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FFmpeg/libavformat/ffmdec.c

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  1. /*

  2.  * FFM (ffserver live feed) demuxer

  3.  * Copyright (c) 2001 Fabrice Bellard

  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 "libavutil/intfloat_readwrite.h"

  24. #include "avformat.h"

  25. #include "ffm.h"

  26. #if CONFIG_FFSERVER

  27. #include <unistd.h>

  28. 

  29. int64_t ffm_read_write_index(int fd)

  30. {

  31.     uint8_t buf[8];

  32. 

  33.     lseek(fd, 8, SEEK_SET);

  34.     if (read(fd, buf, 8) != 8)

  35.         return AVERROR(EIO);

  36.     return AV_RB64(buf);

  37. }

  38. 

  39. int ffm_write_write_index(int fd, int64_t pos)

  40. {

  41.     uint8_t buf[8];

  42.     int i;

  43. 

  44.     for(i=0;i<8;i++)

  45.         buf[i] = (pos >> (56 - i * 8)) & 0xff;

  46.     lseek(fd, 8, SEEK_SET);

  47.     if (write(fd, buf, 8) != 8)

  48.         return AVERROR(EIO);

  49.     return 8;

  50. }

  51. 

  52. void ffm_set_write_index(AVFormatContext *s, int64_t pos, int64_t file_size)

  53. {

  54.     FFMContext *ffm = s->priv_data;

  55.     ffm->write_index = pos;

  56.     ffm->file_size = file_size;

  57. }

  58. #endif // CONFIG_FFSERVER

  59. 

  60. static int ffm_is_avail_data(AVFormatContext *s, int size)

  61. {

  62.     FFMContext *ffm = s->priv_data;

  63.     int64_t pos, avail_size;

  64.     int len;

  65. 

  66.     len = ffm->packet_end - ffm->packet_ptr;

  67.     if (size <= len)

  68.         return 1;

  69.     pos = avio_tell(s->pb);

  70.     if (!ffm->write_index) {

  71.         if (pos == ffm->file_size)

  72.             return AVERROR_EOF;

  73.         avail_size = ffm->file_size - pos;

  74.     } else {

  75.     if (pos == ffm->write_index) {

  76.         /* exactly at the end of stream */

  77.         return AVERROR(EAGAIN);

  78.     } else if (pos < ffm->write_index) {

  79.         avail_size = ffm->write_index - pos;

  80.     } else {

  81.         avail_size = (ffm->file_size - pos) + (ffm->write_index - FFM_PACKET_SIZE);

  82.     }

  83.     }

  84.     avail_size = (avail_size / ffm->packet_size) * (ffm->packet_size - FFM_HEADER_SIZE) + len;

  85.     if (size <= avail_size)

  86.         return 1;

  87.     else

  88.         return AVERROR(EAGAIN);

  89. }

  90. 

  91. static int ffm_resync(AVFormatContext *s, int state)

  92. {

  93.     av_log(s, AV_LOG_ERROR, "resyncing\n");

  94.     while (state != PACKET_ID) {

  95.         if (url_feof(s->pb)) {

  96.             av_log(s, AV_LOG_ERROR, "cannot find FFM syncword\n");

  97.             return -1;

  98.         }

  99.         state = (state << 8) | avio_r8(s->pb);

  100.     }

  101.     return 0;

  102. }

  103. 

  104. /* first is true if we read the frame header */

  105. static int ffm_read_data(AVFormatContext *s,

  106.                          uint8_t *buf, int size, int header)

  107. {

  108.     FFMContext *ffm = s->priv_data;

  109.     AVIOContext *pb = s->pb;

  110.     int len, fill_size, size1, frame_offset, id;

  111. 

