FFmpeg: libavformat/swfdec.c Source File

00001 /*
00002  * Flash Compatible Streaming Format demuxer
00003  * Copyright (c) 2000 Fabrice Bellard
00004  * Copyright (c) 2003 Tinic Uro
00005  *
00006  * This file is part of FFmpeg.
00007  *
00008  * FFmpeg is free software; you can redistribute it and/or
00009  * modify it under the terms of the GNU Lesser General Public
00010  * License as published by the Free Software Foundation; either
00011  * version 2.1 of the License, or (at your option) any later version.
00012  *
00013  * FFmpeg is distributed in the hope that it will be useful,
00014  * but WITHOUT ANY WARRANTY; without even the implied warranty of
00015  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00016  * Lesser General Public License for more details.
00017  *
00018  * You should have received a copy of the GNU Lesser General Public
00019  * License along with FFmpeg; if not, write to the Free Software
00020  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
00021  */
00022 
00023 #include "libavutil/intreadwrite.h"
00024 #include "swf.h"
00025 
00026 static int get_swf_tag(ByteIOContext *pb, int *len_ptr)
00027 {
00028     int tag, len;
00029 
00030     if (url_feof(pb))
00031         return -1;
00032 
00033     tag = get_le16(pb);
00034     len = tag & 0x3f;
00035     tag = tag >> 6;
00036     if (len == 0x3f) {
00037         len = get_le32(pb);
00038     }
00039 //    av_log(NULL, AV_LOG_DEBUG, "Tag: %d - Len: %d\n", tag, len);
00040     *len_ptr = len;
00041     return tag;
00042 }
00043 
00044 
00045 static int swf_probe(AVProbeData *p)
00046 {
00047     /* check file header */
00048     if ((p->buf[0] == 'F' || p->buf[0] == 'C') && p->buf[1] == 'W' &&
00049         p->buf[2] == 'S')
00050         return AVPROBE_SCORE_MAX;
00051     else
00052         return 0;
00053 }
00054 
00055 static int swf_read_header(AVFormatContext *s, AVFormatParameters *ap)
00056 {
00057     SWFContext *swf = s->priv_data;
00058     ByteIOContext *pb = s->pb;
00059     int nbits, len, tag;
00060 
00061     tag = get_be32(pb) & 0xffffff00;
00062 
00063     if (tag == MKBETAG('C', 'W', 'S', 0)) {
00064         av_log(s, AV_LOG_ERROR, "Compressed SWF format not supported\n");
00065         return AVERROR(EIO);
00066     }
00067     if (tag != MKBETAG('F', 'W', 'S', 0))
00068         return AVERROR(EIO);
00069     get_le32(pb);
00070     /* skip rectangle size */
00071     nbits = get_byte(pb) >> 3;
00072     len = (4 * nbits - 3 + 7) / 8;
00073     url_fskip(pb, len);
00074     swf->frame_rate = get_le16(pb); /* 8.8 fixed */
00075     get_le16(pb); /* frame count */
00076 
00077     swf->samples_per_frame = 0;
00078     s->ctx_flags |= AVFMTCTX_NOHEADER;
00079     return 0;
00080 }
00081 
00082 static int swf_read_packet(AVFormatContext *s, AVPacket *pkt)
00083 {
00084     SWFContext *swf = s->priv_data;
00085     ByteIOContext *pb = s->pb;
00086     AVStream *vst = NULL, *ast = NULL, *st = 0;
00087     int tag, len, i, frame, v;
00088 
00089     for(;;) {
00090         tag = get_swf_tag(pb, &len);
00091         if (tag < 0)
00092             return AVERROR(EIO);
00093         if (tag == TAG_VIDEOSTREAM && !vst) {
00094             int ch_id = get_le16(pb);
00095             get_le16(pb);
00096             get_le16(pb);
00097             get_le16(pb);
00098             get_byte(pb);
00099             /* Check for FLV1 */
00100             vst = av_new_stream(s, ch_id);
00101             if (!vst)
00102                 return -1;
00103             vst->codec->codec_type = CODEC_TYPE_VIDEO;
00104             vst->codec->codec_id = codec_get_id(swf_codec_tags, get_byte(pb));
00105             av_set_pts_info(vst, 64, 256, swf->frame_rate);
00106             vst->codec->time_base = (AVRational){ 256, swf->frame_rate };
00107             len -= 10;
00108         } else if ((tag == TAG_STREAMHEAD || tag == TAG_STREAMHEAD2) && !ast) {
