PeerStreamer

/*

 * FFM (ffserver live feed) demuxer

 * Copyright (c) 2001 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 "libavutil/intreadwrite.h"

#include "avformat.h"

#include "ffm.h"

#if CONFIG_FFSERVER

#include <unistd.h>

int64_t ffm_read_write_index(int fd)

{

    uint8_t buf[8];

    lseek(fd, 8, SEEK_SET);

    if (read(fd, buf, 8) != 8)

        return AVERROR(EIO);

    return AV_RB64(buf);

}

int ffm_write_write_index(int fd, int64_t pos)

{

    uint8_t buf[8];

    int i;

    for(i=0;i<8;i++)

        buf[i] = (pos >> (56 - i * 8)) & 0xff;

    lseek(fd, 8, SEEK_SET);

    if (write(fd, buf, 8) != 8)

        return AVERROR(EIO);

    return 8;

}

void ffm_set_write_index(AVFormatContext *s, int64_t pos, int64_t file_size)

{

    FFMContext *ffm = s->priv_data;

    ffm->write_index = pos;

    ffm->file_size = file_size;

}

#endif // CONFIG_FFSERVER

static int ffm_is_avail_data(AVFormatContext *s, int size)

{

    FFMContext *ffm = s->priv_data;

    int64_t pos, avail_size;

    int len;

    len = ffm->packet_end - ffm->packet_ptr;

    if (size <= len)

        return 1;

    pos = url_ftell(s->pb);

    if (!ffm->write_index) {

        if (pos == ffm->file_size)

            return AVERROR_EOF;

        avail_size = ffm->file_size - pos;

    } else {

    if (pos == ffm->write_index) {

        /* exactly at the end of stream */

        return AVERROR(EAGAIN);

    } else if (pos < ffm->write_index) {

        avail_size = ffm->write_index - pos;

    } else {

        avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);

    }

    }

    avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;

    if (size <= avail_size)

        return 1;

    else

        return AVERROR(EAGAIN);

}

static int ffm_resync(AVFormatContext *s, int state)

{

    av_log(s, AV_LOG_ERROR, "resyncing\n");

    while (state != PACKET_ID) {

        if (url_feof(s->pb)) {

            av_log(s, AV_LOG_ERROR, "cannot find FFM syncword\n");

            return -1;

        }

        state = (state << 8) | get_byte(s->pb);

    }

    return 0;

}

/* first is true if we read the frame header */

static int ffm_read_data(AVFormatContext *s,

                         uint8_t *buf, int size, int header)

{

    FFMContext *ffm = s->priv_data;

    ByteIOContext *pb = s->pb;

    int len, fill_size, size1, frame_offset, id;

    size1 = size;

    while (size > 0) {

    redo:

        len = ffm->packet_end - ffm->packet_ptr;

        if (len < 0)

            return -1;

        if (len > size)

            len = size;

        if (len == 0) {

            if (url_ftell(pb) == ffm->file_size)

                url_fseek(pb, ffm->packet_size, SEEK_SET);

    retry_read:

            id = get_be16(pb); /* PACKET_ID */

            if (id != PACKET_ID)

                if (ffm_resync(s, id) < 0)

                    return -1;

            fill_size = get_be16(pb);

            ffm->dts = get_be64(pb);

            frame_offset = get_be16(pb);

            get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);

            ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);

            if (ffm->packet_end < ffm->packet || frame_offset < 0)

                return -1;

            /* if first packet or resynchronization packet, we must

               handle it specifically */

            if (ffm->first_packet || (frame_offset & 0x8000)) {

                if (!frame_offset) {

                    /* This packet has no frame headers in it */

                    if (url_ftell(pb) >= ffm->packet_size * 3) {

                        url_fseek(pb, -ffm->packet_size * 2, SEEK_CUR);

                        goto retry_read;

                    }

                    /* This is bad, we cannot find a valid frame header */

                    return 0;

                }

                ffm->first_packet = 0;

                if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)

                    return -1;

                ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;

                if (!header)

                    break;

