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

  104.     retry_read:

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

  106.                 int64_t tell = avio_tell(pb);

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

  108.                 if (ret < 0)

  109.                     return ret;

  110.                 avio_seek(pb, tell, SEEK_SET);

  111.             }

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

  113.             if (id != PACKET_ID) {

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

  115.                     return -1;

  116.                 last_pos = avio_tell(pb);

  117.             }

  118.             fill_size = avio_rb16(pb);

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

  120.             frame_offset = avio_rb16(pb);

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

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

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

  124.                 return -1;

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

  126.                handle it specifically */

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

  128.                 if (!frame_offset) {

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

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

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

  132.                         seekback = FFMAX(seekback, 0);

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

  134.                         goto retry_read;

  135.                     }

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

  137.                     return 0;

  138.                 }

  139.                 ffm->first_packet = 0;

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

  141.                     return -1;

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

  143.                 if (!header)

  144.                     break;

  145.             } else {

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

  147.             }

  148.             goto redo;

  149.         }

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

  151.         buf += len;

  152.         ffm->packet_ptr += len;

  153.         size -= len;

  154.         header = 0;

  155.     }

  156.     return size1 - size;

  157. }

  158. 

  159. /* ensure that actual seeking happens between FFM_PACKET_SIZE

  160.    and file_size - FFM_PACKET_SIZE */

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

  162. {

  163.     FFMContext *ffm = s->priv_data;

  164.     AVIOContext *pb = s->pb;

  165.     int64_t pos;

  166. 

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

  168.     pos = FFMAX(pos, FFM_PACKET_SIZE);

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

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

  171. }

  172. 

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

  174. {

  175.     AVIOContext *pb = s->pb;

  176.     int64_t dts;

  177. 

  178.     ffm_seek1(s, pos);

  179.     avio_skip(pb, 4);

  180.     dts = avio_rb64(pb);

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

  182.     return dts;

  183. }

  184. 

  185. static void adjust_write_index(AVFormatContext *s)

  186. {

  187.     FFMContext *ffm = s->priv_data;

  188.     AVIOContext *pb = s->pb;

  189.     int64_t pts;

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

  191.     int64_t pos_min, pos_max;

  192.     int64_t pts_start;

  193.     int64_t ptr = avio_tell(pb);

  194. 

  195. 

  196.     pos_min = 0;

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

  198. 

  199.     pts_start = get_dts(s, pos_min);

  200. 

  201.     pts = get_dts(s, pos_max);

  202. 

  203.     if (pts - 100000 > pts_start)

  204.         goto end;

  205. 

  206.     ffm->write_index = FFM_PACKET_SIZE;

  207. 

  208.     pts_start = get_dts(s, pos_min);

  209. 

  210.     pts = get_dts(s, pos_max);

  211. 

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

  213.         while (1) {

  214.             int64_t newpos;

  215.             int64_t newpts;

  216. 

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

  218. 

  219.             if (newpos == pos_min)

  220.                 break;

  221. 

  222.             newpts = get_dts(s, newpos);

  223. 

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

  225.                 pos_max = newpos;

  226.                 pts = newpts;

  227.             } else {

  228.                 pos_min = newpos;

  229.             }

  230.         }

  231.         ffm->write_index += pos_max;

  232.     }

  233. 

  234.  end:

  235.     avio_seek(pb, ptr, SEEK_SET);

  236. }

  237. 

  238. 

  239. static int ffm_close(AVFormatContext *s)

  240. {

  241.     int i;

  242. 

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

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

  245. 

  246.     return 0;

  247. }

  248. 

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

  250. {

  251.     int ret;

  252.     size_t newsize;

  253.     av_assert0(conf && st);

  254.     if (!*conf)

  255.         return 0;

  256.     if (!st->recommended_encoder_configuration) {

  257.         st->recommended_encoder_configuration = *conf;

  258.         *conf = 0;

  259.         return 0;

  260.     }

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

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

  263.         return ret;

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

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

  266.     av_freep(conf);

  267.     return 0;

  268. }

  269. 

  270. static int ffm2_read_header(AVFormatContext *s)

  271. {

  272.     FFMContext *ffm = s->priv_data;

  273.     AVStream *st;

  274.     AVIOContext *pb = s->pb;

  275.     AVCodecContext *codec;

  276.     int ret;

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

  278.     AVCodec *enc;

  279.     char *buffer;

  280. 

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

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

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

  284.                ffm->packet_size, FFM_PACKET_SIZE);

  285.         ret = AVERROR_INVALIDDATA;

  286.         goto fail;

  287.     }

  288. 

