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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.h"

  24. #include "avformat.h"

  25. #include "internal.h"

  26. #include "ffm.h"

  27. #include "avio_internal.h"

  28. #if CONFIG_FFSERVER

  29. #include <unistd.h>

  30. 

  31. int64_t ffm_read_write_index(int fd)

  32. {

  33.     uint8_t buf[8];

  34. 

  35.     lseek(fd, 8, SEEK_SET);

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

  37.         return AVERROR(EIO);

  38.     return AV_RB64(buf);

  39. }

  40. 

  41. int ffm_write_write_index(int fd, int64_t pos)

  42. {

  43.     uint8_t buf[8];

  44.     int i;

  45. 

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

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

  48.     lseek(fd, 8, SEEK_SET);

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

  50.         return AVERROR(EIO);

  51.     return 8;

  52. }

  53. 

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

  55. {

  56.     FFMContext *ffm = s->priv_data;

  57.     ffm->write_index = pos;

  58.     ffm->file_size = file_size;

  59. }

  60. #endif // CONFIG_FFSERVER

  61. 

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

  63. {

  64.     FFMContext *ffm = s->priv_data;

  65.     int64_t pos, avail_size;

  66.     int len;

  67. 

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

  69.     if (size <= len)

  70.         return 1;

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

  72.     if (!ffm->write_index) {

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

  74.             return AVERROR_EOF;

  75.         avail_size = ffm->file_size - pos;

  76.     } else {

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

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

  79.         return AVERROR(EAGAIN);

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

  81.         avail_size = ffm->write_index - pos;

  82.     } else {

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

  84.     }

  85.     }

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

  87.     if (size <= avail_size)

  88.         return 1;

  89.     else

  90.         return AVERROR(EAGAIN);

  91. }

  92. 

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

  94. {

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

  96.     while (state != PACKET_ID) {

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

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

  99.             return -1;

  100.         }

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

  102.     }

  103.     return 0;

  104. }

  105. 

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

  107. static int ffm_read_data(AVFormatContext *s,

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

  109. {

  110.     FFMContext *ffm = s->priv_data;

  111.     AVIOContext *pb = s->pb;

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

  113. 

  114.     size1 = size;

  115.     while (size > 0) {

  116.     redo:

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

  118.         if (len < 0)

  119.             return -1;

  120.         if (len > size)

  121.             len = size;

  122.         if (len == 0) {

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

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

  125.     retry_read:

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

  127.                 int64_t tell = avio_tell(pb);

  128.                 ffio_set_buf_size(pb, ffm->packet_size);

  129.                 avio_seek(pb, tell, SEEK_SET);

  130.             }

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

  132.             if (id != PACKET_ID)

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

  134.                     return -1;

  135.             fill_size = avio_rb16(pb);

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

  137.             frame_offset = avio_rb16(pb);

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

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

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

  141.                 return -1;

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

  143.                handle it specifically */

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

  145.                 if (!frame_offset) {

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

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

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

  149.                         goto retry_read;

  150.                     }

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

  152.                     return 0;

  153.                 }

  154.                 ffm->first_packet = 0;

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

  156.                     return -1;

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

  158.                 if (!header)

  159.                     break;

  160.             } else {

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

  162.             }

  163.             goto redo;

  164.         }

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

  166.         buf += len;

  167.         ffm->packet_ptr += len;

  168.         size -= len;

  169.         header = 0;

  170.     }

  171.     return size1 - size;

  172. }

  173. 

  174. /* ensure that acutal seeking happens between FFM_PACKET_SIZE

  175.    and file_size - FFM_PACKET_SIZE */

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

  177. {

  178.     FFMContext *ffm = s->priv_data;

  179.     AVIOContext *pb = s->pb;

  180.     int64_t pos;

  181. 

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

  183.     pos = FFMAX(pos, FFM_PACKET_SIZE);

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

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

  186. }

  187. 

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

  189. {

  190.     AVIOContext *pb = s->pb;

  191.     int64_t dts;

  192. 

  193.     ffm_seek1(s, pos);

  194.     avio_skip(pb, 4);

  195.     dts = avio_rb64(pb);

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

  197.     return dts;

  198. }

  199. 

