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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 <stdint.h>

  23. 

  24. #include "libavutil/internal.h"

  25. #include "libavutil/intreadwrite.h"

  26. #include "libavutil/intfloat.h"

  27. #include "libavutil/opt.h"

  28. #include "libavutil/avassert.h"

  29. #include "libavutil/avstring.h"

  30. #include "avformat.h"

  31. #include "internal.h"

  32. #include "ffm.h"

  33. #include "avio_internal.h"

  34. 

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

  36. {

  37.     FFMContext *ffm = s->priv_data;

  38.     int64_t pos, avail_size;

  39.     int len;

  40. 

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

  42.     if (size <= len)

  43.         return 1;

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

  45.     if (!ffm->write_index) {

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

  47.             return AVERROR_EOF;

  48.         avail_size = ffm->file_size - pos;

  49.     } else {

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

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

  52.         if (ffm->server_attached)

  53.             return AVERROR(EAGAIN);

  54.         else

  55.             return AVERROR_INVALIDDATA;

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

  57.         avail_size = ffm->write_index - pos;

  58.     } else {

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

  60.     }

  61.     }

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

  63.     if (size <= avail_size)

  64.         return 1;

  65.     else if (ffm->server_attached)

  66.         return AVERROR(EAGAIN);

  67.     else

  68.         return AVERROR_INVALIDDATA;

  69. }

  70. 

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

  72. {

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

  74.     while (state != PACKET_ID) {

  75.         if (avio_feof(s->pb)) {

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

  77.             return -1;

  78.         }

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

  80.     }

  81.     return 0;

  82. }

  83. 

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

  85. static int ffm_read_data(AVFormatContext *s,

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

  87. {

  88.     FFMContext *ffm = s->priv_data;

  89.     AVIOContext *pb = s->pb;

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

  91.     int64_t last_pos = -1;

  92. 

  93.     size1 = size;

  94.     while (size > 0) {

  95.     redo:

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

  97.         if (len < 0)

  98.             return -1;

  99.         if (len > size)

  100.             len = size;

  101.         if (len == 0) {

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

  103.                 if (ffm->server_attached)

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

  105.                 else

  106.                     return AVERROR_EOF;

  107.     retry_read:

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

  109.                 int64_t tell = avio_tell(pb);

  110.                 int ret = ffio_set_buf_size(pb, ffm->packet_size);

  111.                 if (ret < 0)

  112.                     return ret;

  113.                 avio_seek(pb, tell, SEEK_SET);

  114.             }

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

  116.             if (id != PACKET_ID) {

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

  118.                     return -1;

  119.                 last_pos = avio_tell(pb);

  120.             }

  121.             fill_size = avio_rb16(pb);

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

  123.             frame_offset = avio_rb16(pb);

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

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

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

  127.                 return -1;

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

  129.                handle it specifically */

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

  131.                 if (!frame_offset) {

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

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

  134.                         int64_t seekback = FFMIN(ffm->packet_size * 2LL, avio_tell(pb) - last_pos);

  135.                         seekback = FFMAX(seekback, 0);

  136.                         avio_seek(pb, -seekback, SEEK_CUR);

  137.                         goto retry_read;

  138.                     }

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

  140.                     return 0;

  141.                 }

  142.                 ffm->first_packet = 0;

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

  144.                     return -1;

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

  146.                 if (!header)

  147.                     break;

  148.             } else {

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

  150.             }

  151.             goto redo;

  152.         }

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

  154.         buf += len;

  155.         ffm->packet_ptr += len;

  156.         size -= len;

  157.         header = 0;

  158.     }

  159.     return size1 - size;

  160. }

  161. 

  162. /* ensure that actual seeking happens between FFM_PACKET_SIZE

  163.    and file_size - FFM_PACKET_SIZE */

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

  165. {

  166.     FFMContext *ffm = s->priv_data;

  167.     AVIOContext *pb = s->pb;

  168.     int64_t pos;

  169. 

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

  171.     pos = FFMAX(pos, FFM_PACKET_SIZE);

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

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

  174. }

  175. 

