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"

#include "vorbiscomment.h"

#define MAX_PAGE_SIZE 65025

typedef struct {

    int64_t granule;

    int stream_index;

    uint8_t flags;

    uint8_t segments_count;

    uint8_t segments[255];

    uint8_t data[MAX_PAGE_SIZE];

    uint16_t size;

} OGGPage;

typedef struct {

    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 page_count; ///< number of page buffered

    OGGPage page; ///< current page

} OGGStreamContext;

typedef struct OGGPageList {

    OGGPage page;

    struct OGGPageList *next;

} OGGPageList;

typedef struct {

    OGGPageList *page_list;

} OGGContext;

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 void ogg_write_page(AVFormatContext *s, OGGPage *page, int extra_flags)

{

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

    int64_t crc_offset;

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

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

    put_byte(s->pb, 0);

    put_byte(s->pb, page->flags | extra_flags);

    put_le64(s->pb, page->granule);

    put_le32(s->pb, page->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_count);

    put_buffer(s->pb, page->segments, page->segments_count);

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

    ogg_update_checksum(s, crc_offset);

    put_flush_packet(s->pb);

    oggstream->page_count--;

}

static int64_t ogg_granule_to_timestamp(OGGStreamContext *oggstream, OGGPage *page)

{

    if (oggstream->kfgshift)

        return (page->granule>>oggstream->kfgshift) +

            (page->granule & ((1<<oggstream->kfgshift)-1));

    else

        return page->granule;

}

static int ogg_compare_granule(AVFormatContext *s, OGGPage *next, OGGPage *page)

{

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

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

    int64_t next_granule, cur_granule;

    if (next->granule == -1 || page->granule == -1)

        return 0;

    next_granule = av_rescale_q(ogg_granule_to_timestamp(st2->priv_data, next),

                                st2->time_base, AV_TIME_BASE_Q);

    cur_granule  = av_rescale_q(ogg_granule_to_timestamp(st->priv_data, page),

                                st ->time_base, AV_TIME_BASE_Q);

    return next_granule > cur_granule;

}

static int ogg_reset_cur_page(OGGStreamContext *oggstream)

{

    oggstream->page.granule = -1;

    oggstream->page.flags = 0;

    oggstream->page.segments_count = 0;

    oggstream->page.size = 0;

    return 0;

}

static int ogg_buffer_page(AVFormatContext *s, OGGStreamContext *oggstream)

{

    OGGContext *ogg = s->priv_data;

    OGGPageList **p = &ogg->page_list;

    OGGPageList *l = av_mallocz(sizeof(*l));

    if (!l)

        return AVERROR(ENOMEM);

    l->page = oggstream->page;

    oggstream->page_count++;

    ogg_reset_cur_page(oggstream);

    while (*p) {

        if (ogg_compare_granule(s, &(*p)->page, &l->page))

            break;

        p = &(*p)->next;

    }

    l->next = *p;

    *p = l;

    return 0;

}

static int ogg_buffer_data(AVFormatContext *s, AVStream *st,

                           uint8_t *data, unsigned size, int64_t granule)

{

    OGGStreamContext *oggstream = st->priv_data;

    int total_segments = size / 255 + 1;

    uint8_t *p = data;

    int i, segments, len;

    for (i = 0; i < total_segments; ) {

        OGGPage *page = &oggstream->page;

        segments = FFMIN(total_segments - i, 255 - page->segments_count);

        if (i && !page->segments_count)

            page->flags |= 1; // continued packet

        memset(page->segments+page->segments_count, 255, segments - 1);

        page->segments_count += segments - 1;

        len = FFMIN(size, segments*255);

        page->segments[page->segments_count++] = len - (segments-1)*255;

        memcpy(page->data+page->size, p, len);

        p += len;

        size -= len;

        i += segments;

        page->size += len;

        if (i == total_segments)

            page->granule = granule;

        if (page->segments_count == 255) {

            ogg_buffer_page(s, oggstream);

        }

    }

    return 0;

}

static uint8_t *ogg_write_vorbiscomment(int offset, int bitexact,

                                        int *header_len, AVMetadata *m)

{

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

    int size;

    uint8_t *p, *p0;

    unsigned int count;

    size = offset + ff_vorbiscomment_length(m, vendor, &count);

    p = av_mallocz(size);

    if (!p)

        return NULL;

    p0 = p;

    p += offset;

    ff_vorbiscomment_write(&p, m, vendor, count);

    *header_len = size;

    return p0;

}

static int ogg_build_flac_headers(AVCodecContext *avctx,

                                  OGGStreamContext *oggstream, int bitexact,

                                  AVMetadata *m)

{

    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(ENOMEM);

    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], m);

    if (!p)

        return AVERROR(ENOMEM);

    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,

                                   AVMetadata *m)

{

    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(ENOMEM);

    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], m);

    if (!p)

        return AVERROR(ENOMEM);

    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 == AVMEDIA_TYPE_AUDIO)

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

        else if (st->codec->codec_type == AVMEDIA_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));

        oggstream->page.stream_index = i;

        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,

                                             s->metadata);

            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,

                                              s->metadata);

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

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

        ogg_buffer_data(s, s->streams[j], oggstream->header[0],

                        oggstream->header_len[0], 0);

        oggstream->page.flags |= 2; // bos

        ogg_buffer_page(s, oggstream);

    }

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

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

        OGGStreamContext *oggstream = st->priv_data;

        for (i = 1; i < 3; i++) {

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

                ogg_buffer_data(s, st, oggstream->header[i],

                                oggstream->header_len[i], 0);

        }

        ogg_buffer_page(s, oggstream);

    }

    return 0;

}

static void ogg_write_pages(AVFormatContext *s, int flush)

{

    OGGContext *ogg = s->priv_data;

    OGGPageList *next, *p;

    if (!ogg->page_list)

        return;

    for (p = ogg->page_list; p; ) {

        OGGStreamContext *oggstream =

            s->streams[p->page.stream_index]->priv_data;

        if (oggstream->page_count < 2 && !flush)

            break;

        ogg_write_page(s, &p->page,

                       flush && oggstream->page_count == 1 ? 4 : 0); // eos

        next = p->next;

        av_freep(&p);

        p = next;

    }

    ogg->page_list = p;

}

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

{

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

    OGGStreamContext *oggstream = st->priv_data;

    int ret;

    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 & AV_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;

    ret = ogg_buffer_data(s, st, pkt->data, pkt->size, granule);

    if (ret < 0)

        return ret;

    ogg_write_pages(s, 0);

    return 0;

}

static int ogg_write_trailer(AVFormatContext *s)

{

    int i;

    /* flush current page */

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

        ogg_buffer_page(s, s->streams[i]->priv_data);

    ogg_write_pages(s, 1);

    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",

    sizeof(OGGContext),

    CODEC_ID_FLAC,

    CODEC_ID_THEORA,

    ogg_write_header,

    ogg_write_packet,

    ogg_write_trailer,

    .metadata_conv = ff_vorbiscomment_metadata_conv,

};