  200. static void adjust_write_index(AVFormatContext *s)

  201. {

  202.     FFMContext *ffm = s->priv_data;

  203.     AVIOContext *pb = s->pb;

  204.     int64_t pts;

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

  206.     int64_t pos_min, pos_max;

  207.     int64_t pts_start;

  208.     int64_t ptr = avio_tell(pb);

  209. 

  210. 

  211.     pos_min = 0;

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

  213. 

  214.     pts_start = get_dts(s, pos_min);

  215. 

  216.     pts = get_dts(s, pos_max);

  217. 

  218.     if (pts - 100000 > pts_start)

  219.         goto end;

  220. 

  221.     ffm->write_index = FFM_PACKET_SIZE;

  222. 

  223.     pts_start = get_dts(s, pos_min);

  224. 

  225.     pts = get_dts(s, pos_max);

  226. 

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

  228.         while (1) {

  229.             int64_t newpos;

  230.             int64_t newpts;

  231. 

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

  233. 

  234.             if (newpos == pos_min)

  235.                 break;

  236. 

  237.             newpts = get_dts(s, newpos);

  238. 

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

  240.                 pos_max = newpos;

  241.                 pts = newpts;

  242.             } else {

  243.                 pos_min = newpos;

  244.             }

  245.         }

  246.         ffm->write_index += pos_max;

  247.     }

  248. 

  249.  end:

  250.     avio_seek(pb, ptr, SEEK_SET);

  251. }

  252. 

  253. 

  254. static int ffm_close(AVFormatContext *s)

  255. {

  256.     int i;

  257. 

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

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

  260. 

  261.     return 0;

  262. }

  263. 

  264. 

  265. static int ffm_read_header(AVFormatContext *s)

  266. {

  267.     FFMContext *ffm = s->priv_data;

  268.     AVStream *st;

  269.     AVIOContext *pb = s->pb;

  270.     AVCodecContext *codec;

  271.     int i, nb_streams;

  272.     uint32_t tag;

  273. 

  274.     /* header */

  275.     tag = avio_rl32(pb);

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

  277.         goto fail;

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

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

  280.         goto fail;

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

  282.     /* get also filesize */

  283.     if (pb->seekable) {

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

  285.         if (ffm->write_index && 0)

  286.             adjust_write_index(s);

  287.     } else {

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

  289.     }

  290. 

  291.     nb_streams = avio_rb32(pb);

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

  293.     /* read each stream */

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

  295.         char rc_eq_buf[128];

  296. 

  297.         st = avformat_new_stream(s, NULL);

  298.         if (!st)

  299.             goto fail;

  300. 

  301.         avpriv_set_pts_info(st, 64, 1, 1000000);

  302. 

  303.         codec = st->codec;

  304.         /* generic info */

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

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

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

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

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

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

  311.         /* specific info */

  312.         switch(codec->codec_type) {

  313.         case AVMEDIA_TYPE_VIDEO:

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

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

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

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

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

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

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

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

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

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

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

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

  326.             avio_get_str(pb, INT_MAX, rc_eq_buf, sizeof(rc_eq_buf));

  327.             codec->rc_eq = av_strdup(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_int2double(avio_rb64(pb));

  332.             codec->b_quant_factor = av_int2double(avio_rb64(pb));

  333.             codec->i_quant_offset = av_int2double(avio_rb64(pb));

  334.             codec->b_quant_offset = av_int2double(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->mpeg_quant = avio_rb32(pb);

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

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

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

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

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

  344.             codec->rc_buffer_aggressivity = av_int2double(avio_rb64(pb));

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

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

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

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

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

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

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

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

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

  354.             codec->qcompress = av_int2double(avio_rb64(pb));

  355.             codec->qblur = av_int2double(avio_rb64(pb));

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

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

  358.             break;

  359.         case AVMEDIA_TYPE_AUDIO:

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

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

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

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

  364.             break;

  365.         default:

  366.             goto fail;

  367.         }

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

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

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

  371.             if (!codec->extradata)

  372.                 return AVERROR(ENOMEM);

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

  374.         }

  375.     }

  376. 

