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/libavformat/vocdec.c

http://github.com/FFmpeg/FFmpeg
C | 110 lines | 75 code | 14 blank | 21 comment | 13 complexity | 259d6ca96cdb11e7ac4d4a0da8f990f3 MD5 | raw file
  1/*
  2 * Creative Voice File demuxer.
  3 * Copyright (c) 2006  Aurelien Jacobs <aurel@gnuage.org>
  4 *
  5 * This file is part of FFmpeg.
  6 *
  7 * FFmpeg is free software; you can redistribute it and/or
  8 * modify it under the terms of the GNU Lesser General Public
  9 * License as published by the Free Software Foundation; either
 10 * version 2.1 of the License, or (at your option) any later version.
 11 *
 12 * FFmpeg is distributed in the hope that it will be useful,
 13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 15 * Lesser General Public License for more details.
 16 *
 17 * You should have received a copy of the GNU Lesser General Public
 18 * License along with FFmpeg; if not, write to the Free Software
 19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 20 */
 21
 22#include "libavutil/intreadwrite.h"
 23#include "voc.h"
 24#include "internal.h"
 25
 26static int voc_probe(const AVProbeData *p)
 27{
 28    int version, check;
 29
 30    if (memcmp(p->buf, ff_voc_magic, sizeof(ff_voc_magic) - 1))
 31        return 0;
 32    version = AV_RL16(p->buf + 22);
 33    check = AV_RL16(p->buf + 24);
 34    if (~version + 0x1234 != check)
 35        return 10;
 36
 37    return AVPROBE_SCORE_MAX;
 38}
 39
 40static int voc_read_header(AVFormatContext *s)
 41{
 42    VocDecContext *voc = s->priv_data;
 43    AVIOContext *pb = s->pb;
 44    int header_size;
 45
 46    avio_skip(pb, 20);
 47    header_size = avio_rl16(pb) - 22;
 48    if (header_size != 4) {
 49        av_log(s, AV_LOG_ERROR, "unknown header size: %d\n", header_size);
 50        return AVERROR(ENOSYS);
 51    }
 52    avio_skip(pb, header_size);
 53
 54    s->ctx_flags |= AVFMTCTX_NOHEADER;
 55
 56    voc->remaining_size = 0;
 57    return 0;
 58}
 59
 60static int voc_read_packet(AVFormatContext *s, AVPacket *pkt)
 61{
 62    if (!s->nb_streams) {
 63        AVStream *st = avformat_new_stream(s, NULL);
 64        if (!st)
 65            return AVERROR(ENOMEM);
 66        st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
 67    }
 68    return ff_voc_get_packet(s, pkt, s->streams[0], 0);
 69}
 70
 71static int voc_read_seek(AVFormatContext *s, int stream_index,
 72                         int64_t timestamp, int flags)
 73{
 74    VocDecContext *voc = s->priv_data;
 75    AVStream *st;
 76    int index;
 77
 78    if (s->nb_streams < 1) {
 79        av_log(s, AV_LOG_ERROR, "cannot seek while no stream was found yet\n");
 80        return AVERROR(EINVAL);
 81    }
 82
 83    st = s->streams[stream_index];
 84    index = av_index_search_timestamp(st, timestamp, flags);
 85
 86    if (index >= 0 && index < st->nb_index_entries - 1) {
 87        AVIndexEntry *e = &st->index_entries[index];
 88        avio_seek(s->pb, e->pos, SEEK_SET);
 89        voc->pts = e->timestamp;
 90        voc->remaining_size = e->size;
 91        return 0;
 92    } else if (st->nb_index_entries && st->index_entries[0].timestamp <= timestamp) {
 93        AVIndexEntry *e = &st->index_entries[st->nb_index_entries - 1];
 94        // prepare context for seek_frame_generic()
 95        voc->pts = e->timestamp;
 96        voc->remaining_size = e->size;
 97    }
 98    return -1;
 99}
100
101AVInputFormat ff_voc_demuxer = {
102    .name           = "voc",
103    .long_name      = NULL_IF_CONFIG_SMALL("Creative Voice"),
104    .priv_data_size = sizeof(VocDecContext),
105    .read_probe     = voc_probe,
106    .read_header    = voc_read_header,
107    .read_packet    = voc_read_packet,
108    .read_seek      = voc_read_seek,
109    .codec_tag      = (const AVCodecTag* const []){ ff_voc_codec_tags, 0 },
110};