PeerStreamer

/*

 * Ogg muxer

 * Copyright (c) 2007 Baptiste Coudurier <baptiste dot coudurier at free dot fr>

 *

 * 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/crc.h"

#include "libavcodec/xiph.h"

#include "libavcodec/bytestream.h"

#include "libavcodec/flac.h"

#include "avformat.h"

#include "internal.h"

typedef struct {

    int64_t duration;

    unsigned page_counter;

    uint8_t *header[3];

    int header_len[3];

    /** for theora granule */

    int kfgshift;

    int64_t last_kf_pts;

    int vrev;

    int eos;

    unsigned packet_count; ///< number of packet buffered

} OGGStreamContext;

static void ogg_update_checksum(AVFormatContext *s, int64_t crc_offset)

{

    int64_t pos = url_ftell(s->pb);

    uint32_t checksum = get_checksum(s->pb);

    url_fseek(s->pb, crc_offset, SEEK_SET);

    put_be32(s->pb, checksum);

    url_fseek(s->pb, pos, SEEK_SET);

}

static int ogg_write_page(AVFormatContext *s, const uint8_t *data, int size,

                          int64_t granule, int stream_index, int flags)

{

    OGGStreamContext *oggstream = s->streams[stream_index]->priv_data;

    int64_t crc_offset;

    int page_segments, i;

    if (size >= 255*255) {

        granule = -1;

        size = 255*255;

    } else if (oggstream->eos)

        flags |= 4;

    page_segments = FFMIN(size/255 + 1, 255);

    init_checksum(s->pb, ff_crc04C11DB7_update, 0);

    put_tag(s->pb, "OggS");

    put_byte(s->pb, 0);

    put_byte(s->pb, flags);

    put_le64(s->pb, granule);

    put_le32(s->pb, stream_index);

    put_le32(s->pb, oggstream->page_counter++);

    crc_offset = url_ftell(s->pb);

    put_le32(s->pb, 0); // crc

    put_byte(s->pb, page_segments);

    for (i = 0; i < page_segments-1; i++)

        put_byte(s->pb, 255);

    put_byte(s->pb, size - (page_segments-1)*255);

    put_buffer(s->pb, data, size);

    ogg_update_checksum(s, crc_offset);

    put_flush_packet(s->pb);

    return size;

}

static uint8_t *ogg_write_vorbiscomment(int offset, int bitexact,

                                        int *header_len)

{

    const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;

    int size;

    uint8_t *p, *p0;

    size = offset + 4 + strlen(vendor) + 4;

    p = av_mallocz(size);

    if (!p)

        return NULL;

    p0 = p;

    p += offset;

    bytestream_put_le32(&p, strlen(vendor));

    bytestream_put_buffer(&p, vendor, strlen(vendor));

    bytestream_put_le32(&p, 0); // user comment list length

    *header_len = size;

    return p0;

}

static int ogg_build_flac_headers(AVCodecContext *avctx,

                                  OGGStreamContext *oggstream, int bitexact)

{

    enum FLACExtradataFormat format;

    uint8_t *streaminfo;

    uint8_t *p;

    if (!ff_flac_is_extradata_valid(avctx, &format, &streaminfo))

        return -1;

    // first packet: STREAMINFO

    oggstream->header_len[0] = 51;

    oggstream->header[0] = av_mallocz(51); // per ogg flac specs

    p = oggstream->header[0];

    if (!p)

        return AVERROR_NOMEM;

    bytestream_put_byte(&p, 0x7F);

    bytestream_put_buffer(&p, "FLAC", 4);

    bytestream_put_byte(&p, 1); // major version

    bytestream_put_byte(&p, 0); // minor version

    bytestream_put_be16(&p, 1); // headers packets without this one

    bytestream_put_buffer(&p, "fLaC", 4);

    bytestream_put_byte(&p, 0x00); // streaminfo

    bytestream_put_be24(&p, 34);

    bytestream_put_buffer(&p, streaminfo, FLAC_STREAMINFO_SIZE);

