PeerStreamer

/*

 * RTP output format

 * Copyright (c) 2002 Fabrice Bellard

 *

 * 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

 */

#include "libavcodec/get_bits.h"

#include "avformat.h"

#include "mpegts.h"

#include <unistd.h>

#include "network.h"

#include "rtpenc.h"

//#define DEBUG

#define RTCP_SR_SIZE 28

#define NTP_OFFSET 2208988800ULL

#define NTP_OFFSET_US (NTP_OFFSET * 1000000ULL)

static uint64_t ntp_time(void)

{

  return (av_gettime() / 1000) * 1000 + NTP_OFFSET_US;

}

static int is_supported(enum CodecID id)

{

    switch(id) {

    case CODEC_ID_H263:

    case CODEC_ID_H263P:

    case CODEC_ID_H264:

    case CODEC_ID_MPEG1VIDEO:

    case CODEC_ID_MPEG2VIDEO:

    case CODEC_ID_MPEG4:

    case CODEC_ID_AAC:

    case CODEC_ID_MP2:

    case CODEC_ID_MP3:

    case CODEC_ID_PCM_ALAW:

    case CODEC_ID_PCM_MULAW:

    case CODEC_ID_PCM_S8:

    case CODEC_ID_PCM_S16BE:

    case CODEC_ID_PCM_S16LE:

    case CODEC_ID_PCM_U16BE:

    case CODEC_ID_PCM_U16LE:

    case CODEC_ID_PCM_U8:

    case CODEC_ID_MPEG2TS:

    case CODEC_ID_AMR_NB:

    case CODEC_ID_AMR_WB:

        return 1;

    default:

        return 0;

    }

}

static int rtp_write_header(AVFormatContext *s1)

{

    RTPMuxContext *s = s1->priv_data;

    int payload_type, max_packet_size, n;

    AVStream *st;

    if (s1->nb_streams != 1)

        return -1;

    st = s1->streams[0];

    if (!is_supported(st->codec->codec_id)) {

        av_log(s1, AV_LOG_ERROR, "Unsupported codec %x\n", st->codec->codec_id);

        return -1;

    }

    payload_type = ff_rtp_get_payload_type(st->codec);

    if (payload_type < 0)

        payload_type = RTP_PT_PRIVATE; /* private payload type */

    s->payload_type = payload_type;

// following 2 FIXMEs could be set based on the current time, there is normally no info leak, as RTP will likely be transmitted immediately

    s->base_timestamp = 0; /* FIXME: was random(), what should this be? */

    s->timestamp = s->base_timestamp;

    s->cur_timestamp = 0;

    s->ssrc = 0; /* FIXME: was random(), what should this be? */

    s->first_packet = 1;

    s->first_rtcp_ntp_time = AV_NOPTS_VALUE;

    max_packet_size = url_fget_max_packet_size(s1->pb);

    if (max_packet_size <= 12)

        return AVERROR(EIO);

    s->buf = av_malloc(max_packet_size);

    if (s->buf == NULL) {

        return AVERROR(ENOMEM);

    }

    s->max_payload_size = max_packet_size - 12;

    s->max_frames_per_packet = 0;

    if (s1->max_delay) {

        if (st->codec->codec_type == CODEC_TYPE_AUDIO) {

            if (st->codec->frame_size == 0) {

                av_log(s1, AV_LOG_ERROR, "Cannot respect max delay: frame size = 0\n");

            } else {

                s->max_frames_per_packet = av_rescale_rnd(s1->max_delay, st->codec->sample_rate, AV_TIME_BASE * st->codec->frame_size, AV_ROUND_DOWN);

            }

        }

        if (st->codec->codec_type == CODEC_TYPE_VIDEO) {

            /* FIXME: We should round down here... */

            s->max_frames_per_packet = av_rescale_q(s1->max_delay, (AVRational){1, 1000000}, st->codec->time_base);

        }

    }

    av_set_pts_info(st, 32, 1, 90000);

    switch(st->codec->codec_id) {

    case CODEC_ID_MP2:

    case CODEC_ID_MP3:

        s->buf_ptr = s->buf + 4;

        break;

    case CODEC_ID_MPEG1VIDEO:

    case CODEC_ID_MPEG2VIDEO:

        break;

    case CODEC_ID_MPEG2TS:

        n = s->max_payload_size / TS_PACKET_SIZE;

        if (n < 1)

            n = 1;

        s->max_payload_size = n * TS_PACKET_SIZE;

        s->buf_ptr = s->buf;

        break;

    case CODEC_ID_AMR_NB:

    case CODEC_ID_AMR_WB:

        if (!s->max_frames_per_packet)

            s->max_frames_per_packet = 12;

        if (st->codec->codec_id == CODEC_ID_AMR_NB)

            n = 31;

        else

            n = 61;

