FFmpeg: libavformat/ffmdec.c Source File

00001 /*
00002  * FFM (ffserver live feed) demuxer
00003  * Copyright (c) 2001 Fabrice Bellard
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 
00022 #include "libavutil/intreadwrite.h"
00023 #include "avformat.h"
00024 #include "ffm.h"
00025 #if CONFIG_FFSERVER
00026 #include <unistd.h>
00027 
00028 int64_t ffm_read_write_index(int fd)
00029 {
00030     uint8_t buf[8];
00031 
00032     lseek(fd, 8, SEEK_SET);
00033     if (read(fd, buf, 8) != 8)
00034         return AVERROR(EIO);
00035     return AV_RB64(buf);
00036 }
00037 
00038 int ffm_write_write_index(int fd, int64_t pos)
00039 {
00040     uint8_t buf[8];
00041     int i;
00042 
00043     for(i=0;i<8;i++)
00044         buf[i] = (pos >> (56 - i * 8)) & 0xff;
00045     lseek(fd, 8, SEEK_SET);
00046     if (write(fd, buf, 8) != 8)
00047         return AVERROR(EIO);
00048     return 8;
00049 }
00050 
00051 void ffm_set_write_index(AVFormatContext *s, int64_t pos, int64_t file_size)
00052 {
00053     FFMContext *ffm = s->priv_data;
00054     ffm->write_index = pos;
00055     ffm->file_size = file_size;
00056 }
00057 #endif // CONFIG_FFSERVER
00058 
00059 static int ffm_is_avail_data(AVFormatContext *s, int size)
00060 {
00061     FFMContext *ffm = s->priv_data;
00062     int64_t pos, avail_size;
00063     int len;
00064 
00065     len = ffm->packet_end - ffm->packet_ptr;
00066     if (size <= len)
00067         return 1;
00068     pos = url_ftell(s->pb);
00069     if (!ffm->write_index) {
00070         if (pos == ffm->file_size)
00071             return AVERROR_EOF;
00072         avail_size = ffm->file_size - pos;
00073     } else {
00074     if (pos == ffm->write_index) {
00075         /* exactly at the end of stream */
00076         return AVERROR(EAGAIN);
00077     } else if (pos < ffm->write_index) {
00078         avail_size = ffm->write_index - pos;
00079     } else {
00080         avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);
00081     }
00082     }
00083     avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;
00084     if (size <= avail_size)
00085         return 1;
00086     else
00087         return AVERROR(EAGAIN);
00088 }
00089 
00090 static int ffm_resync(AVFormatContext *s, int state)
00091 {
00092     av_log(s, AV_LOG_ERROR, "resyncing\n");
00093     while (state != PACKET_ID) {
00094         if (url_feof(s->pb)) {
00095             av_log(s, AV_LOG_ERROR, "cannot find FFM syncword\n");
00096             return -1;
00097         }
00098         state = (state << 8) | get_byte(s->pb);
00099     }
00100     return 0;
00101 }
00102 
00103 /* first is true if we read the frame header */
00104 static int ffm_read_data(AVFormatContext *s,
00105                          uint8_t *buf, int size, int header)
00106 {
00107     FFMContext *ffm = s->priv_data;
00108     ByteIOContext *pb = s->pb;
00109     int len, fill_size, size1, frame_offset, id;
00110 
00111     size1 = size;
00112     while (size > 0) {
00113     redo:
00114         len = ffm->packet_end - ffm->packet_ptr;
00115         if (len < 0)
00116             return -1;
00117         if (len > size)
00118             len = size;
00119         if (len == 0) {
00120             if (url_ftell(pb) == ffm->file_size)
00121                 url_fseek(pb, ffm->packet_size, SEEK_SET);
00122     retry_read:
00123             id = get_be16(pb); /* PACKET_ID */
00124             if (id != PACKET_ID)
00125                 if (ffm_resync(s, id) < 0)
00126                     return -1;
00127             fill_size = get_be16(pb);
00128             ffm->dts = get_be64(pb);
00129             frame_offset = get_be16(pb);
00130             get_buffer(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);
00131             ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);
00132             if (ffm->packet_end < ffm->packet || frame_offset < 0)
00133                 return -1;
00134             /* if first packet or resynchronization packet, we must
00135                handle it specifically */
00136             if (ffm->first_packet || (frame_offset & 0x8000)) {
00137                 if (!frame_offset) {
00138                     /* This packet has no frame headers in it */
00139                     if (url_ftell(pb) >= ffm->packet_size * 3) {
00140                         url_fseek(pb, -ffm->packet_size * 2, SEEK_CUR);
00141                         goto retry_read;
00142                     }
00143                     /* This is bad, we cannot find a valid frame header */
00144                     return 0;
00145                 }
00146                 ffm->first_packet = 0;