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

  177. {

  178.     AVIOContext *pb = s->pb;

  179.     int64_t dts;

  180. 

  181.     ffm_seek1(s, pos);

  182.     avio_skip(pb, 4);

  183.     dts = avio_rb64(pb);

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

  185.     return dts;

  186. }

  187. 

  188. static void adjust_write_index(AVFormatContext *s)

  189. {

  190.     FFMContext *ffm = s->priv_data;

  191.     AVIOContext *pb = s->pb;

  192.     int64_t pts;

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

  194.     int64_t pos_min, pos_max;

  195.     int64_t pts_start;

  196.     int64_t ptr = avio_tell(pb);

  197. 

  198. 

  199.     pos_min = 0;

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

  201. 

  202.     pts_start = get_dts(s, pos_min);

  203. 

  204.     pts = get_dts(s, pos_max);

  205. 

  206.     if (pts - 100000 > pts_start)

  207.         goto end;

  208. 

  209.     ffm->write_index = FFM_PACKET_SIZE;

  210. 

  211.     pts_start = get_dts(s, pos_min);

  212. 

  213.     pts = get_dts(s, pos_max);

  214. 

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

  216.         while (1) {

  217.             int64_t newpos;

  218.             int64_t newpts;

  219. 

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

  221. 

  222.             if (newpos == pos_min)

  223.                 break;

  224. 

  225.             newpts = get_dts(s, newpos);

  226. 

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

  228.                 pos_max = newpos;

  229.                 pts = newpts;

  230.             } else {

  231.                 pos_min = newpos;

  232.             }

  233.         }

  234.         ffm->write_index += pos_max;

  235.     }

  236. 

  237.  end:

  238.     avio_seek(pb, ptr, SEEK_SET);

  239. }

  240. 

  241. 

  242. static int ffm_close(AVFormatContext *s)

  243. {

  244.     int i;

  245. 

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

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

  248. 

  249.     return 0;

  250. }

  251. 

  252. static int ffm_append_recommended_configuration(AVStream *st, char **conf)

  253. {

  254.     int ret;

  255.     size_t newsize;

  256.     av_assert0(conf && st);

  257.     if (!*conf)

  258.         return 0;

  259.     if (!st->recommended_encoder_configuration) {

  260.         st->recommended_encoder_configuration = *conf;

  261.         *conf = 0;

  262.         return 0;

  263.     }

  264.     newsize = strlen(*conf) + strlen(st->recommended_encoder_configuration) + 2;

  265.     if ((ret = av_reallocp(&st->recommended_encoder_configuration, newsize)) < 0)

  266.         return ret;

  267.     av_strlcat(st->recommended_encoder_configuration, ",", newsize);

  268.     av_strlcat(st->recommended_encoder_configuration, *conf, newsize);

  269.     av_freep(conf);

  270.     return 0;

  271. }

  272. 

  273. static int ffm2_read_header(AVFormatContext *s)

  274. {

  275.     FFMContext *ffm = s->priv_data;

  276.     AVStream *st;

  277.     AVIOContext *pb = s->pb;

  278.     AVCodecContext *codec;

  279.     int ret;

  280.     int f_main = 0, f_cprv = -1, f_stvi = -1, f_stau = -1;

  281.     AVCodec *enc;

  282.     char *buffer;

  283. 

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

  285.     if (ffm->packet_size != FFM_PACKET_SIZE) {

  286.         av_log(s, AV_LOG_ERROR, "Invalid packet size %d, expected size was %d\n",

  287.                ffm->packet_size, FFM_PACKET_SIZE);

  288.         ret = AVERROR_INVALIDDATA;

  289.         goto fail;

  290.     }

  291. 

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

  293.     /* get also filesize */

  294.     if (pb->seekable) {

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

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

  297.             adjust_write_index(s);

  298.     } else {

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

  300.     }

  301. 

  302.     while(!avio_feof(pb)) {

  303.         unsigned id = avio_rb32(pb);

  304.         unsigned size = avio_rb32(pb);

  305.         int64_t next = avio_tell(pb) + size;

  306.         char rc_eq_buf[128];

  307. 

