format_kate.c 4.88 KB
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/* Icecast
 *
 * This program is distributed under the GNU General Public License, version 2.
 * A copy of this license is included with this source.
 *
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 * Copyright 2000-2004, Jack Moffitt <jack@xiph.org,
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 *                      Michael Smith <msmith@xiph.org>,
 *                      oddsock <oddsock@xiph.org>,
 *                      Karl Heyes <karl@xiph.org>
 *                      and others (see AUTHORS for details).
 */


/* Ogg codec handler for kate logical streams */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdlib.h>
#include <string.h>
#include <ogg/ogg.h>

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#include "compat.h"
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#include "refbuf.h"
#include "format_ogg.h"
#include "format_kate.h"
#include "client.h"
#include "stats.h"

#define CATMODULE "format-kate"
#include "logging.h"


typedef struct _kate_codec_tag
{
    int             headers_done;
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    size_t          num_headers;
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    ogg_int64_t     last_iframe;
    ogg_int64_t     prev_granulepos;
} kate_codec_t;


static void kate_codec_free (ogg_state_t *ogg_info, ogg_codec_t *codec)
{
    kate_codec_t *kate = codec->specific;

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    ICECAST_LOG_DEBUG("freeing kate codec");
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    /* TODO: should i replace with something or just remove
    stats_event (ogg_info->mount, "video_bitrate", NULL);
    stats_event (ogg_info->mount, "video_quality", NULL);
    stats_event (ogg_info->mount, "frame_rate", NULL);
    stats_event (ogg_info->mount, "frame_size", NULL);
    */
    ogg_stream_clear (&codec->os);
    free (kate);
    free (codec);
}


/* kate pages are not rebuilt, so here we just for headers and then
 * pass them straight through to the the queue
 */
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static refbuf_t *process_kate_page (ogg_state_t *ogg_info, ogg_codec_t *codec, ogg_page *page, format_plugin_t *plugin)
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{
    kate_codec_t *kate = codec->specific;
    ogg_packet packet;
    int header_page = 0;
    refbuf_t *refbuf = NULL;
    ogg_int64_t granulepos;

    if (ogg_stream_pagein (&codec->os, page) < 0)
    {
        ogg_info->error = 1;
        return NULL;
    }
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    granulepos = ogg_page_granulepos(page);
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    while (ogg_stream_packetout (&codec->os, &packet) > 0)
    {
        if (!kate->headers_done)
        {
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            header_page = (packet.bytes > 0 && (packet.packet[0] & 0x80));
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            if (!header_page)
                break;
            codec->headers++;
            if (packet.packet[0]==0x80)
            {
                if (packet.bytes<64) return NULL;
                /* we peek for the number of headers to expect */
                kate->num_headers = packet.packet[11];
            }
            continue;
        }

        if (codec->headers < kate->num_headers)
        {
            ogg_info->error = 1;
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            ICECAST_LOG_ERROR("Not enough header packets");
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            return NULL;
        }
    }
    if (header_page)
    {
        format_ogg_attach_header (ogg_info, page);
        return NULL;
    }

    refbuf = make_refbuf_with_page (page);
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    /* ICECAST_LOG_DEBUG("refbuf %p has pageno %ld, %llu", refbuf, ogg_page_pageno (page), (uint64_t)granulepos); */
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    if (codec->possible_start)
    {
        /* we don't bother trying to know where we can start, we'll just
           start whenever we have to, video's more important and in the majority
           of the cases it's ok if we lose an event we're seeking in the middle
           of, as we won't have display artifacts as we'd have with video */
        codec->possible_start->sync_point = 1;
        refbuf_release (codec->possible_start);
        codec->possible_start = NULL;
    }
    if (granulepos != kate->prev_granulepos || granulepos == 0)
    {
        if (codec->possible_start)
            refbuf_release (codec->possible_start);
        refbuf_addref (refbuf);
        codec->possible_start = refbuf;
    }
    kate->prev_granulepos = granulepos;

    return refbuf;
}


/* Check if specified BOS page is the start of a kate stream and
 * if so, create a codec structure for handling it
 */
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ogg_codec_t *initial_kate_page(format_plugin_t *plugin, ogg_page *page)
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{
    ogg_state_t *ogg_info = plugin->_state;
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    ogg_codec_t *codec = calloc(1, sizeof(ogg_codec_t));
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    ogg_packet packet;

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    kate_codec_t *kate_codec = calloc(1, sizeof(kate_codec_t));
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    ogg_stream_init(&codec->os, ogg_page_serialno(page));
    ogg_stream_pagein(&codec->os, page);
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    ogg_stream_packetout(&codec->os, &packet);
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    ICECAST_LOG_DEBUG("checking for kate codec");
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    /* we don't have libkate, so we examine the packet magic by hand */
    if ((packet.bytes<9) || memcmp(packet.packet, "\x80kate\0\0\0\0", 9))
    {
        ogg_stream_clear (&codec->os);
        free (kate_codec);
        free (codec);
        return NULL;
    }

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    ICECAST_LOG_INFO("seen initial kate header");
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    codec->specific = kate_codec;
    codec->process_page = process_kate_page;
    codec->codec_free = kate_codec_free;
    codec->headers = 1;
    codec->name = "Kate";

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    format_ogg_attach_header(ogg_info, page);
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    ogg_info->codec_sync = codec;
    return codec;
}