pkt.data,

                   buf + avio_tell(&pb) + qt->bytes_per_frame,

                   qt->remaining * qt->bytes_per_frame);

            qt->pkt.flags = pkt->flags;

            return 1;

        }

        return 0;

    default:  /* unimplemented */

        av_log_missing_feature(NULL, "RTP-X-QT with packing scheme 2", 1);

        return AVERROR_NOTSUPP;

    }

}

static PayloadContext *qt_rtp_new(void)

{

    return av_mallocz(sizeof(PayloadContext));

}

static void qt_rtp_free(PayloadContext *qt)

{

    av_freep(&qt->pkt.data);

    av_free(qt);

}

#define RTP_QT_HANDLER(m, n, s, t) \

RTPDynamicProtocolHandler ff_ ## m ## _rtp_ ## n ## _handler = { \

    .enc_name         = s, \

    .codec_type       = t, \

    .codec_id         = CODEC_ID_NONE, \

    .open             = qt_rtp_new,    \

    .close            = qt_rtp_free,   \

    .parse_packet     = qt_rtp_parse_packet, \

}

RTP_QT_HANDLER(qt,        vid, "X-QT",        AVMEDIA_TYPE_VIDEO);

RTP_QT_HANDLER(qt,        aud, "X-QT",        AVMEDIA_TYPE_AUDIO);

RTP_QT_HANDLER(quicktime, vid, "X-QUICKTIME", AVMEDIA_TYPE_VIDEO);

RTP_QT_HANDLER(quicktime, aud, "X-QUICKTIME", AVMEDIA_TYPE_AUDIO);