00147                 if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)
00148                     return -1;
00149                 ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;
00150                 if (!header)
00151                     break;
00152             } else {
00153                 ffm->packet_ptr = ffm->packet;
00154             }
00155             goto redo;
00156         }
00157         memcpy(buf, ffm->packet_ptr, len);
00158         buf += len;
00159         ffm->packet_ptr += len;
00160         size -= len;
00161         header = 0;
00162     }
00163     return size1 - size;
00164 }
00165 
00166 //#define DEBUG_SEEK
00167 
00168 /* ensure that acutal seeking happens between FFM_PACKET_SIZE
00169    and file_size - FFM_PACKET_SIZE */
00170 static void ffm_seek1(AVFormatContext *s, int64_t pos1)
00171 {
00172     FFMContext *ffm = s->priv_data;
00173     ByteIOContext *pb = s->pb;
00174     int64_t pos;
00175 
00176     pos = FFMIN(pos1, ffm->file_size - FFM_PACKET_SIZE);
00177     pos = FFMAX(pos, FFM_PACKET_SIZE);
00178 #ifdef DEBUG_SEEK
00179     av_log(s, AV_LOG_DEBUG, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);
00180 #endif
00181     url_fseek(pb, pos, SEEK_SET);
00182 }
00183 
00184 static int64_t get_dts(AVFormatContext *s, int64_t pos)
00185 {
00186     ByteIOContext *pb = s->pb;
00187     int64_t dts;
00188 
00189     ffm_seek1(s, pos);
00190     url_fskip(pb, 4);
00191     dts = get_be64(pb);
00192 #ifdef DEBUG_SEEK
00193     av_log(s, AV_LOG_DEBUG, "dts=%0.6f\n", dts / 1000000.0);
00194 #endif
00195     return dts;
00196 }
00197 
00198 static void adjust_write_index(AVFormatContext *s)
00199 {
00200     FFMContext *ffm = s->priv_data;
00201     ByteIOContext *pb = s->pb;
00202     int64_t pts;
00203     //int64_t orig_write_index = ffm->write_index;
00204     int64_t pos_min, pos_max;
00205     int64_t pts_start;
00206     int64_t ptr = url_ftell(pb);
00207 
00208 
00209     pos_min = 0;
00210     pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;
00211 
00212     pts_start = get_dts(s, pos_min);
00213 
00214     pts = get_dts(s, pos_max);
00215 
00216     if (pts - 100000 > pts_start)
00217         goto end;
00218 
00219     ffm->write_index = FFM_PACKET_SIZE;
00220 
00221     pts_start = get_dts(s, pos_min);
00222 
00223     pts = get_dts(s, pos_max);
00224 
00225     if (pts - 100000 <= pts_start) {
00226         while (1) {
00227             int64_t newpos;
00228             int64_t newpts;
00229 
00230             newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;
00231 
00232             if (newpos == pos_min)
00233                 break;
00234 
00235             newpts = get_dts(s, newpos);
00236 
00237             if (newpts - 100000 <= pts) {
00238                 pos_max = newpos;
00239                 pts = newpts;
00240             } else {
00241                 pos_min = newpos;
00242             }
00243         }
00244         ffm->write_index += pos_max;
00245     }
00246 
00247     //printf("Adjusted write index from %"PRId64" to %"PRId64": pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);
00248     //printf("pts range %0.6f - %0.6f\n", get_dts(s, 0) / 1000000. , get_dts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. );
00249 
00250  end:
00251     url_fseek(pb, ptr, SEEK_SET);
00252 }
00253 
00254 
00255 static int ffm_close(AVFormatContext *s)
00256 {
00257     int i;
00258 
00259     for (i = 0; i < s->nb_streams; i++)
00260         av_freep(&s->streams[i]->codec->rc_eq);
00261 
00262     return 0;
00263 }
00264 
00265 
00266 static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)
00267 {
00268     FFMContext *ffm = s->priv_data;
00269     AVStream *st;
00270     ByteIOContext *pb = s->pb;
00271     AVCodecContext *codec;
00272     int i, nb_streams;
00273     uint32_t tag;
00274 
00275     /* header */
00276     tag = get_le32(pb);
00277     if (tag != MKTAG('F', 'F', 'M', '1'))
00278         goto fail;
00279     ffm->packet_size = get_be32(pb);
00280     if (ffm->packet_size != FFM_PACKET_SIZE)
00281         goto fail;
00282     ffm->write_index = get_be64(pb);
00283     /* get also filesize */
00284     if (!url_is_streamed(pb)) {
00285         ffm->file_size = url_fsize(pb);
00286         if (ffm->write_index)
00287             adjust_write_index(s);
00288     } else {
00289         ffm->file_size = (UINT64_C(1) << 63) - 1;
00290     }
00291 
00292     nb_streams = get_be32(pb);
00293     get_be32(pb); /* total bitrate */
00294     /* read each stream */
00295     for(i=0;i<nb_streams;i++) {
00296         char rc_eq_buf[128];
00297 
00298         st = av_new_stream(s, 0);
00299         if (!st)