        /* max_header_toc_size + the largest AMR payload must fit */

        if (1 + s->max_frames_per_packet + n > s->max_payload_size) {

            av_log(s1, AV_LOG_ERROR, "RTP max payload size too small for AMR\n");

            return -1;

        }

        if (st->codec->channels != 1) {

            av_log(s1, AV_LOG_ERROR, "Only mono is supported\n");

            return -1;

        }

    case CODEC_ID_AAC:

        s->num_frames = 0;

    default:

        if (st->codec->codec_type == CODEC_TYPE_AUDIO) {

            av_set_pts_info(st, 32, 1, st->codec->sample_rate);

        }

        s->buf_ptr = s->buf;

        break;

    }

    return 0;

}

/* send an rtcp sender report packet */

static void rtcp_send_sr(AVFormatContext *s1, int64_t ntp_time)

{

    RTPMuxContext *s = s1->priv_data;

    uint32_t rtp_ts;

    dprintf(s1, "RTCP: %02x %"PRIx64" %x\n", s->payload_type, ntp_time, s->timestamp);

    if (s->first_rtcp_ntp_time == AV_NOPTS_VALUE) s->first_rtcp_ntp_time = ntp_time;

    s->last_rtcp_ntp_time = ntp_time;

    rtp_ts = av_rescale_q(ntp_time - s->first_rtcp_ntp_time, (AVRational){1, 1000000},

                          s1->streams[0]->time_base) + s->base_timestamp;

    put_byte(s1->pb, (RTP_VERSION << 6));

    put_byte(s1->pb, 200);

    put_be16(s1->pb, 6); /* length in words - 1 */

    put_be32(s1->pb, s->ssrc);

    put_be32(s1->pb, ntp_time / 1000000);

    put_be32(s1->pb, ((ntp_time % 1000000) << 32) / 1000000);

    put_be32(s1->pb, rtp_ts);

    put_be32(s1->pb, s->packet_count);

    put_be32(s1->pb, s->octet_count);

    put_flush_packet(s1->pb);

}

/* send an rtp packet. sequence number is incremented, but the caller

   must update the timestamp itself */

void ff_rtp_send_data(AVFormatContext *s1, const uint8_t *buf1, int len, int m)

{

    RTPMuxContext *s = s1->priv_data;

    dprintf(s1, "rtp_send_data size=%d\n", len);

    /* build the RTP header */

    put_byte(s1->pb, (RTP_VERSION << 6));

    put_byte(s1->pb, (s->payload_type & 0x7f) | ((m & 0x01) << 7));

    put_be16(s1->pb, s->seq);

    put_be32(s1->pb, s->timestamp);

    put_be32(s1->pb, s->ssrc);

    put_buffer(s1->pb, buf1, len);

    put_flush_packet(s1->pb);

    s->seq++;

    s->octet_count += len;

    s->packet_count++;

}

/* send an integer number of samples and compute time stamp and fill

   the rtp send buffer before sending. */

static void rtp_send_samples(AVFormatContext *s1,

                             const uint8_t *buf1, int size, int sample_size)

{

    RTPMuxContext *s = s1->priv_data;

    int len, max_packet_size, n;

    max_packet_size = (s->max_payload_size / sample_size) * sample_size;

    /* not needed, but who nows */

    if ((size % sample_size) != 0)

        av_abort();

    n = 0;

    while (size > 0) {

        s->buf_ptr = s->buf;

        len = FFMIN(max_packet_size, size);

        /* copy data */

        memcpy(s->buf_ptr, buf1, len);

        s->buf_ptr += len;

        buf1 += len;

        size -= len;

        s->timestamp = s->cur_timestamp + n / sample_size;

        ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);

        n += (s->buf_ptr - s->buf);

    }

}

/* NOTE: we suppose that exactly one frame is given as argument here */

/* XXX: test it */

static void rtp_send_mpegaudio(AVFormatContext *s1,

                               const uint8_t *buf1, int size)

{

    RTPMuxContext *s = s1->priv_data;

    int len, count, max_packet_size;

    max_packet_size = s->max_payload_size;

    /* test if we must flush because not enough space */

    len = (s->buf_ptr - s->buf);

    if ((len + size) > max_packet_size) {

        if (len > 4) {

            ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);

            s->buf_ptr = s->buf + 4;

        }

    }

    if (s->buf_ptr == s->buf + 4) {

        s->timestamp = s->cur_timestamp;

    }

    /* add the packet */

    if (size > max_packet_size) {

        /* big packet: fragment */

        count = 0;

        while (size > 0) {

            len = max_packet_size - 4;

            if (len > size)

                len = size;

            /* build fragmented packet */

            s->buf[0] = 0;

            s->buf[1] = 0;

            s->buf[2] = count >> 8;

            s->buf[3] = count;

            memcpy(s->buf + 4, buf1, len);

            ff_rtp_send_data(s1, s->buf, len + 4, 0);

            size -= len;

            buf1 += len;

            count += len;

