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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. 

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

  30. {

  31.     FFMContext *ffm = s->priv_data;

  32.     int64_t pos, avail_size;

  33.     int len;

  34. 

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

  36.     if (size <= len)

  37.         return 1;

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

  39.     if (!ffm->write_index) {

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

  41.             return AVERROR_EOF;

  42.         avail_size = ffm->file_size - pos;

  43.     } else {

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

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

  46.         return AVERROR(EAGAIN);

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

  48.         avail_size = ffm->write_index - pos;

  49.     } else {

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

  51.     }

  52.     }

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

  54.     if (size <= avail_size)

  55.         return 1;

  56.     else

  57.         return AVERROR(EAGAIN);

  58. }

  59. 

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

  61. {

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

  63.     while (state != PACKET_ID) {

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

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

  66.             return -1;

  67.         }

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

  69.     }

  70.     return 0;

  71. }

  72. 

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

  74. static int ffm_read_data(AVFormatContext *s,

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

  76. {

  77.     FFMContext *ffm = s->priv_data;

  78.     AVIOContext *pb = s->pb;

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

  80. 

  81.     size1 = size;

  82.     while (size > 0) {

  83.     redo:

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

  85.         if (len < 0)

  86.             return -1;

  87.         if (len > size)

  88.             len = size;

  89.         if (len == 0) {

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

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

  92.     retry_read:

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

  94.                 int64_t tell = avio_tell(pb);

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

  96.                 avio_seek(pb, tell, SEEK_SET);

  97.             }

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

  99.             if (id != PACKET_ID)

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

  101.                     return -1;

  102.             fill_size = avio_rb16(pb);

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

  104.             frame_offset = avio_rb16(pb);

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

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

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

  108.                 return -1;

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

  110.                handle it specifically */

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

  112.                 if (!frame_offset) {

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

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

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

  116.                         goto retry_read;

  117.                     }

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

  119.                     return 0;

  120.                 }

  121.                 ffm->first_packet = 0;

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

  123.                     return -1;

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

  125.                 if (!header)

  126.                     break;

  127.             } else {

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

  129.             }

  130.             goto redo;

  131.         }

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

  133.         buf += len;

  134.         ffm->packet_ptr += len;

  135.         size -= len;

  136.         header = 0;

  137.     }

  138.     return size1 - size;

  139. }

  140. 

  141. /* ensure that acutal seeking happens between FFM_PACKET_SIZE

  142.    and file_size - FFM_PACKET_SIZE */

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

  144. {

  145.     FFMContext *ffm = s->priv_data;

  146.     AVIOContext *pb = s->pb;

  147.     int64_t pos;

  148. 

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

  150.     pos = FFMAX(pos, FFM_PACKET_SIZE);

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

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

  153. }

  154. 

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

  156. {

  157.     AVIOContext *pb = s->pb;

  158.     int64_t dts;

  159. 

  160.     ffm_seek1(s, pos);

  161.     avio_skip(pb, 4);

  162.     dts = avio_rb64(pb);

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

  164.     return dts;

  165. }

  166. 

  167. static void adjust_write_index(AVFormatContext *s)

  168. {

  169.     FFMContext *ffm = s->priv_data;

  170.     AVIOContext *pb = s->pb;

  171.     int64_t pts;

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

  173.     int64_t pos_min, pos_max;

  174.     int64_t pts_start;

  175.     int64_t ptr = avio_tell(pb);

  176. 

  177. 

  178.     pos_min = 0;

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

  180. 

  181.     pts_start = get_dts(s, pos_min);

  182. 

  183.     pts = get_dts(s, pos_max);

  184. 

  185.     if (pts - 100000 > pts_start)

  186.         goto end;

  187. 

  188.     ffm->write_index = FFM_PACKET_SIZE;

  189. 

  190.     pts_start = get_dts(s, pos_min);

  191. 

  192.     pts = get_dts(s, pos_max);

  193. 

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

  195.         while (1) {

  196.             int64_t newpos;

  197.             int64_t newpts;

  198. 

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

  200. 

  201.             if (newpos == pos_min)

  202.                 break;

  203. 

  204.             newpts = get_dts(s, newpos);

  205. 

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

  207.                 pos_max = newpos;

  208.                 pts = newpts;

  209.             } else {

  210.                 pos_min = newpos;

  211.             }

  212.         }

  213.         ffm->write_index += pos_max;

  214.     }

  215. 

  216.  end:

  217.     avio_seek(pb, ptr, SEEK_SET);

  218. }

  219. 

  220. 

  221. static int ffm_close(AVFormatContext *s)

  222. {

  223.     int i;

  224. 

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

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

  227. 

  228.     return 0;

  229. }

  230. 

  231. 

  232. static int ffm_read_header(AVFormatContext *s)

  233. {

  234.     FFMContext *ffm = s->priv_data;

  235.     AVStream *st;

  236.     AVIOContext *pb = s->pb;

  237.     AVCodecContext *codec;

  238.     int i, nb_streams;

  239.     uint32_t tag;

  240. 

  241.     /* header */

  242.     tag = avio_rl32(pb);

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

  244.         goto fail;

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

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

  247.         goto fail;

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

  249.     /* get also filesize */

  250.     if (pb->seekable) {

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

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

  253.             adjust_write_index(s);

  254.     } else {

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

  256.     }

  257. 

