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ffmpeg / libavformat / oggenc.c @ 2dd3c9e0

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/*
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 * Ogg muxer
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 * Copyright (c) 2007 Baptiste Coudurier <baptiste dot coudurier at free dot fr>
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 *
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 * This file is part of FFmpeg.
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 *
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 * FFmpeg is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
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 * version 2.1 of the License, or (at your option) any later version.
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 *
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 * FFmpeg is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with FFmpeg; if not, write to the Free Software
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 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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 */
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#include "avformat.h"
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#include "crc.h"
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#include "xiph.h"
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#include "bytestream.h"
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typedef struct {
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    int64_t duration;
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    unsigned page_counter;
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    uint8_t *header[3];
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    int header_len[3];
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    /** for theora granule */
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    int kfgshift;
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    int64_t last_kf_pts;
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    int vrev;
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} OGGStreamContext;
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static void ogg_update_checksum(AVFormatContext *s, offset_t crc_offset)
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{
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    offset_t pos = url_ftell(s->pb);
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    uint32_t checksum = get_checksum(s->pb);
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    url_fseek(s->pb, crc_offset, SEEK_SET);
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    put_be32(s->pb, checksum);
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    url_fseek(s->pb, pos, SEEK_SET);
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}
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static int ogg_write_page(AVFormatContext *s, const uint8_t *data, int size,
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                          int64_t granule, int stream_index, int flags)
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{
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    OGGStreamContext *oggstream = s->streams[stream_index]->priv_data;
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    offset_t crc_offset;
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    int page_segments, i;
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    if (size >= 255*255) {
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        granule = -1;
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        size = 255*255;
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    }
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    page_segments = FFMIN((size/255)+!!size, 255);
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    init_checksum(s->pb, ff_crc04C11DB7_update, 0);
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    put_tag(s->pb, "OggS");
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    put_byte(s->pb, 0);
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    put_byte(s->pb, flags);
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    put_le64(s->pb, granule);
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    put_le32(s->pb, stream_index);
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    put_le32(s->pb, oggstream->page_counter++);
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    crc_offset = url_ftell(s->pb);
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    put_le32(s->pb, 0); // crc
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    put_byte(s->pb, page_segments);
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    for (i = 0; i < page_segments-1; i++)
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        put_byte(s->pb, 255);
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    if (size) {
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        put_byte(s->pb, size - (page_segments-1)*255);
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        put_buffer(s->pb, data, size);
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    }
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    ogg_update_checksum(s, crc_offset);
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    put_flush_packet(s->pb);
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    return size;
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}
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static int ogg_build_flac_headers(const uint8_t *extradata, int extradata_size,
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                                  OGGStreamContext *oggstream, int bitexact)
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{
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    const char *vendor = bitexact ? "ffmpeg" : LIBAVFORMAT_IDENT;
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    uint8_t *p;
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    if (extradata_size != 34)
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        return -1;
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    oggstream->header_len[0] = 79;
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    oggstream->header[0] = av_mallocz(79); // per ogg flac specs
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    p = oggstream->header[0];
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    bytestream_put_byte(&p, 0x7F);
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    bytestream_put_buffer(&p, "FLAC", 4);
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    bytestream_put_byte(&p, 1); // major version
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    bytestream_put_byte(&p, 0); // minor version
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    bytestream_put_be16(&p, 1); // headers packets without this one
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    bytestream_put_buffer(&p, "fLaC", 4);
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    bytestream_put_byte(&p, 0x00); // streaminfo
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    bytestream_put_be24(&p, 34);
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    bytestream_put_buffer(&p, extradata, 34);
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    oggstream->header_len[1] = 1+3+4+strlen(vendor)+4;
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    oggstream->header[1] = av_mallocz(oggstream->header_len[1]);
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    p = oggstream->header[1];
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    bytestream_put_byte(&p, 0x84); // last metadata block and vorbis comment
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    bytestream_put_be24(&p, oggstream->header_len[1] - 4);
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    bytestream_put_le32(&p, strlen(vendor));
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    bytestream_put_buffer(&p, vendor, strlen(vendor));
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    bytestream_put_le32(&p, 0); // user comment list length
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    return 0;
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}
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static int ogg_write_header(AVFormatContext *s)
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{
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    OGGStreamContext *oggstream;
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    int i, j;
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    for (i = 0; i < s->nb_streams; i++) {
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        AVStream *st = s->streams[i];
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        if (st->codec->codec_type == CODEC_TYPE_AUDIO)
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            av_set_pts_info(st, 64, 1, st->codec->sample_rate);
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        else if (st->codec->codec_type == CODEC_TYPE_VIDEO)
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            av_set_pts_info(st, 64, st->codec->time_base.num, st->codec->time_base.den);
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        if (st->codec->codec_id != CODEC_ID_VORBIS &&