        }

    } else {

        if (s->buf_ptr == s->buf + 4) {

            /* no fragmentation possible */

            s->buf[0] = 0;

            s->buf[1] = 0;

            s->buf[2] = 0;

            s->buf[3] = 0;

        }

        memcpy(s->buf_ptr, buf1, size);

        s->buf_ptr += size;

    }

}

static void rtp_send_raw(AVFormatContext *s1,

                         const uint8_t *buf1, int size)

{

    RTPMuxContext *s = s1->priv_data;

    int len, max_packet_size;

    max_packet_size = s->max_payload_size;

    while (size > 0) {

        len = max_packet_size;

        if (len > size)

            len = size;

        s->timestamp = s->cur_timestamp;

        ff_rtp_send_data(s1, buf1, len, (len == size));

        buf1 += len;

        size -= len;

    }

}

/* NOTE: size is assumed to be an integer multiple of TS_PACKET_SIZE */

static void rtp_send_mpegts_raw(AVFormatContext *s1,

                                const uint8_t *buf1, int size)

{

    RTPMuxContext *s = s1->priv_data;

    int len, out_len;

    while (size >= TS_PACKET_SIZE) {

        len = s->max_payload_size - (s->buf_ptr - s->buf);

        if (len > size)

            len = size;

        memcpy(s->buf_ptr, buf1, len);

        buf1 += len;

        size -= len;

        s->buf_ptr += len;

        out_len = s->buf_ptr - s->buf;

        if (out_len >= s->max_payload_size) {

            ff_rtp_send_data(s1, s->buf, out_len, 0);

            s->buf_ptr = s->buf;

        }

    }

}

/* write an RTP packet. 'buf1' must contain a single specific frame. */

static int rtp_write_packet(AVFormatContext *s1, AVPacket *pkt)

{

    RTPMuxContext *s = s1->priv_data;

    AVStream *st = s1->streams[0];

    int rtcp_bytes;

    int size= pkt->size;

    uint8_t *buf1= pkt->data;

    dprintf(s1, "%d: write len=%d\n", pkt->stream_index, size);

    rtcp_bytes = ((s->octet_count - s->last_octet_count) * RTCP_TX_RATIO_NUM) /

        RTCP_TX_RATIO_DEN;

    if (s->first_packet || ((rtcp_bytes >= RTCP_SR_SIZE) &&

                           (ntp_time() - s->last_rtcp_ntp_time > 5000000))) {

        rtcp_send_sr(s1, ntp_time());

        s->last_octet_count = s->octet_count;

        s->first_packet = 0;

    }

    s->cur_timestamp = s->base_timestamp + pkt->pts;

    switch(st->codec->codec_id) {

    case CODEC_ID_PCM_MULAW:

    case CODEC_ID_PCM_ALAW:

    case CODEC_ID_PCM_U8:

    case CODEC_ID_PCM_S8:

        rtp_send_samples(s1, buf1, size, 1 * st->codec->channels);

        break;

    case CODEC_ID_PCM_U16BE:

    case CODEC_ID_PCM_U16LE:

    case CODEC_ID_PCM_S16BE:

    case CODEC_ID_PCM_S16LE:

        rtp_send_samples(s1, buf1, size, 2 * st->codec->channels);

        break;

    case CODEC_ID_MP2:

    case CODEC_ID_MP3:

        rtp_send_mpegaudio(s1, buf1, size);

        break;

    case CODEC_ID_MPEG1VIDEO:

    case CODEC_ID_MPEG2VIDEO:

        ff_rtp_send_mpegvideo(s1, buf1, size);

        break;

    case CODEC_ID_AAC:

        ff_rtp_send_aac(s1, buf1, size);

        break;

    case CODEC_ID_AMR_NB:

    case CODEC_ID_AMR_WB:

        ff_rtp_send_amr(s1, buf1, size);

        break;

    case CODEC_ID_MPEG2TS:

        rtp_send_mpegts_raw(s1, buf1, size);

        break;

    case CODEC_ID_H264:

        ff_rtp_send_h264(s1, buf1, size);

        break;

    case CODEC_ID_H263:

    case CODEC_ID_H263P:

        ff_rtp_send_h263(s1, buf1, size);

        break;

    default:

        /* better than nothing : send the codec raw data */

        rtp_send_raw(s1, buf1, size);

        break;

    }

    return 0;

}

static int rtp_write_trailer(AVFormatContext *s1)

{

    RTPMuxContext *s = s1->priv_data;

    av_freep(&s->buf);

    return 0;

}

AVOutputFormat rtp_muxer = {

    "rtp",

    NULL_IF_CONFIG_SMALL("RTP output format"),

    NULL,

    NULL,

    sizeof(RTPMuxContext),

    CODEC_ID_PCM_MULAW,

    CODEC_ID_NONE,

    rtp_write_header,

    rtp_write_packet,

    rtp_write_trailer,

};