  112.     size1 = size;

  113.     while (size > 0) {

  114.     redo:

  115.         len = ffm->packet_end - ffm->packet_ptr;

  116.         if (len < 0)

  117.             return -1;

  118.         if (len > size)

  119.             len = size;

  120.         if (len == 0) {

  121.             if (avio_tell(pb) == ffm->file_size)

  122.                 avio_seek(pb, ffm->packet_size, SEEK_SET);

  123.     retry_read:

  124.             if (pb->buffer_size != ffm->packet_size) {

  125.                 int64_t tell = avio_tell(pb);

  126.                 url_setbufsize(pb, ffm->packet_size);

  127.                 avio_seek(pb, tell, SEEK_SET);

  128.             }

  129.             id = avio_rb16(pb); /* PACKET_ID */

  130.             if (id != PACKET_ID)

  131.                 if (ffm_resync(s, id) < 0)

  132.                     return -1;

  133.             fill_size = avio_rb16(pb);

  134.             ffm->dts = avio_rb64(pb);

  135.             frame_offset = avio_rb16(pb);

  136.             avio_read(pb, ffm->packet, ffm->packet_size - FFM_HEADER_SIZE);

  137.             ffm->packet_end = ffm->packet + (ffm->packet_size - FFM_HEADER_SIZE - fill_size);

  138.             if (ffm->packet_end < ffm->packet || frame_offset < 0)

  139.                 return -1;

  140.             /* if first packet or resynchronization packet, we must

  141.                handle it specifically */

  142.             if (ffm->first_packet || (frame_offset & 0x8000)) {

  143.                 if (!frame_offset) {

  144.                     /* This packet has no frame headers in it */

  145.                     if (avio_tell(pb) >= ffm->packet_size * 3) {

  146.                         avio_seek(pb, -ffm->packet_size * 2, SEEK_CUR);

  147.                         goto retry_read;

  148.                     }

  149.                     /* This is bad, we cannot find a valid frame header */

  150.                     return 0;

  151.                 }

  152.                 ffm->first_packet = 0;

  153.                 if ((frame_offset & 0x7fff) < FFM_HEADER_SIZE)

  154.                     return -1;

  155.                 ffm->packet_ptr = ffm->packet + (frame_offset & 0x7fff) - FFM_HEADER_SIZE;

  156.                 if (!header)

  157.                     break;

  158.             } else {

  159.                 ffm->packet_ptr = ffm->packet;

  160.             }

  161.             goto redo;

  162.         }

  163.         memcpy(buf, ffm->packet_ptr, len);

  164.         buf += len;

  165.         ffm->packet_ptr += len;

  166.         size -= len;

  167.         header = 0;

  168.     }

  169.     return size1 - size;

  170. }

  171. 

  172. /* ensure that acutal seeking happens between FFM_PACKET_SIZE

  173.    and file_size - FFM_PACKET_SIZE */

  174. static int64_t ffm_seek1(AVFormatContext *s, int64_t pos1)

  175. {

  176.     FFMContext *ffm = s->priv_data;

  177.     AVIOContext *pb = s->pb;

  178.     int64_t pos;

  179. 

  180.     pos = FFMIN(pos1, ffm->file_size - FFM_PACKET_SIZE);

  181.     pos = FFMAX(pos, FFM_PACKET_SIZE);

  182.     av_dlog(s, "seek to %"PRIx64" -> %"PRIx64"\n", pos1, pos);

  183.     return avio_seek(pb, pos, SEEK_SET);

  184. }

  185. 

  186. static int64_t get_dts(AVFormatContext *s, int64_t pos)

  187. {

  188.     AVIOContext *pb = s->pb;

  189.     int64_t dts;

  190. 

  191.     ffm_seek1(s, pos);

  192.     avio_skip(pb, 4);

  193.     dts = avio_rb64(pb);

  194.     av_dlog(s, "dts=%0.6f\n", dts / 1000000.0);

  195.     return dts;

  196. }

  197. 