  308.         if(!id)

  309.             break;

  310. 

  311.         switch(id) {

  312.         case MKBETAG('M', 'A', 'I', 'N'):

  313.             if (f_main++) {

  314.                 ret = AVERROR(EINVAL);

  315.                 goto fail;

  316.             }

  317.             avio_rb32(pb); /* nb_streams */

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

  319.             break;

  320.         case MKBETAG('C', 'O', 'M', 'M'):

  321.             f_cprv = f_stvi = f_stau = 0;

  322.             st = avformat_new_stream(s, NULL);

  323.             if (!st) {

  324.                 ret = AVERROR(ENOMEM);

  325.                 goto fail;

  326.             }

  327. 

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

  329. 

  330.             codec = st->codec;

  331.             /* generic info */

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

  333.             codec->codec_type = avio_r8(pb);

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

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

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

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

  338.             if (codec->flags & AV_CODEC_FLAG_GLOBAL_HEADER) {

  339.                 if (ff_get_extradata(codec, pb, avio_rb32(pb)) < 0)

  340.                     return AVERROR(ENOMEM);

  341.             }

  342.             break;

  343.         case MKBETAG('S', 'T', 'V', 'I'):

  344.             if (f_stvi++) {

  345.                 ret = AVERROR(EINVAL);

  346.                 goto fail;

  347.             }

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

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

  350.             if (codec->time_base.num <= 0 || codec->time_base.den <= 0) {

  351.                 av_log(s, AV_LOG_ERROR, "Invalid time base %d/%d\n",

  352.                        codec->time_base.num, codec->time_base.den);

  353.                 ret = AVERROR_INVALIDDATA;

  354.                 goto fail;

  355.             }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  398.             break;

  399.         case MKBETAG('S', 'T', 'A', 'U'):

  400.             if (f_stau++) {

  401.                 ret = AVERROR(EINVAL);

  402.                 goto fail;

  403.             }

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

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

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

  407.             break;

  408.         case MKBETAG('C', 'P', 'R', 'V'):

  409.             if (f_cprv++) {

  410.                 ret = AVERROR(EINVAL);

  411.                 goto fail;

  412.             }

  413.             enc = avcodec_find_encoder(codec->codec_id);

  414.             if (enc && enc->priv_data_size && enc->priv_class) {

  415.                 buffer = av_malloc(size + 1);

  416.                 if (!buffer) {

  417.                     ret = AVERROR(ENOMEM);

  418.                     goto fail;

  419.                 }

  420.                 avio_get_str(pb, size, buffer, size + 1);

  421.                 if ((ret = ffm_append_recommended_configuration(st, &buffer)) < 0)

  422.                     goto fail;

  423.             }

  424.             break;

  425.         case MKBETAG('S', '2', 'V', 'I'):

  426.             if (f_stvi++ || !size) {

  427.                 ret = AVERROR(EINVAL);

  428.                 goto fail;

  429.             }

  430.             buffer = av_malloc(size);

  431.             if (!buffer) {

  432.                 ret = AVERROR(ENOMEM);

  433.                 goto fail;

  434.             }

  435.             avio_get_str(pb, INT_MAX, buffer, size);

  436.             av_set_options_string(codec, buffer, "=", ",");

  437.             if ((ret = ffm_append_recommended_configuration(st, &buffer)) < 0)

  438.                 goto fail;

  439.             break;

  440.         case MKBETAG('S', '2', 'A', 'U'):

  441.             if (f_stau++ || !size) {

  442.                 ret = AVERROR(EINVAL);

  443.                 goto fail;

  444.             }

  445.             buffer = av_malloc(size);

  446.             if (!buffer) {

  447.                 ret = AVERROR(ENOMEM);

  448.                 goto fail;

  449.             }

  450.             avio_get_str(pb, INT_MAX, buffer, size);

  451.             av_set_options_string(codec, buffer, "=", ",");

  452.             if ((ret = ffm_append_recommended_configuration(st, &buffer)) < 0)

  453.                 goto fail;

  454.             break;

  455.         }

  456.         avio_seek(pb, next, SEEK_SET);

  457.     }

  458. 