  258.     nb_streams = avio_rb32(pb);

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

  260.     /* read each stream */

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

  262.         char rc_eq_buf[128];

  263. 

  264.         st = avformat_new_stream(s, NULL);

  265.         if (!st)

  266.             goto fail;

  267. 

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

  269. 

  270.         codec = st->codec;

  271.         /* generic info */

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

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

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

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

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

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

  278.         /* specific info */

  279.         switch(codec->codec_type) {

  280.         case AVMEDIA_TYPE_VIDEO:

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

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

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

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

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

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

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

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

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

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

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

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

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

  294.             codec->rc_eq = av_strdup(rc_eq_buf);

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

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

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

  298.             codec->i_quant_factor = av_int2double(avio_rb64(pb));

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

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

  301.             codec->b_quant_offset = av_int2double(avio_rb64(pb));

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  325.             break;

  326.         case AVMEDIA_TYPE_AUDIO:

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

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

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

  330.             break;

  331.         default:

  332.             goto fail;

  333.         }

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

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

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

  337.             if (!codec->extradata)

  338.                 return AVERROR(ENOMEM);

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

  340.         }

  341.     }

  342. 

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

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

  345.         avio_r8(pb);

  346. 

  347.     /* init packet demux */

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

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

  350.     ffm->frame_offset = 0;

  351.     ffm->dts = 0;

  352.     ffm->read_state = READ_HEADER;

  353.     ffm->first_packet = 1;

  354.     return 0;

  355.  fail:

  356.     ffm_close(s);

  357.     return -1;

  358. }

  359. 

  360. /* return < 0 if eof */

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

  362. {

  363.     int size;

  364.     FFMContext *ffm = s->priv_data;

  365.     int duration, ret;

  366. 

  367.     switch(ffm->read_state) {

  368.     case READ_HEADER:

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

  370.             return ret;

  371. 

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

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

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

  375.             FRAME_HEADER_SIZE)

  376.             return -1;

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

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

  379.                 return -1;

  380.         ffm->read_state = READ_DATA;

  381.         /* fall thru */

  382.     case READ_DATA:

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

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

  385.             return ret;

  386. 

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

  388. 

  389.         if (av_new_packet(pkt, size) < 0) {

  390.             return AVERROR(ENOMEM);

  391.         }

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

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

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

  395.             av_free_packet(pkt);

  396.             ffm->read_state = READ_HEADER;

  397.             return -1;

  398.         }

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

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

  401.             pkt->flags |= AV_PKT_FLAG_KEY;

  402. 

  403.         ffm->read_state = READ_HEADER;

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

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

  406.             av_free_packet(pkt);

  407.             return -1;

  408.         }

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

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

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

  412.         else

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

  414.         pkt->duration = duration;

  415.         break;

  416.     }

  417.     return 0;

  418. }

  419. 

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

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

  422.    approximative */

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

  424. {

  425.     FFMContext *ffm = s->priv_data;

  426.     int64_t pos_min, pos_max, pos;

  427.     int64_t pts_min, pts_max, pts;

  428.     double pos1;

  429. 

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

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

  432.        dichotomy in typical cases) */

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

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

  435.             pos_min = FFM_PACKET_SIZE;

  436.             pos_max = ffm->write_index - FFM_PACKET_SIZE;

  437.         } else {

  438.             pos_min = ffm->write_index;

  439.             pos_max = ffm->file_size - FFM_PACKET_SIZE;

  440.         }

  441.     } else {

  442.         pos_min = FFM_PACKET_SIZE;

  443.         pos_max = ffm->file_size - FFM_PACKET_SIZE;

  444.     }

  445.     while (pos_min <= pos_max) {

  446.         pts_min = get_dts(s, pos_min);

  447.         pts_max = get_dts(s, pos_max);

  448.         if (pts_min > wanted_pts || pts_max <= wanted_pts) {

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

  450.             goto found;

  451.         }

  452.         /* linear interpolation */

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

  454.             (double)(pts_max - pts_min);

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

  456.         if (pos <= pos_min)

  457.             pos = pos_min;

  458.         else if (pos >= pos_max)

  459.             pos = pos_max;

  460.         pts = get_dts(s, pos);

  461.         /* check if we are lucky */

  462.         if (pts == wanted_pts) {

  463.             goto found;

  464.         } else if (pts > wanted_pts) {

  465.             pos_max = pos - FFM_PACKET_SIZE;

  466.         } else {

  467.             pos_min = pos + FFM_PACKET_SIZE;

  468.         }

  469.     }

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

  471. 

  472.  found:

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

  474.         return -1;

  475. 

  476.     /* reset read state */

  477.     ffm->read_state = READ_HEADER;

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

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

  480.     ffm->first_packet = 1;

  481. 

  482.     return 0;

  483. }

  484. 

  485. static int ffm_probe(AVProbeData *p)

  486. {

  487.     if (

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

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

  490.         return AVPROBE_SCORE_MAX + 1;

  491.     return 0;

  492. }

  493. 

  494. AVInputFormat ff_ffm_demuxer = {

  495.     .name           = "ffm",

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

  497.     .priv_data_size = sizeof(FFMContext),

  498.     .read_probe     = ffm_probe,

  499.     .read_header    = ffm_read_header,

  500.     .read_packet    = ffm_read_packet,

  501.     .read_close     = ffm_close,

  502.     .read_seek      = ffm_seek,

  503. };