  198. static void adjust_write_index(AVFormatContext *s)

  199. {

  200.     FFMContext *ffm = s->priv_data;

  201.     AVIOContext *pb = s->pb;

  202.     int64_t pts;

  203.     //int64_t orig_write_index = ffm->write_index;

  204.     int64_t pos_min, pos_max;

  205.     int64_t pts_start;

  206.     int64_t ptr = avio_tell(pb);

  207. 

  208. 

  209.     pos_min = 0;

  210.     pos_max = ffm->file_size - 2 * FFM_PACKET_SIZE;

  211. 

  212.     pts_start = get_dts(s, pos_min);

  213. 

  214.     pts = get_dts(s, pos_max);

  215. 

  216.     if (pts - 100000 > pts_start)

  217.         goto end;

  218. 

  219.     ffm->write_index = FFM_PACKET_SIZE;

  220. 

  221.     pts_start = get_dts(s, pos_min);

  222. 

  223.     pts = get_dts(s, pos_max);

  224. 

  225.     if (pts - 100000 <= pts_start) {

  226.         while (1) {

  227.             int64_t newpos;

  228.             int64_t newpts;

  229. 

  230.             newpos = ((pos_max + pos_min) / (2 * FFM_PACKET_SIZE)) * FFM_PACKET_SIZE;

  231. 

  232.             if (newpos == pos_min)

  233.                 break;

  234. 

  235.             newpts = get_dts(s, newpos);

  236. 

  237.             if (newpts - 100000 <= pts) {

  238.                 pos_max = newpos;

  239.                 pts = newpts;

  240.             } else {

  241.                 pos_min = newpos;

  242.             }

  243.         }

  244.         ffm->write_index += pos_max;

  245.     }

  246. 

  247.     //printf("Adjusted write index from %"PRId64" to %"PRId64": pts=%0.6f\n", orig_write_index, ffm->write_index, pts / 1000000.);

  248.     //printf("pts range %0.6f - %0.6f\n", get_dts(s, 0) / 1000000. , get_dts(s, ffm->file_size - 2 * FFM_PACKET_SIZE) / 1000000. );

  249. 

  250.  end:

  251.     avio_seek(pb, ptr, SEEK_SET);

  252. }

  253. 

  254. 

  255. static int ffm_close(AVFormatContext *s)

  256. {

  257.     int i;

  258. 

  259.     for (i = 0; i < s->nb_streams; i++)

  260.         av_freep(&s->streams[i]->codec->rc_eq);

  261. 

  262.     return 0;

  263. }

  264. 

  265. 

  266. static int ffm_read_header(AVFormatContext *s, AVFormatParameters *ap)

  267. {

  268.     FFMContext *ffm = s->priv_data;

  269.     AVStream *st;

  270.     AVIOContext *pb = s->pb;

  271.     AVCodecContext *codec;

  272.     int i, nb_streams;

  273.     uint32_t tag;

  274. 

  275.     /* header */

  276.     tag = avio_rl32(pb);

  277.     if (tag != MKTAG('F', 'F', 'M', '1'))

  278.         goto fail;

  279.     ffm->packet_size = avio_rb32(pb);

  280.     if (ffm->packet_size != FFM_PACKET_SIZE)

  281.         goto fail;

  282.     ffm->write_index = avio_rb64(pb);

  283.     /* get also filesize */

  284.     if (pb->seekable) {

  285.         ffm->file_size = avio_size(pb);

  286.         if (ffm->write_index)

  287.             adjust_write_index(s);

  288.     } else {

  289.         ffm->file_size = (UINT64_C(1) << 63) - 1;

  290.     }

  291. 

  292.     nb_streams = avio_rb32(pb);

  293.     avio_rb32(pb); /* total bitrate */

  294.     /* read each stream */

  295.     for(i=0;i<nb_streams;i++) {

  296.         char rc_eq_buf[128];

  297. 

  298.         st = av_new_stream(s, 0);

  299.         if (!st)

  300.             goto fail;

  301. 

  302.         av_set_pts_info(st, 64, 1, 1000000);

  303. 

