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libavformat/filmstripdec.c

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00001 /*
00002  * Adobe Filmstrip demuxer
00003  * Copyright (c) 2010 Peter Ross
00004  *
00005  * This file is part of FFmpeg.
00006  *
00007  * FFmpeg is free software; you can redistribute it and/or
00008  * modify it under the terms of the GNU Lesser General Public
00009  * License as published by the Free Software Foundation; either
00010  * version 2.1 of the License, or (at your option) any later version.
00011  *
00012  * FFmpeg is distributed in the hope that it will be useful,
00013  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00014  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00015  * Lesser General Public License for more details.
00016  *
00017  * You should have received a copy of the GNU Lesser General Public
00018  * License along with FFmpeg; if not, write to the Free Software
00019  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00020  */
00021 
00027 #include "libavutil/intreadwrite.h"
00028 #include "avformat.h"
00029 
00030 #define RAND_TAG MKBETAG('R','a','n','d')
00031 
00032 typedef struct {
00033     int leading;
00034 } FilmstripDemuxContext;
00035 
00036 static int read_header(AVFormatContext *s,
00037                        AVFormatParameters *ap)
00038 {
00039     FilmstripDemuxContext *film = s->priv_data;
00040     ByteIOContext *pb = s->pb;
00041     AVStream *st;
00042 
00043     if (url_is_streamed(s->pb))
00044         return AVERROR(EIO);
00045 
00046     url_fseek(pb, url_fsize(pb) - 36, SEEK_SET);
00047     if (get_be32(pb) != RAND_TAG) {
00048         av_log(s, AV_LOG_ERROR, "magic number not found");
00049         return AVERROR_INVALIDDATA;
00050     }
00051 
00052     st = av_new_stream(s, 0);
00053     if (!st)
00054         return AVERROR(ENOMEM);
00055 
00056     st->nb_frames = get_be32(pb);
00057     if (get_be16(pb) != 0) {
00058         av_log_ask_for_sample(s, "unsupported packing method\n");
00059         return AVERROR_INVALIDDATA;
00060     }
00061 
00062     url_fskip(pb, 2);
00063     st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
00064     st->codec->codec_id   = CODEC_ID_RAWVIDEO;
00065     st->codec->pix_fmt    = PIX_FMT_RGBA;
00066     st->codec->codec_tag  = 0; /* no fourcc */
00067     st->codec->width      = get_be16(pb);
00068     st->codec->height     = get_be16(pb);
00069     film->leading         = get_be16(pb);
00070     av_set_pts_info(st, 64, 1, get_be16(pb));
00071 
00072     url_fseek(pb, 0, SEEK_SET);
00073 
00074     return 0;
00075 }
00076 
00077 static int read_packet(AVFormatContext *s,
00078                        AVPacket *pkt)
00079 {
00080     FilmstripDemuxContext *film = s->priv_data;
00081     AVStream *st = s->streams[0];
00082 
00083     if (url_feof(s->pb))
00084         return AVERROR(EIO);
00085     pkt->dts = url_ftell(s->pb) / (st->codec->width * (st->codec->height + film->leading) * 4);
00086     pkt->size = av_get_packet(s->pb, pkt, st->codec->width * st->codec->height * 4);
00087     url_fskip(s->pb, st->codec->width * film->leading * 4);
00088     if (pkt->size < 0)
00089         return pkt->size;
00090     pkt->flags |= AV_PKT_FLAG_KEY;
00091     return 0;
00092 }
00093 
00094 static int read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
00095 {
00096     AVStream *st = s->streams[stream_index];
00097     url_fseek(s->pb, FFMAX(timestamp, 0) * st->codec->width * st->codec->height * 4, SEEK_SET);
00098     return 0;
00099 }
00100 
00101 AVInputFormat filmstrip_demuxer = {
00102     "filmstrip",
00103     NULL_IF_CONFIG_SMALL("Adobe Filmstrip"),
00104     sizeof(FilmstripDemuxContext),
00105     NULL,
00106     read_header,
00107     read_packet,
00108     NULL,
00109     read_seek,
00110     .extensions = "flm",
00111 };

Generated on Fri Sep 16 2011 17:17:48 for FFmpeg by  doxygen 1.7.1