            } else {

                ffm->packet_ptr = ffm->packet;

            }

            goto redo;

        }

        memcpy(buf, ffm->packet_ptr, len);

        buf += len;

        ffm->packet_ptr += len;

        size -= len;

        header = 0;

    }

    return size1 - size;

}

//#define DEBUG_SEEK

/* ensure that acutal seeking happens between FFM_PACKET_SIZE

   and file_size - FFM_PACKET_SIZE */

static void ffm_seek1(AVFormatContext *s, int64_t pos1)

{

    FFMContext *ffm = s->priv_data;

    ByteIOContext *pb = s->pb;

    int64_t pos;

    pos = FFMIN(pos1, ffm->file_size - FFM_PACKET_SIZE);

    pos = FFMAX(pos, FFM_PACKET_SIZE);

#ifdef DEBUG_SEEK

    av_log(s, AV_LOG_DEBUG, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);

#endif

    url_fseek(pb, pos, SEEK_SET);

}

static int64_t get_dts(AVFormatContext *s, int64_t pos)

{

    ByteIOContext *pb = s->pb;

    int64_t dts;

    ffm_seek1(s, pos);

    url_fskip(pb, 4);

    dts = get_be64(pb);

#ifdef DEBUG_SEEK

    av_log(s, AV_LOG_DEBUG, "dts=%0.6f\n", dts / 1000000.0);

#endif

    return dts;

}

static void adjust_write_index(AVFormatContext *s)

{

    FFMContext *ffm = s->priv_data;

    ByteIOContext *pb = s->pb;

    int64_t pts;

    //int64_t orig_write_index = ffm->write_index;

    int64_t pos_min, pos_max;

    int64_t pts_start;

    int64_t ptr = url_ftell(pb);

    pos_min = 0;

    pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;

    pts_start = get_dts(s, pos_min);

    pts = get_dts(s, pos_max);

    if (pts - 100000 > pts_start)

        goto end;

    ffm->write_index = FFM_PACKET_SIZE;

    pts_start = get_dts(s, pos_min);

    pts = get_dts(s, pos_max);

    if (pts - 100000 <= pts_start) {

        while (1) {

            int64_t newpos;

            int64_t newpts;

            newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;

            if (newpos == pos_min)

                break;

            newpts = get_dts(s, newpos);

            if (newpts - 100000 <= pts) {

                pos_max = newpos;

                pts = newpts;

            } else {

                pos_min = newpos;

            }

        }

        ffm->write_index += pos_max;

    }

    //printf("Adjusted write index from %"PRId64" to %"PRId64": pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);

    //printf("pts range %0.6f - %0.6f\n", get_dts(s, 0) / 1000000. , get_dts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. );

 end:

    url_fseek(pb, ptr, SEEK_SET);

}

static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)

{

    FFMContext *ffm = s->priv_data;

    AVStream *st;

    ByteIOContext *pb = s->pb;

    AVCodecContext *codec;

    int i, nb_streams;

    uint32_t tag;

    /* header */

    tag = get_le32(pb);

    if (tag != MKTAG('F', 'F', 'M', '1'))

        goto fail;

    ffm->packet_size = get_be32(pb);

    if (ffm->packet_size != FFM_PACKET_SIZE)

        goto fail;

    ffm->write_index = get_be64(pb);

    /* get also filesize */

    if (!url_is_streamed(pb)) {

        ffm->file_size = url_fsize(pb);

        if (ffm->write_index)

            adjust_write_index(s);

    } else {

        ffm->file_size = (UINT64_C(1) << 63) - 1;

    }

    nb_streams = get_be32(pb);

    get_be32(pb); /* total bitrate */

    /* read each stream */

    for(i=0;i<nb_streams;i++) {

        char rc_eq_buf[128];

        st = av_new_stream(s, 0);

        if (!st)

            goto fail;

        av_set_pts_info(st, 64, 1, 1000000);

        codec = st->codec;