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

  290.     /* get also filesize */

  291.     if (pb->seekable) {

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

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

  294.             adjust_write_index(s);

  295.     } else {

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

  297.     }

  298. 

  299.     while(!avio_feof(pb)) {

  300.         unsigned id = avio_rb32(pb);

  301.         unsigned size = avio_rb32(pb);

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

  303.         char rc_eq_buf[128];

  304. 

  305.         if(!id)

  306.             break;

  307. 

  308.         switch(id) {

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

  310.             if (f_main++) {

  311.                 ret = AVERROR(EINVAL);

  312.                 goto fail;

  313.             }

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

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

  316.             break;

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

  318.             f_cprv = f_stvi = f_stau = 0;

  319.             st = avformat_new_stream(s, NULL);

  320.             if (!st) {

  321.                 ret = AVERROR(ENOMEM);

  322.                 goto fail;

  323.             }

  324. 

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

  326. 

  327.             codec = st->codec;

  328.             /* generic info */

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

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

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

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

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

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

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

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

  337.                     return AVERROR(ENOMEM);

  338.             }

  339.             break;

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

  341.             if (f_stvi++) {

  342.                 ret = AVERROR(EINVAL);

  343.                 goto fail;

  344.             }

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

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

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

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

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

  350.                 ret = AVERROR_INVALIDDATA;

  351.                 goto fail;

  352.             }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  395.             break;

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

  397.             if (f_stau++) {

  398.                 ret = AVERROR(EINVAL);

  399.                 goto fail;

  400.             }

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

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

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

  404.             break;

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

  406.             if (f_cprv++) {

  407.                 ret = AVERROR(EINVAL);

  408.                 goto fail;

  409.             }

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

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

  412.                 buffer = av_malloc(size + 1);

  413.                 if (!buffer) {

  414.                     ret = AVERROR(ENOMEM);

  415.                     goto fail;

  416.                 }

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

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

  419.                     goto fail;

  420.             }

  421.             break;

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

  423.             if (f_stvi++) {

  424.                 ret = AVERROR(EINVAL);

  425.                 goto fail;

  426.             }

  427.             buffer = av_malloc(size);

  428.             if (!buffer) {

  429.                 ret = AVERROR(ENOMEM);

  430.                 goto fail;

  431.             }

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

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

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

  435.                 goto fail;

  436.             break;

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

  438.             if (f_stau++) {

  439.                 ret = AVERROR(EINVAL);

  440.                 goto fail;

  441.             }

  442.             buffer = av_malloc(size);

  443.             if (!buffer) {

  444.                 ret = AVERROR(ENOMEM);

  445.                 goto fail;

  446.             }

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

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

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

  450.                 goto fail;

  451.             break;

  452.         }

  453.         avio_seek(pb, next, SEEK_SET);

  454.     }

  455. 

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

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

  458.         avio_r8(pb);

  459. 

  460.     /* init packet demux */

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

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

  463.     ffm->frame_offset = 0;

  464.     ffm->dts = 0;

  465.     ffm->read_state = READ_HEADER;

  466.     ffm->first_packet = 1;

  467.     return 0;

  468.  fail:

  469.     ffm_close(s);

  470.     return ret;

  471. }

  472. 

  473. static int ffm_read_header(AVFormatContext *s)

  474. {

  475.     FFMContext *ffm = s->priv_data;

  476.     AVStream *st;

  477.     AVIOContext *pb = s->pb;

  478.     AVCodecContext *codec;

  479.     int i, nb_streams;

  480.     uint32_t tag;

  481. 

  482.     /* header */

  483.     tag = avio_rl32(pb);

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

  485.         return ffm2_read_header(s);

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

  487.         goto fail;

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

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

  490.         goto fail;

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

  492.     /* get also filesize */

  493.     if (pb->seekable) {

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

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

  496.             adjust_write_index(s);

  497.     } else {

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

  499.     }

  500. 

  501.     nb_streams = avio_rb32(pb);

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

  503.     /* read each stream */

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

  505.         char rc_eq_buf[128];

  506. 

  507.         st = avformat_new_stream(s, NULL);

  508.         if (!st)

  509.             goto fail;

  510. 

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

  512. 

  513.         codec = st->codec;

  514.         /* generic info */

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

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

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

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

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

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

  521.         /* specific info */

  522.         switch(codec->codec_type) {

  523.         case AVMEDIA_TYPE_VIDEO:

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

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

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

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

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

  529.                 goto fail;

  530.             }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  573.             break;

  574.         case AVMEDIA_TYPE_AUDIO:

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

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

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

  578.             break;

  579.         default:

  580.             goto fail;

  581.         }

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

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

  584.                 return AVERROR(ENOMEM);

  585.         }

  586.     }

  587. 