    // second packet: VorbisComment

    p = ogg_write_vorbiscomment(4, bitexact, &oggstream->header_len[1]);

    if (!p)

        return AVERROR_NOMEM;

    oggstream->header[1] = p;

    bytestream_put_byte(&p, 0x84); // last metadata block and vorbis comment

    bytestream_put_be24(&p, oggstream->header_len[1] - 4);

    return 0;

}

#define SPEEX_HEADER_SIZE 80

static int ogg_build_speex_headers(AVCodecContext *avctx,

                                   OGGStreamContext *oggstream, int bitexact)

{

    uint8_t *p;

    if (avctx->extradata_size < SPEEX_HEADER_SIZE)

        return -1;

    // first packet: Speex header

    p = av_mallocz(SPEEX_HEADER_SIZE);

    if (!p)

        return AVERROR_NOMEM;

    oggstream->header[0] = p;

    oggstream->header_len[0] = SPEEX_HEADER_SIZE;

    bytestream_put_buffer(&p, avctx->extradata, SPEEX_HEADER_SIZE);

    AV_WL32(&oggstream->header[0][68], 0);  // set extra_headers to 0

    // second packet: VorbisComment

    p = ogg_write_vorbiscomment(0, bitexact, &oggstream->header_len[1]);

    if (!p)

        return AVERROR_NOMEM;

    oggstream->header[1] = p;

    return 0;

}

static int ogg_write_header(AVFormatContext *s)

{

    OGGStreamContext *oggstream;

    int i, j;

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

        AVStream *st = s->streams[i];

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

            av_set_pts_info(st, 64, 1, st->codec->sample_rate);

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

            av_set_pts_info(st, 64, st->codec->time_base.num, st->codec->time_base.den);

        if (st->codec->codec_id != CODEC_ID_VORBIS &&

            st->codec->codec_id != CODEC_ID_THEORA &&

            st->codec->codec_id != CODEC_ID_SPEEX  &&

            st->codec->codec_id != CODEC_ID_FLAC) {

            av_log(s, AV_LOG_ERROR, "Unsupported codec id in stream %d\n", i);

            return -1;

        }

        if (!st->codec->extradata || !st->codec->extradata_size) {

            av_log(s, AV_LOG_ERROR, "No extradata present\n");

            return -1;

        }

        oggstream = av_mallocz(sizeof(*oggstream));

        st->priv_data = oggstream;

        if (st->codec->codec_id == CODEC_ID_FLAC) {

            int err = ogg_build_flac_headers(st->codec, oggstream,

                                             st->codec->flags & CODEC_FLAG_BITEXACT);

            if (err) {

                av_log(s, AV_LOG_ERROR, "Error writing FLAC headers\n");

                av_freep(&st->priv_data);

                return err;

            }

        } else if (st->codec->codec_id == CODEC_ID_SPEEX) {

            int err = ogg_build_speex_headers(st->codec, oggstream,

                                              st->codec->flags & CODEC_FLAG_BITEXACT);

            if (err) {

                av_log(s, AV_LOG_ERROR, "Error writing Speex headers\n");

                av_freep(&st->priv_data);

                return err;

            }

        } else {

            if (ff_split_xiph_headers(st->codec->extradata, st->codec->extradata_size,

                                      st->codec->codec_id == CODEC_ID_VORBIS ? 30 : 42,

                                      oggstream->header, oggstream->header_len) < 0) {

                av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");

                av_freep(&st->priv_data);

                return -1;

            }

            if (st->codec->codec_id == CODEC_ID_THEORA) {

                /** KFGSHIFT is the width of the less significant section of the granule position

                    The less significant section is the frame count since the last keyframe */

                oggstream->kfgshift = ((oggstream->header[0][40]&3)<<3)|(oggstream->header[0][41]>>5);

                oggstream->vrev = oggstream->header[0][9];

                av_log(s, AV_LOG_DEBUG, "theora kfgshift %d, vrev %d\n",

                       oggstream->kfgshift, oggstream->vrev);

            }

        }

    }

    for (i = 0; i < 3; i++) {

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

            AVStream *st = s->streams[j];

            OGGStreamContext *oggstream = st->priv_data;

            if (oggstream && oggstream->header_len[i]) {

                ogg_write_page(s, oggstream->header[i], oggstream->header_len[i],

                               0, st->index, i ? 0 : 2); // bos

            }

        }

    }

    return 0;