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

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

  379.         avio_r8(pb);

  380. 

  381.     /* init packet demux */

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

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

  384.     ffm->frame_offset = 0;

  385.     ffm->dts = 0;

  386.     ffm->read_state = READ_HEADER;

  387.     ffm->first_packet = 1;

  388.     return 0;

  389.  fail:

  390.     ffm_close(s);

  391.     return -1;

  392. }

  393. 

  394. /* return < 0 if eof */

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

  396. {

  397.     int size;

  398.     FFMContext *ffm = s->priv_data;

  399.     int duration, ret;

  400. 

  401.     switch(ffm->read_state) {

  402.     case READ_HEADER:

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

  404.             return ret;

  405. 

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

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

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

  409.             FRAME_HEADER_SIZE)

  410.             return -1;

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

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

  413.                 return -1;

  414.         ffm->read_state = READ_DATA;

  415.         /* fall thru */

  416.     case READ_DATA:

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

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

  419.             return ret;

  420. 

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

  422. 

  423.         av_new_packet(pkt, size);

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

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

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

  427.             av_free_packet(pkt);

  428.             ffm->read_state = READ_HEADER;

  429.             return -1;

  430.         }

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

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

  433.             pkt->flags |= AV_PKT_FLAG_KEY;

  434. 

  435.         ffm->read_state = READ_HEADER;

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

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

  438.             av_free_packet(pkt);

  439.             return -1;

  440.         }

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

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

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

  444.         else

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

  446.         pkt->duration = duration;

  447.         break;

  448.     }

  449.     return 0;

  450. }

  451. 

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

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

  454.    approximative */

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

  456. {

  457.     FFMContext *ffm = s->priv_data;

  458.     int64_t pos_min, pos_max, pos;

  459.     int64_t pts_min, pts_max, pts;

  460.     double pos1;

  461. 

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

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

  464.        dichotomy in typical cases) */

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

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

  467.             pos_min = FFM_PACKET_SIZE;

  468.             pos_max = ffm->write_index - FFM_PACKET_SIZE;

  469.         } else {

  470.             pos_min = ffm->write_index;

  471.             pos_max = ffm->file_size - FFM_PACKET_SIZE;

  472.         }

  473.     } else {

  474.         pos_min = FFM_PACKET_SIZE;

  475.         pos_max = ffm->file_size - FFM_PACKET_SIZE;

  476.     }

  477.     while (pos_min <= pos_max) {

  478.         pts_min = get_dts(s, pos_min);

  479.         pts_max = get_dts(s, pos_max);

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

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

  482.             goto found;

  483.         }

  484.         /* linear interpolation */

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

  486.             (double)(pts_max - pts_min);

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

  488.         if (pos <= pos_min)

  489.             pos = pos_min;

  490.         else if (pos >= pos_max)

  491.             pos = pos_max;

  492.         pts = get_dts(s, pos);

  493.         /* check if we are lucky */

  494.         if (pts == wanted_pts) {

  495.             goto found;

  496.         } else if (pts > wanted_pts) {

  497.             pos_max = pos - FFM_PACKET_SIZE;

  498.         } else {

  499.             pos_min = pos + FFM_PACKET_SIZE;

  500.         }

  501.     }

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

  503. 

  504.  found:

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

  506.         return -1;

  507. 

  508.     /* reset read state */

  509.     ffm->read_state = READ_HEADER;

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

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

  512.     ffm->first_packet = 1;

  513. 

  514.     return 0;

  515. }

  516. 

  517. static int ffm_probe(AVProbeData *p)

  518. {

  519.     if (

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

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

  522.         return AVPROBE_SCORE_MAX + 1;

  523.     return 0;

  524. }

  525. 

  526. AVInputFormat ff_ffm_demuxer = {

  527.     .name           = "ffm",

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

  529.     .priv_data_size = sizeof(FFMContext),

  530.     .read_probe     = ffm_probe,

  531.     .read_header    = ffm_read_header,

  532.     .read_packet    = ffm_read_packet,

  533.     .read_close     = ffm_close,

  534.     .read_seek      = ffm_seek,

  535. };