        /* generic info */

        codec->codec_id = get_be32(pb);

        codec->codec_type = get_byte(pb); /* codec_type */

        codec->bit_rate = get_be32(pb);

        st->quality = get_be32(pb);

        codec->flags = get_be32(pb);

        codec->flags2 = get_be32(pb);

        codec->debug = get_be32(pb);

        /* specific info */

        switch(codec->codec_type) {

        case CODEC_TYPE_VIDEO:

            codec->time_base.num = get_be32(pb);

            codec->time_base.den = get_be32(pb);

            codec->width = get_be16(pb);

            codec->height = get_be16(pb);

            codec->gop_size = get_be16(pb);

            codec->pix_fmt = get_be32(pb);

            codec->qmin = get_byte(pb);

            codec->qmax = get_byte(pb);

            codec->max_qdiff = get_byte(pb);

            codec->qcompress = get_be16(pb) / 10000.0;

            codec->qblur = get_be16(pb) / 10000.0;

            codec->bit_rate_tolerance = get_be32(pb);

            codec->rc_eq = av_strdup(get_strz(pb, rc_eq_buf, sizeof(rc_eq_buf)));

            codec->rc_max_rate = get_be32(pb);

            codec->rc_min_rate = get_be32(pb);

            codec->rc_buffer_size = get_be32(pb);

            codec->i_quant_factor = av_int2dbl(get_be64(pb));

            codec->b_quant_factor = av_int2dbl(get_be64(pb));

            codec->i_quant_offset = av_int2dbl(get_be64(pb));

            codec->b_quant_offset = av_int2dbl(get_be64(pb));

            codec->dct_algo = get_be32(pb);

            codec->strict_std_compliance = get_be32(pb);

            codec->max_b_frames = get_be32(pb);

            codec->luma_elim_threshold = get_be32(pb);

            codec->chroma_elim_threshold = get_be32(pb);

            codec->mpeg_quant = get_be32(pb);

            codec->intra_dc_precision = get_be32(pb);

            codec->me_method = get_be32(pb);

            codec->mb_decision = get_be32(pb);

            codec->nsse_weight = get_be32(pb);

            codec->frame_skip_cmp = get_be32(pb);

            codec->rc_buffer_aggressivity = av_int2dbl(get_be64(pb));

            codec->codec_tag = get_be32(pb);

            codec->thread_count = get_byte(pb);

            codec->coder_type = get_be32(pb);

            codec->me_cmp = get_be32(pb);

            codec->partitions = get_be32(pb);

            codec->me_subpel_quality = get_be32(pb);

            codec->me_range = get_be32(pb);

            codec->keyint_min = get_be32(pb);

            codec->scenechange_threshold = get_be32(pb);

            codec->b_frame_strategy = get_be32(pb);

            codec->qcompress = av_int2dbl(get_be64(pb));

            codec->qblur = av_int2dbl(get_be64(pb));

            codec->max_qdiff = get_be32(pb);

            codec->refs = get_be32(pb);

            codec->directpred = get_be32(pb);

            break;

        case CODEC_TYPE_AUDIO:

            codec->sample_rate = get_be32(pb);

            codec->channels = get_le16(pb);

            codec->frame_size = get_le16(pb);

            codec->sample_fmt = get_le16(pb);

            break;

        default:

            goto fail;

        }

        if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {

            codec->extradata_size = get_be32(pb);

            codec->extradata = av_malloc(codec->extradata_size);

            if (!codec->extradata)

                return AVERROR(ENOMEM);

            get_buffer(pb, codec->extradata, codec->extradata_size);

        }

    }

    /* get until end of block reached */

    while ((url_ftell(pb) % ffm->packet_size) != 0)

        get_byte(pb);

    /* init packet demux */

    ffm->packet_ptr = ffm->packet;

    ffm->packet_end = ffm->packet;

    ffm->frame_offset = 0;

    ffm->dts = 0;

    ffm->read_state = READ_HEADER;

    ffm->first_packet = 1;

    return 0;

 fail:

    for(i=0;i<s->nb_streams;i++) {

        st = s->streams[i];

        if (st) {

            av_free(st);