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

  460.     while ((avio_tell(pb) % ffm->packet_size) != 0 && !pb->eof_reached)

  461.         avio_r8(pb);

  462. 

  463.     /* init packet demux */

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

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

  466.     ffm->frame_offset = 0;

  467.     ffm->dts = 0;

  468.     ffm->read_state = READ_HEADER;

  469.     ffm->first_packet = 1;

  470.     return 0;

  471.  fail:

  472.     ffm_close(s);

  473.     return ret;

  474. }

  475. 

  476. static int ffm_read_header(AVFormatContext *s)

  477. {

  478.     FFMContext *ffm = s->priv_data;

  479.     AVStream *st;

  480.     AVIOContext *pb = s->pb;

  481.     AVCodecContext *codec;

  482.     int i, nb_streams;

  483.     uint32_t tag;

  484. 

  485.     /* header */

  486.     tag = avio_rl32(pb);

  487.     if (tag == MKTAG('F', 'F', 'M', '2'))

  488.         return ffm2_read_header(s);

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

  490.         goto fail;

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

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

  493.         goto fail;

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

  495.     /* get also filesize */

  496.     if (pb->seekable) {

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

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

  499.             adjust_write_index(s);

  500.     } else {

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

  502.     }

  503. 

  504.     nb_streams = avio_rb32(pb);

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

  506.     /* read each stream */

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

  508.         char rc_eq_buf[128];

  509. 

  510.         st = avformat_new_stream(s, NULL);

  511.         if (!st)

  512.             goto fail;

  513. 

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

  515. 

  516.         codec = st->codec;

  517.         /* generic info */

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

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

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

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

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

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

  524.         /* specific info */

  525.         switch(codec->codec_type) {

  526.         case AVMEDIA_TYPE_VIDEO:

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

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

  529.             if (codec->time_base.num <= 0 || codec->time_base.den <= 0) {

  530.                 av_log(s, AV_LOG_ERROR, "Invalid time base %d/%d\n",

  531.                        codec->time_base.num, codec->time_base.den);

  532.                 goto fail;

  533.             }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  576.             break;

  577.         case AVMEDIA_TYPE_AUDIO:

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

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

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

  581.             break;

  582.         default:

  583.             goto fail;

  584.         }

  585.         if (codec->flags & AV_CODEC_FLAG_GLOBAL_HEADER) {

  586.             if (ff_get_extradata(codec, pb, avio_rb32(pb)) < 0)

  587.                 return AVERROR(ENOMEM);

  588.         }

  589.     }

  590. 

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

  592.     while ((avio_tell(pb) % ffm->packet_size) != 0 && !pb->eof_reached)

  593.         avio_r8(pb);

  594. 

  595.     /* init packet demux */

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

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

  598.     ffm->frame_offset = 0;

  599.     ffm->dts = 0;

  600.     ffm->read_state = READ_HEADER;

  601.     ffm->first_packet = 1;

  602.     return 0;

  603.  fail:

  604.     ffm_close(s);

  605.     return -1;

  606. }

  607. 

  608. /* return < 0 if eof */

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

  610. {

  611.     int size;

  612.     FFMContext *ffm = s->priv_data;

  613.     int duration, ret;

  614. 

  615.     switch(ffm->read_state) {

  616.     case READ_HEADER:

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

  618.             return ret;

  619. 

  620.         ff_dlog(s, "pos=%08"PRIx64" spos=%"PRIx64", write_index=%"PRIx64" size=%"PRIx64"\n",

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

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

  623.             FRAME_HEADER_SIZE)

  624.             return -1;

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

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

  627.                 return -1;

  628.         ffm->read_state = READ_DATA;

  629.         /* fall through */

  630.     case READ_DATA:

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

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

  633.             return ret;

  634. 

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

  636. 

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

  638.             return AVERROR(ENOMEM);

  639.         }

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

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

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

  643.             av_packet_unref(pkt);

  644.             ffm->read_state = READ_HEADER;

  645.             return -1;

  646.         }

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

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

  649.             pkt->flags |= AV_PKT_FLAG_KEY;

  650. 