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            st->codec->codec_id != CODEC_ID_THEORA &&
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            st->codec->codec_id != CODEC_ID_FLAC) {
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            av_log(s, AV_LOG_ERROR, "Unsupported codec id in stream %d\n", i);
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            return -1;
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        }
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        if (!st->codec->extradata || !st->codec->extradata_size) {
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            av_log(s, AV_LOG_ERROR, "No extradata present\n");
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            return -1;
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        }
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        oggstream = av_mallocz(sizeof(*oggstream));
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        st->priv_data = oggstream;
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        if (st->codec->codec_id == CODEC_ID_FLAC) {
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            if (ogg_build_flac_headers(st->codec->extradata, st->codec->extradata_size,
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                                       oggstream, st->codec->flags & CODEC_FLAG_BITEXACT) < 0) {
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                av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
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                av_freep(&st->priv_data);
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            }
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        } else {
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            if (ff_split_xiph_headers(st->codec->extradata, st->codec->extradata_size,
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                                      st->codec->codec_id == CODEC_ID_VORBIS ? 30 : 42,
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                                      oggstream->header, oggstream->header_len) < 0) {
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                av_log(s, AV_LOG_ERROR, "Extradata corrupted\n");
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                av_freep(&st->priv_data);
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                return -1;
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            }
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            if (st->codec->codec_id == CODEC_ID_THEORA) {
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                /** KFGSHIFT is the width of the less significant section of the granule position
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                    The less significant section is the frame count since the last keyframe */
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                oggstream->kfgshift = ((oggstream->header[0][40]&3)<<3)|(oggstream->header[0][41]>>5);
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                oggstream->vrev = oggstream->header[0][9];
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                av_log(s, AV_LOG_DEBUG, "theora kfgshift %d, vrev %d\n",
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                       oggstream->kfgshift, oggstream->vrev);
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            }
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        }
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    }
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    for (i = 0; i < 3; i++) {
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        for (j = 0; j < s->nb_streams; j++) {
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            AVStream *st = s->streams[j];
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            OGGStreamContext *oggstream = st->priv_data;
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            if (oggstream && oggstream->header_len[i]) {
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                ogg_write_page(s, oggstream->header[i], oggstream->header_len[i],
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                               0, st->index, i ? 0 : 2); // bos
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            }
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        }
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    }
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    return 0;
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}
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static int ogg_write_packet(AVFormatContext *s, AVPacket *pkt)
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{
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    AVStream *st = s->streams[pkt->stream_index];
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    OGGStreamContext *oggstream = st->priv_data;
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    uint8_t *ptr = pkt->data;
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    int ret, size = pkt->size;
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    int64_t granule;
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    if (st->codec->codec_id == CODEC_ID_THEORA) {
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        int64_t pts = oggstream->vrev < 1 ? pkt->pts : pkt->pts + pkt->duration;
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        int pframe_count;
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        if (pkt->flags & PKT_FLAG_KEY)
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            oggstream->last_kf_pts = pts;
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        pframe_count = pts - oggstream->last_kf_pts;
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        // prevent frame count from overflow if key frame flag is not set
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        if (pframe_count >= (1<<oggstream->kfgshift)) {
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            oggstream->last_kf_pts += pframe_count;
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            pframe_count = 0;
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        }
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        granule = (oggstream->last_kf_pts<<oggstream->kfgshift) | pframe_count;
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    } else
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        granule = pkt->pts + pkt->duration;
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    oggstream->duration = granule;
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    do {
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        ret = ogg_write_page(s, ptr, size, granule, pkt->stream_index, ptr != pkt->data);
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        ptr  += ret; size -= ret;
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    } while (size > 0 || ret == 255*255); // need to output a last nil page
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    return 0;
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}
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static int ogg_write_trailer(AVFormatContext *s)
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{
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    int i;
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    for (i = 0; i < s->nb_streams; i++) {
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        AVStream *st = s->streams[i];
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        OGGStreamContext *oggstream = st->priv_data;
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        ogg_write_page(s, NULL, 0, oggstream->duration, i, 4); // eos
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        if (st->codec->codec_id == CODEC_ID_FLAC) {
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            av_free(oggstream->header[0]);
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            av_free(oggstream->header[1]);
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        }
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        av_freep(&st->priv_data);
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    }
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    return 0;
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}
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AVOutputFormat ogg_muxer = {
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    "ogg",
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    "Ogg format",
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    "application/ogg",
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    "ogg",
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    0,
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    CODEC_ID_FLAC,
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    CODEC_ID_THEORA,
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    ogg_write_header,
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    ogg_write_packet,
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    ogg_write_trailer,
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};