00300             goto fail;
00301 
00302         av_set_pts_info(st, 64, 1, 1000000);
00303 
00304         codec = st->codec;
00305         /* generic info */
00306         codec->codec_id = get_be32(pb);
00307         codec->codec_type = get_byte(pb); /* codec_type */
00308         codec->bit_rate = get_be32(pb);
00309         st->quality = get_be32(pb);
00310         codec->flags = get_be32(pb);
00311         codec->flags2 = get_be32(pb);
00312         codec->debug = get_be32(pb);
00313         /* specific info */
00314         switch(codec->codec_type) {
00315         case AVMEDIA_TYPE_VIDEO:
00316             codec->time_base.num = get_be32(pb);
00317             codec->time_base.den = get_be32(pb);
00318             codec->width = get_be16(pb);
00319             codec->height = get_be16(pb);
00320             codec->gop_size = get_be16(pb);
00321             codec->pix_fmt = get_be32(pb);
00322             codec->qmin = get_byte(pb);
00323             codec->qmax = get_byte(pb);
00324             codec->max_qdiff = get_byte(pb);
00325             codec->qcompress = get_be16(pb) / 10000.0;
00326             codec->qblur = get_be16(pb) / 10000.0;
00327             codec->bit_rate_tolerance = get_be32(pb);
00328             codec->rc_eq = av_strdup(get_strz(pb, rc_eq_buf, sizeof(rc_eq_buf)));
00329             codec->rc_max_rate = get_be32(pb);
00330             codec->rc_min_rate = get_be32(pb);
00331             codec->rc_buffer_size = get_be32(pb);
00332             codec->i_quant_factor = av_int2dbl(get_be64(pb));
00333             codec->b_quant_factor = av_int2dbl(get_be64(pb));
00334             codec->i_quant_offset = av_int2dbl(get_be64(pb));
00335             codec->b_quant_offset = av_int2dbl(get_be64(pb));
00336             codec->dct_algo = get_be32(pb);
00337             codec->strict_std_compliance = get_be32(pb);
00338             codec->max_b_frames = get_be32(pb);
00339             codec->luma_elim_threshold = get_be32(pb);
00340             codec->chroma_elim_threshold = get_be32(pb);
00341             codec->mpeg_quant = get_be32(pb);
00342             codec->intra_dc_precision = get_be32(pb);
00343             codec->me_method = get_be32(pb);
00344             codec->mb_decision = get_be32(pb);
00345             codec->nsse_weight = get_be32(pb);
00346             codec->frame_skip_cmp = get_be32(pb);
00347             codec->rc_buffer_aggressivity = av_int2dbl(get_be64(pb));
00348             codec->codec_tag = get_be32(pb);
00349             codec->thread_count = get_byte(pb);
00350             codec->coder_type = get_be32(pb);
00351             codec->me_cmp = get_be32(pb);
00352             codec->partitions = get_be32(pb);
00353             codec->me_subpel_quality = get_be32(pb);
00354             codec->me_range = get_be32(pb);
00355             codec->keyint_min = get_be32(pb);
00356             codec->scenechange_threshold = get_be32(pb);
00357             codec->b_frame_strategy = get_be32(pb);
00358             codec->qcompress = av_int2dbl(get_be64(pb));
00359             codec->qblur = av_int2dbl(get_be64(pb));
00360             codec->max_qdiff = get_be32(pb);
00361             codec->refs = get_be32(pb);
00362             codec->directpred = get_be32(pb);
00363             break;
00364         case AVMEDIA_TYPE_AUDIO:
00365             codec->sample_rate = get_be32(pb);
00366             codec->channels = get_le16(pb);
00367             codec->frame_size = get_le16(pb);
00368             codec->sample_fmt = (int16_t) get_le16(pb);
00369             break;
00370         default:
00371             goto fail;
00372         }
00373         if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {
00374             codec->extradata_size = get_be32(pb);
00375             codec->extradata = av_malloc(codec->extradata_size);
00376             if (!codec->extradata)
00377                 return AVERROR(ENOMEM);
00378             get_buffer(pb, codec->extradata, codec->extradata_size);
00379         }
00380     }
00381 
00382     /* get until end of block reached */
00383     while ((url_ftell(pb) % ffm->packet_size) != 0)
00384         get_byte(pb);
00385 
00386     /* init packet demux */
00387     ffm->packet_ptr = ffm->packet;
00388     ffm->packet_end = ffm->packet;
00389     ffm->frame_offset = 0;
00390     ffm->dts = 0;
00391     ffm->read_state = READ_HEADER;
00392     ffm->first_packet = 1;
00393     return 0;
00394  fail:
00395     ffm_close(s);
00396     return -1;
00397 }
00398 
00399 /* return < 0 if eof */
00400 static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)
00401 {
00402     int size;