  651.         ffm->read_state = READ_HEADER;

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

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

  654.             av_packet_unref(pkt);

  655.             return -1;

  656.         }

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

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

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

  660.         else

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

  662.         pkt->duration = duration;

  663.         break;

  664.     }

  665.     return 0;

  666. }

  667. 

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

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

  670.    approximative */

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

  672. {

  673.     FFMContext *ffm = s->priv_data;

  674.     int64_t pos_min, pos_max, pos;

  675.     int64_t pts_min, pts_max, pts;

  676.     double pos1;

  677. 

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

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

  680.        dichotomy in typical cases) */

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

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

  683.             pos_min = FFM_PACKET_SIZE;

  684.             pos_max = ffm->write_index - FFM_PACKET_SIZE;

  685.         } else {

  686.             pos_min = ffm->write_index;

  687.             pos_max = ffm->file_size - FFM_PACKET_SIZE;

  688.         }

  689.     } else {

  690.         pos_min = FFM_PACKET_SIZE;

  691.         pos_max = ffm->file_size - FFM_PACKET_SIZE;

  692.     }

  693.     while (pos_min <= pos_max) {

  694.         pts_min = get_dts(s, pos_min);

  695.         pts_max = get_dts(s, pos_max);

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

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

  698.             goto found;

  699.         }

  700.         /* linear interpolation */

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

  702.             (double)(pts_max - pts_min);

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

  704.         if (pos <= pos_min)

  705.             pos = pos_min;

  706.         else if (pos >= pos_max)

  707.             pos = pos_max;

  708.         pts = get_dts(s, pos);

  709.         /* check if we are lucky */

  710.         if (pts == wanted_pts) {

  711.             goto found;

  712.         } else if (pts > wanted_pts) {

  713.             pos_max = pos - FFM_PACKET_SIZE;

  714.         } else {

  715.             pos_min = pos + FFM_PACKET_SIZE;

  716.         }

  717.     }

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

  719. 

  720.  found:

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

  722.         return -1;

  723. 

  724.     /* reset read state */

  725.     ffm->read_state = READ_HEADER;

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

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

  728.     ffm->first_packet = 1;

  729. 

  730.     return 0;

  731. }

  732. 

  733. static int ffm_probe(AVProbeData *p)

  734. {

  735.     if (

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

  737.         (p->buf[3] == '1' || p->buf[3] == '2'))

  738.         return AVPROBE_SCORE_MAX + 1;

  739.     return 0;

  740. }

  741. 

  742. static const AVOption options[] = {

  743.     {"server_attached", NULL, offsetof(FFMContext, server_attached), AV_OPT_TYPE_BOOL, {.i64 = 0}, 0, 1, AV_OPT_FLAG_EXPORT },

  744.     {"ffm_write_index", NULL, offsetof(FFMContext, write_index), AV_OPT_TYPE_INT64, {.i64 = 0}, 0, 1, AV_OPT_FLAG_EXPORT },

  745.     {"ffm_file_size", NULL, offsetof(FFMContext, file_size), AV_OPT_TYPE_INT64, {.i64 = 0}, 0, 1, AV_OPT_FLAG_EXPORT },

  746.     { NULL },

  747. };

  748. 

  749. static const AVClass ffm_class = {

  750.     .class_name = "ffm demuxer",

  751.     .item_name  = av_default_item_name,

  752.     .option     = options,

  753.     .version    = LIBAVUTIL_VERSION_INT,

  754. };

  755. AVInputFormat ff_ffm_demuxer = {

  756.     .name           = "ffm",

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

  758.     .priv_data_size = sizeof(FFMContext),

  759.     .read_probe     = ffm_probe,

  760.     .read_header    = ffm_read_header,

  761.     .read_packet    = ffm_read_packet,

  762.     .read_close     = ffm_close,

  763.     .read_seek      = ffm_seek,

  764.     .priv_class     = &ffm_class,

  765. };