}

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

{

    AVStream *st = s->streams[pkt->stream_index];

    OGGStreamContext *oggstream = st->priv_data;

    uint8_t *ptr = pkt->data;

    int ret, size = pkt->size;

    int64_t granule;

    if (st->codec->codec_id == CODEC_ID_THEORA) {

        int64_t pts = oggstream->vrev < 1 ? pkt->pts : pkt->pts + pkt->duration;

        int pframe_count;

        if (pkt->flags & PKT_FLAG_KEY)

            oggstream->last_kf_pts = pts;

        pframe_count = pts - oggstream->last_kf_pts;

        // prevent frame count from overflow if key frame flag is not set

        if (pframe_count >= (1<<oggstream->kfgshift)) {

            oggstream->last_kf_pts += pframe_count;

            pframe_count = 0;

        }

        granule = (oggstream->last_kf_pts<<oggstream->kfgshift) | pframe_count;

    } else

        granule = pkt->pts + pkt->duration;

    oggstream->duration = granule;

    do {

        ret = ogg_write_page(s, ptr, size, granule, pkt->stream_index, ptr != pkt->data);

        ptr  += ret; size -= ret;

    } while (size > 0 || ret == 255*255); // need to output a last nil page

    return 0;

}

static int ogg_compare_granule(AVFormatContext *s, AVPacket *next, AVPacket *pkt)

{

    AVStream *st2 = s->streams[next->stream_index];

    AVStream *st  = s->streams[pkt ->stream_index];

    int64_t next_granule = av_rescale_q(next->pts + next->duration,

                                        st2->time_base, AV_TIME_BASE_Q);

    int64_t cur_granule  = av_rescale_q(pkt ->pts + pkt ->duration,

                                        st ->time_base, AV_TIME_BASE_Q);

    return next_granule > cur_granule;

}

static int ogg_interleave_per_granule(AVFormatContext *s, AVPacket *out, AVPacket *pkt, int flush)

{

    OGGStreamContext *ogg;

    int i, stream_count = 0;

    int interleaved = 0;

    if (pkt) {

        ff_interleave_add_packet(s, pkt, ogg_compare_granule);

        ogg = s->streams[pkt->stream_index]->priv_data;

        ogg->packet_count++;

    }

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

        ogg = s->streams[i]->priv_data;

        stream_count += !!ogg->packet_count;

        interleaved += ogg->packet_count > 1;

    }

    if ((s->nb_streams == stream_count && interleaved == stream_count) ||

        (flush && stream_count)) {

        AVPacketList *pktl= s->packet_buffer;

        *out= pktl->pkt;

        s->packet_buffer = pktl->next;

        ogg = s->streams[out->stream_index]->priv_data;

        if (flush && ogg->packet_count == 1)

            ogg->eos = 1;

        ogg->packet_count--;

        if(!s->packet_buffer)

            s->packet_buffer_end= NULL;

        if(s->streams[out->stream_index]->last_in_packet_buffer == pktl)

            s->streams[out->stream_index]->last_in_packet_buffer= NULL;

        av_freep(&pktl);

        return 1;

    } else {

        av_init_packet(out);

        return 0;

    }

}

static int ogg_write_trailer(AVFormatContext *s)

{

    int i;

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

        AVStream *st = s->streams[i];

        OGGStreamContext *oggstream = st->priv_data;

        if (st->codec->codec_id == CODEC_ID_FLAC ||

            st->codec->codec_id == CODEC_ID_SPEEX) {

            av_free(oggstream->header[0]);

            av_free(oggstream->header[1]);

        }

        av_freep(&st->priv_data);

    }

    return 0;

}

AVOutputFormat ogg_muxer = {

    "ogg",

    NULL_IF_CONFIG_SMALL("Ogg"),

    "application/ogg",

    "ogg,ogv,spx",

    0,

    CODEC_ID_FLAC,

    CODEC_ID_THEORA,

    ogg_write_header,

    ogg_write_packet,

    ogg_write_trailer,

    .interleave_packet = ogg_interleave_per_granule,

};