  304.         codec = st->codec;

  305.         /* generic info */

  306.         codec->codec_id = avio_rb32(pb);

  307.         codec->codec_type = avio_r8(pb); /* codec_type */

  308.         codec->bit_rate = avio_rb32(pb);

  309.         codec->flags = avio_rb32(pb);

  310.         codec->flags2 = avio_rb32(pb);

  311.         codec->debug = avio_rb32(pb);

  312.         /* specific info */

  313.         switch(codec->codec_type) {

  314.         case AVMEDIA_TYPE_VIDEO:

  315.             codec->time_base.num = avio_rb32(pb);

  316.             codec->time_base.den = avio_rb32(pb);

  317.             codec->width = avio_rb16(pb);

  318.             codec->height = avio_rb16(pb);

  319.             codec->gop_size = avio_rb16(pb);

  320.             codec->pix_fmt = avio_rb32(pb);

  321.             codec->qmin = avio_r8(pb);

  322.             codec->qmax = avio_r8(pb);

  323.             codec->max_qdiff = avio_r8(pb);

  324.             codec->qcompress = avio_rb16(pb) / 10000.0;

  325.             codec->qblur = avio_rb16(pb) / 10000.0;

  326.             codec->bit_rate_tolerance = avio_rb32(pb);

  327.             codec->rc_eq = av_strdup(get_strz(pb, rc_eq_buf, sizeof(rc_eq_buf)));

  328.             codec->rc_max_rate = avio_rb32(pb);

  329.             codec->rc_min_rate = avio_rb32(pb);

  330.             codec->rc_buffer_size = avio_rb32(pb);

  331.             codec->i_quant_factor = av_int2dbl(avio_rb64(pb));

  332.             codec->b_quant_factor = av_int2dbl(avio_rb64(pb));

  333.             codec->i_quant_offset = av_int2dbl(avio_rb64(pb));

  334.             codec->b_quant_offset = av_int2dbl(avio_rb64(pb));

  335.             codec->dct_algo = avio_rb32(pb);

  336.             codec->strict_std_compliance = avio_rb32(pb);

  337.             codec->max_b_frames = avio_rb32(pb);

  338.             codec->luma_elim_threshold = avio_rb32(pb);

  339.             codec->chroma_elim_threshold = avio_rb32(pb);

  340.             codec->mpeg_quant = avio_rb32(pb);

  341.             codec->intra_dc_precision = avio_rb32(pb);

  342.             codec->me_method = avio_rb32(pb);

  343.             codec->mb_decision = avio_rb32(pb);

  344.             codec->nsse_weight = avio_rb32(pb);

  345.             codec->frame_skip_cmp = avio_rb32(pb);

  346.             codec->rc_buffer_aggressivity = av_int2dbl(avio_rb64(pb));

  347.             codec->codec_tag = avio_rb32(pb);

  348.             codec->thread_count = avio_r8(pb);

  349.             codec->coder_type = avio_rb32(pb);

  350.             codec->me_cmp = avio_rb32(pb);

  351.             codec->partitions = avio_rb32(pb);

  352.             codec->me_subpel_quality = avio_rb32(pb);

  353.             codec->me_range = avio_rb32(pb);

  354.             codec->keyint_min = avio_rb32(pb);

  355.             codec->scenechange_threshold = avio_rb32(pb);

  356.             codec->b_frame_strategy = avio_rb32(pb);

  357.             codec->qcompress = av_int2dbl(avio_rb64(pb));

  358.             codec->qblur = av_int2dbl(avio_rb64(pb));

  359.             codec->max_qdiff = avio_rb32(pb);

  360.             codec->refs = avio_rb32(pb);

  361.             codec->directpred = avio_rb32(pb);

  362.             break;

  363.         case AVMEDIA_TYPE_AUDIO:

  364.             codec->sample_rate = avio_rb32(pb);

  365.             codec->channels = avio_rl16(pb);