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

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

  590.         avio_r8(pb);

  591. 

  592.     /* init packet demux */

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

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

  595.     ffm->frame_offset = 0;

  596.     ffm->dts = 0;

  597.     ffm->read_state = READ_HEADER;

  598.     ffm->first_packet = 1;

  599.     return 0;

  600.  fail:

  601.     ffm_close(s);

  602.     return -1;

  603. }

  604. 

  605. /* return < 0 if eof */

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

  607. {

  608.     int size;

  609.     FFMContext *ffm = s->priv_data;

  610.     int duration, ret;

  611. 

  612.     switch(ffm->read_state) {

  613.     case READ_HEADER:

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

  615.             return ret;

  616. 

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

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

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

  620.             FRAME_HEADER_SIZE)

  621.             return -1;

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

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

  624.                 return -1;

  625.         ffm->read_state = READ_DATA;

  626.         /* fall through */

  627.     case READ_DATA:

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

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

  630.             return ret;

  631. 

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

  633. 

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

  635.             return AVERROR(ENOMEM);

  636.         }

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

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

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

  640.             av_packet_unref(pkt);

  641.             ffm->read_state = READ_HEADER;

  642.             return -1;

  643.         }

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

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

  646.             pkt->flags |= AV_PKT_FLAG_KEY;

  647. 

  648.         ffm->read_state = READ_HEADER;

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

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

  651.             av_packet_unref(pkt);

  652.             return -1;

  653.         }

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

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

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

  657.         else

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

  659.         pkt->duration = duration;

  660.         break;

  661.     }

  662.     return 0;

  663. }

  664. 

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

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

  667.    approximative */

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

  669. {

  670.     FFMContext *ffm = s->priv_data;

  671.     int64_t pos_min, pos_max, pos;

  672.     int64_t pts_min, pts_max, pts;

  673.     double pos1;

  674. 

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

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

  677.        dichotomy in typical cases) */

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

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

  680.             pos_min = FFM_PACKET_SIZE;

  681.             pos_max = ffm->write_index - FFM_PACKET_SIZE;

  682.         } else {

  683.             pos_min = ffm->write_index;

  684.             pos_max = ffm->file_size - FFM_PACKET_SIZE;

  685.         }

  686.     } else {

  687.         pos_min = FFM_PACKET_SIZE;

  688.         pos_max = ffm->file_size - FFM_PACKET_SIZE;

  689.     }

  690.     while (pos_min <= pos_max) {

  691.         pts_min = get_dts(s, pos_min);

  692.         pts_max = get_dts(s, pos_max);

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

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

  695.             goto found;

  696.         }

  697.         /* linear interpolation */

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

  699.             (double)(pts_max - pts_min);

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

  701.         if (pos <= pos_min)

  702.             pos = pos_min;

  703.         else if (pos >= pos_max)

  704.             pos = pos_max;

  705.         pts = get_dts(s, pos);

  706.         /* check if we are lucky */

  707.         if (pts == wanted_pts) {

  708.             goto found;

  709.         } else if (pts > wanted_pts) {

  710.             pos_max = pos - FFM_PACKET_SIZE;

  711.         } else {

  712.             pos_min = pos + FFM_PACKET_SIZE;

  713.         }

  714.     }

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

  716. 

  717.  found:

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

  719.         return -1;

  720. 

  721.     /* reset read state */

  722.     ffm->read_state = READ_HEADER;

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

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

  725.     ffm->first_packet = 1;

  726. 

  727.     return 0;

  728. }

  729. 

  730. static int ffm_probe(AVProbeData *p)

  731. {

  732.     if (

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

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

  735.         return AVPROBE_SCORE_MAX + 1;

  736.     return 0;

  737. }

  738. 

  739. static const AVOption options[] = {

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

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

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

  743.     { NULL },

  744. };

  745. 

  746. static const AVClass ffm_class = {

  747.     .class_name = "ffm demuxer",

  748.     .item_name  = av_default_item_name,

  749.     .option     = options,

  750.     .version    = LIBAVUTIL_VERSION_INT,

  751. };

  752. AVInputFormat ff_ffm_demuxer = {

  753.     .name           = "ffm",

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

  755.     .priv_data_size = sizeof(FFMContext),

  756.     .read_probe     = ffm_probe,

  757.     .read_header    = ffm_read_header,

  758.     .read_packet    = ffm_read_packet,

  759.     .read_close     = ffm_close,

  760.     .read_seek      = ffm_seek,

  761.     .priv_class     = &ffm_class,

  762. };