00403     FFMContext *ffm = s->priv_data;
00404     int duration, ret;
00405 
00406     switch(ffm->read_state) {
00407     case READ_HEADER:
00408         if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)
00409             return ret;
00410 
00411         dprintf(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",
00412                url_ftell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);
00413         if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=
00414             FRAME_HEADER_SIZE)
00415             return -1;
00416         if (ffm->header[1] & FLAG_DTS)
00417             if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)
00418                 return -1;
00419 #if 0
00420         av_hexdump_log(s, AV_LOG_DEBUG, ffm->header, FRAME_HEADER_SIZE);
00421 #endif
00422         ffm->read_state = READ_DATA;
00423         /* fall thru */
00424     case READ_DATA:
00425         size = AV_RB24(ffm->header + 2);
00426         if ((ret = ffm_is_avail_data(s, size)) < 0)
00427             return ret;
00428 
00429         duration = AV_RB24(ffm->header + 5);
00430 
00431         av_new_packet(pkt, size);
00432         pkt->stream_index = ffm->header[0];
00433         if ((unsigned)pkt->stream_index >= s->nb_streams) {
00434             av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);
00435             av_free_packet(pkt);
00436             ffm->read_state = READ_HEADER;
00437             return -1;
00438         }
00439         pkt->pos = url_ftell(s->pb);
00440         if (ffm->header[1] & FLAG_KEY_FRAME)
00441             pkt->flags |= AV_PKT_FLAG_KEY;
00442 
00443         ffm->read_state = READ_HEADER;
00444         if (ffm_read_data(s, pkt->data, size, 0) != size) {
00445             /* bad case: desynchronized packet. we cancel all the packet loading */
00446             av_free_packet(pkt);
00447             return -1;
00448         }
00449         pkt->pts = AV_RB64(ffm->header+8);
00450         if (ffm->header[1] & FLAG_DTS)
00451             pkt->dts = pkt->pts - AV_RB32(ffm->header+16);
00452         else
00453             pkt->dts = pkt->pts;
00454         pkt->duration = duration;
00455         break;
00456     }
00457     return 0;
00458 }
00459 
00460 /* seek to a given time in the file. The file read pointer is
00461    positioned at or before pts. XXX: the following code is quite
00462    approximative */
00463 static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)
00464 {
00465     FFMContext *ffm = s->priv_data;
00466     int64_t pos_min, pos_max, pos;
00467     int64_t pts_min, pts_max, pts;
00468     double pos1;
00469 
00470 #ifdef DEBUG_SEEK
00471     av_log(s, AV_LOG_DEBUG, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);
00472 #endif
00473     /* find the position using linear interpolation (better than
00474        dichotomy in typical cases) */
00475     pos_min = FFM_PACKET_SIZE;
00476     pos_max = ffm->file_size - FFM_PACKET_SIZE;
00477     while (pos_min <= pos_max) {
00478         pts_min = get_dts(s, pos_min);
00479         pts_max = get_dts(s, pos_max);
00480         /* linear interpolation */
00481         pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /
00482             (double)(pts_max - pts_min);
00483         pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;
00484         if (pos <= pos_min)
00485             pos = pos_min;
00486         else if (pos >= pos_max)
00487             pos = pos_max;
00488         pts = get_dts(s, pos);
00489         /* check if we are lucky */
00490         if (pts == wanted_pts) {
00491             goto found;
00492         } else if (pts > wanted_pts) {
00493             pos_max = pos - FFM_PACKET_SIZE;
00494         } else {
00495             pos_min = pos + FFM_PACKET_SIZE;
00496         }
00497     }
00498     pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;
00499 
00500  found:
00501     ffm_seek1(s, pos);
00502 
00503     /* reset read state */
00504     ffm->read_state = READ_HEADER;
00505     ffm->packet_ptr = ffm->packet;
00506     ffm->packet_end = ffm->packet;
00507     ffm->first_packet = 1;
00508 
00509     return 0;
00510 }
00511 
00512 static int ffm_probe(AVProbeData *p)
00513 {
00514     if (
00515         p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&
00516         p->buf[3] == '1')
00517         return AVPROBE_SCORE_MAX + 1;
00518     return 0;
00519 }
00520 
00521 AVInputFormat ffm_demuxer = {
00522     "ffm",
00523     NULL_IF_CONFIG_SMALL("FFM (FFserver live feed) format"),
00524     sizeof(FFMContext),
00525     ffm_probe,
00526     ffm_read_header,
00527     ffm_read_packet,
00528     ffm_close,
00529     ffm_seek,
00530 };