  366.             codec->frame_size = avio_rl16(pb);

  367.             codec->sample_fmt = (int16_t) avio_rl16(pb);

  368.             break;

  369.         default:

  370.             goto fail;

  371.         }

  372.         if (codec->flags & CODEC_FLAG_GLOBAL_HEADER) {

  373.             codec->extradata_size = avio_rb32(pb);

  374.             codec->extradata = av_malloc(codec->extradata_size);

  375.             if (!codec->extradata)

  376.                 return AVERROR(ENOMEM);

  377.             avio_read(pb, codec->extradata, codec->extradata_size);

  378.         }

  379.     }

  380. 

  381.     /* get until end of block reached */

  382.     while ((avio_tell(pb) % ffm->packet_size) != 0)

  383.         avio_r8(pb);

  384. 

  385.     /* init packet demux */

  386.     ffm->packet_ptr = ffm->packet;

  387.     ffm->packet_end = ffm->packet;

  388.     ffm->frame_offset = 0;

  389.     ffm->dts = 0;

  390.     ffm->read_state = READ_HEADER;

  391.     ffm->first_packet = 1;

  392.     return 0;

  393.  fail:

  394.     ffm_close(s);

  395.     return -1;

  396. }

  397. 

  398. /* return < 0 if eof */

  399. static int ffm_read_packet(AVFormatContext *s, AVPacket *pkt)

  400. {

  401.     int size;

  402.     FFMContext *ffm = s->priv_data;

  403.     int duration, ret;

  404. 

  405.     switch(ffm->read_state) {

  406.     case READ_HEADER:

  407.         if ((ret = ffm_is_avail_data(s, FRAME_HEADER_SIZE+4)) < 0)

  408.             return ret;

  409. 

  410.         av_dlog(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",

  411.                avio_tell(s->pb), s->pb->pos, ffm->write_index, ffm->file_size);

  412.         if (ffm_read_data(s, ffm->header, FRAME_HEADER_SIZE, 1) !=

  413.             FRAME_HEADER_SIZE)

  414.             return -1;

  415.         if (ffm->header[1] & FLAG_DTS)

  416.             if (ffm_read_data(s, ffm->header+16, 4, 1) != 4)

  417.                 return -1;

  418.         ffm->read_state = READ_DATA;

  419.         /* fall thru */

  420.     case READ_DATA:

  421.         size = AV_RB24(ffm->header + 2);

  422.         if ((ret = ffm_is_avail_data(s, size)) < 0)

  423.             return ret;

  424. 

  425.         duration = AV_RB24(ffm->header + 5);

  426. 

  427.         av_new_packet(pkt, size);

  428.         pkt->stream_index = ffm->header[0];

  429.         if ((unsigned)pkt->stream_index >= s->nb_streams) {

  430.             av_log(s, AV_LOG_ERROR, "invalid stream index %d\n", pkt->stream_index);

  431.             av_free_packet(pkt);

  432.             ffm->read_state = READ_HEADER;

  433.             return -1;

  434.         }

  435.         pkt->pos = avio_tell(s->pb);

  436.         if (ffm->header[1] & FLAG_KEY_FRAME)

  437.             pkt->flags |= AV_PKT_FLAG_KEY;

  438. 

  439.         ffm->read_state = READ_HEADER;

  440.         if (ffm_read_data(s, pkt->data, size, 0) != size) {

  441.             /* bad case: desynchronized packet. we cancel all the packet loading */

  442.             av_free_packet(pkt);

  443.             return -1;

  444.         }

  445.         pkt->pts = AV_RB64(ffm->header+8);

  446.         if (ffm->header[1] & FLAG_DTS)

  447.             pkt->dts = pkt->pts - AV_RB32(ffm->header+16);

  448.         else

  449.             pkt->dts = pkt->pts;

  450.         pkt->duration = duration;

  451.         break;

  452.     }

  453.     return 0;

  454. }

  455. 