00109             /* streaming found */
00110             int sample_rate_code;
00111             get_byte(pb);
00112             v = get_byte(pb);
00113             swf->samples_per_frame = get_le16(pb);
00114             ast = av_new_stream(s, -1); /* -1 to avoid clash with video stream ch_id */
00115             if (!ast)
00116                 return -1;
00117             swf->audio_stream_index = ast->index;
00118             ast->codec->channels = 1 + (v&1);
00119             ast->codec->codec_type = CODEC_TYPE_AUDIO;
00120             ast->codec->codec_id = codec_get_id(swf_audio_codec_tags, (v>>4) & 15);
00121             ast->need_parsing = AVSTREAM_PARSE_FULL;
00122             sample_rate_code= (v>>2) & 3;
00123             if (!sample_rate_code)
00124                 return AVERROR(EIO);
00125             ast->codec->sample_rate = 11025 << (sample_rate_code-1);
00126             av_set_pts_info(ast, 64, 1, ast->codec->sample_rate);
00127             len -= 4;
00128         } else if (tag == TAG_VIDEOFRAME) {
00129             int ch_id = get_le16(pb);
00130             len -= 2;
00131             for(i=0; i<s->nb_streams; i++) {
00132                 st = s->streams[i];
00133                 if (st->codec->codec_type == CODEC_TYPE_VIDEO && st->id == ch_id) {
00134                     frame = get_le16(pb);
00135                     av_get_packet(pb, pkt, len-2);
00136                     pkt->pts = frame;
00137                     pkt->stream_index = st->index;
00138                     return pkt->size;
00139                 }
00140             }
00141         } else if (tag == TAG_STREAMBLOCK) {
00142             st = s->streams[swf->audio_stream_index];
00143             if (st->codec->codec_id == CODEC_ID_MP3) {
00144                 url_fskip(pb, 4);
00145                 av_get_packet(pb, pkt, len-4);
00146             } else { // ADPCM, PCM
00147                 av_get_packet(pb, pkt, len);
00148             }
00149             pkt->stream_index = st->index;
00150             return pkt->size;
00151         } else if (tag == TAG_JPEG2) {
00152             for (i=0; i<s->nb_streams; i++) {
00153                 st = s->streams[i];
00154                 if (st->id == -2)
00155                     break;
00156             }
00157             if (i == s->nb_streams) {
00158                 vst = av_new_stream(s, -2); /* -2 to avoid clash with video stream and audio stream */
00159                 if (!vst)
00160                     return -1;
00161                 vst->codec->codec_type = CODEC_TYPE_VIDEO;
00162                 vst->codec->codec_id = CODEC_ID_MJPEG;
00163                 av_set_pts_info(vst, 64, 256, swf->frame_rate);
00164                 vst->codec->time_base = (AVRational){ 256, swf->frame_rate };
00165                 st = vst;
00166             }
00167             get_le16(pb); /* BITMAP_ID */
00168             av_new_packet(pkt, len-2);
00169             get_buffer(pb, pkt->data, 4);
00170             if (AV_RB32(pkt->data) == 0xffd8ffd9 ||
00171                 AV_RB32(pkt->data) == 0xffd9ffd8) {
00172                 /* old SWF files containing SOI/EOI as data start */
00173                 /* files created by swink have reversed tag */
00174                 pkt->size -= 4;
00175                 get_buffer(pb, pkt->data, pkt->size);
00176             } else {
00177                 get_buffer(pb, pkt->data + 4, pkt->size - 4);
00178             }
00179             pkt->stream_index = st->index;
00180             return pkt->size;
00181         }
00182         url_fskip(pb, len);
00183     }
00184     return 0;
00185 }
00186 
00187 AVInputFormat swf_demuxer = {
00188     "swf",
00189     NULL_IF_CONFIG_SMALL("Flash format"),
00190     sizeof(SWFContext),
00191     swf_probe,
00192     swf_read_header,
00193     swf_read_packet,
00194 };