        }

    }

    return -1;

}

/* return < 0 if eof */

static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)

{

    int size;

    FFMContext *ffm = s->priv_data;

    int duration, ret;

    switch(ffm->read_state) {

    case READ_HEADER:

        if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)

            return ret;

        dprintf(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",

               url_ftell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);

        if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=

            FRAME_HEADER_SIZE)

            return -1;

        if (ffm->header[1] & FLAG_DTS)

            if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)

                return -1;

#if 0

        av_hexdump_log(s, AV_LOG_DEBUG, ffm->header, FRAME_HEADER_SIZE);

#endif

        ffm->read_state = READ_DATA;

        /* fall thru */

    case READ_DATA:

        size = AV_RB24(ffm->header + 2);

        if ((ret = ffm_is_avail_data(s, size)) < 0)

            return ret;

        duration = AV_RB24(ffm->header + 5);

        av_new_packet(pkt, size);

        pkt->stream_index = ffm->header[0];

        if ((unsigned)pkt->stream_index >= s->nb_streams) {

            av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);

            av_free_packet(pkt);

            ffm->read_state = READ_HEADER;

            return -1;

        }

        pkt->pos = url_ftell(s->pb);

        if (ffm->header[1] & FLAG_KEY_FRAME)

            pkt->flags |= PKT_FLAG_KEY;

        ffm->read_state = READ_HEADER;

        if (ffm_read_data(s, pkt->data, size, 0) != size) {

            /* bad case: desynchronized packet. we cancel all the packet loading */

            av_free_packet(pkt);

            return -1;

        }

        pkt->pts = AV_RB64(ffm->header+8);

        if (ffm->header[1] & FLAG_DTS)

            pkt->dts = pkt->pts - AV_RB32(ffm->header+16);

        else

            pkt->dts = pkt->pts;

        pkt->duration = duration;

        break;

    }

    return 0;

}

/* seek to a given time in the file. The file read pointer is

   positioned at or before pts. XXX: the following code is quite

   approximative */

static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)

{

    FFMContext *ffm = s->priv_data;

    int64_t pos_min, pos_max, pos;

    int64_t pts_min, pts_max, pts;

    double pos1;

#ifdef DEBUG_SEEK

    av_log(s, AV_LOG_DEBUG, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);

#endif

    /* find the position using linear interpolation (better than

       dichotomy in typical cases) */

    pos_min = FFM_PACKET_SIZE;

    pos_max = ffm->file_size - FFM_PACKET_SIZE;

    while (pos_min <= pos_max) {

        pts_min = get_dts(s, pos_min);

        pts_max = get_dts(s, pos_max);

        /* linear interpolation */

        pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /

            (double)(pts_max - pts_min);

        pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;

        if (pos <= pos_min)

            pos = pos_min;

        else if (pos >= pos_max)

            pos = pos_max;

        pts = get_dts(s, pos);

        /* check if we are lucky */

        if (pts == wanted_pts) {

            goto found;

        } else if (pts > wanted_pts) {

            pos_max = pos - FFM_PACKET_SIZE;

        } else {

            pos_min = pos + FFM_PACKET_SIZE;

        }

    }

    pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;

 found:

    ffm_seek1(s, pos);

    /* reset read state */

    ffm->read_state = READ_HEADER;

    ffm->packet_ptr = ffm->packet;

    ffm->packet_end = ffm->packet;

    ffm->first_packet = 1;

    return 0;

}

static int ffm_probe(AVProbeData *p)

{

    if (

        p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&

        p->buf[3] == '1')

        return AVPROBE_SCORE_MAX + 1;

    return 0;

}

AVInputFormat ffm_demuxer = {

    "ffm",

    NULL_IF_CONFIG_SMALL("FFM (FFserver live feed) format"),

    sizeof(FFMContext),

    ffm_probe,

    ffm_read_header,

    ffm_read_packet,

    NULL,

    ffm_seek,

};