  456. /* seek to a given time in the file. The file read pointer is

  457.    positioned at or before pts. XXX: the following code is quite

  458.    approximative */

  459. static int ffm_seek(AVFormatContext *s, int stream_index, int64_t wanted_pts, int flags)

  460. {

  461.     FFMContext *ffm = s->priv_data;

  462.     int64_t pos_min, pos_max, pos;

  463.     int64_t pts_min, pts_max, pts;

  464.     double pos1;

  465. 

  466.     av_dlog(s, "wanted_pts=%0.6f\n", wanted_pts / 1000000.0);

  467.     /* find the position using linear interpolation (better than

  468.        dichotomy in typical cases) */

  469.     if (ffm->write_index && ffm->write_index < ffm->file_size) {

  470.         if (get_dts(s, FFM_PACKET_SIZE) < wanted_pts) {

  471.             pos_min = FFM_PACKET_SIZE;

  472.             pos_max = ffm->write_index - FFM_PACKET_SIZE;

  473.         } else {

  474.             pos_min = ffm->write_index;

  475.             pos_max = ffm->file_size - FFM_PACKET_SIZE;

  476.         }

  477.     } else {

  478.         pos_min = FFM_PACKET_SIZE;

  479.         pos_max = ffm->file_size - FFM_PACKET_SIZE;

  480.     }

  481.     while (pos_min <= pos_max) {

  482.         pts_min = get_dts(s, pos_min);

  483.         pts_max = get_dts(s, pos_max);

  484.         if (pts_min > wanted_pts || pts_max < wanted_pts) {

  485.             pos = pts_min > wanted_pts ? pos_min : pos_max;

  486.             goto found;

  487.         }

  488.         /* linear interpolation */

  489.         pos1 = (double)(pos_max - pos_min) * (double)(wanted_pts - pts_min) /

  490.             (double)(pts_max - pts_min);

  491.         pos = (((int64_t)pos1) / FFM_PACKET_SIZE) * FFM_PACKET_SIZE;

  492.         if (pos <= pos_min)

  493.             pos = pos_min;

  494.         else if (pos >= pos_max)

  495.             pos = pos_max;

  496.         pts = get_dts(s, pos);

  497.         /* check if we are lucky */

  498.         if (pts == wanted_pts) {

  499.             goto found;

  500.         } else if (pts > wanted_pts) {

  501.             pos_max = pos - FFM_PACKET_SIZE;

  502.         } else {

  503.             pos_min = pos + FFM_PACKET_SIZE;

  504.         }

  505.     }

  506.     pos = (flags & AVSEEK_FLAG_BACKWARD) ? pos_min : pos_max;

  507. 

  508.  found:

  509.     if (ffm_seek1(s, pos) < 0)

  510.         return -1;

  511. 

  512.     /* reset read state */

  513.     ffm->read_state = READ_HEADER;

  514.     ffm->packet_ptr = ffm->packet;

  515.     ffm->packet_end = ffm->packet;

  516.     ffm->first_packet = 1;

  517. 

  518.     return 0;

  519. }

  520. 

  521. static int ffm_probe(AVProbeData *p)

  522. {

  523.     if (

  524.         p->buf[0] == 'F' && p->buf[1] == 'F' && p->buf[2] == 'M' &&

  525.         p->buf[3] == '1')

  526.         return AVPROBE_SCORE_MAX + 1;

  527.     return 0;

  528. }

  529. 

  530. AVInputFormat ff_ffm_demuxer = {

  531.     .name           = "ffm",

  532.     .long_name      = NULL_IF_CONFIG_SMALL("FFM (FFserver live feed) format"),

  533.     .priv_data_size = sizeof(FFMContext),

  534.     .read_probe     = ffm_probe,

  535.     .read_header    = ffm_read_header,

  536.     .read_packet    = ffm_read_packet,

  537.     .read_close     = ffm_close,

  538.     .read_seek      = ffm_seek,

  539. };