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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/intreadwrite.h"

  25. #include "libavutil/intfloat.h"

  26. #include "libavutil/opt.h"

  27. #include "libavutil/avassert.h"

  28. #include "libavutil/avstring.h"

  29. #include "avformat.h"

  30. #include "internal.h"

  31. #include "ffm.h"

  32. #include "avio_internal.h"

  33. 

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

  35. {

  36.     FFMContext *ffm = s->priv_data;

  37.     int64_t pos, avail_size;

  38.     int len;

  39. 

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

  41.     if (size <= len)

  42.         return 1;

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

  44.     if (!ffm->write_index) {

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

  46.             return AVERROR_EOF;

  47.         avail_size = ffm->file_size - pos;

  48.     } else {

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

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

  51.         return AVERROR(EAGAIN);

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

  53.         avail_size = ffm->write_index - pos;

  54.     } else {

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

  56.     }

  57.     }

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

  59.     if (size <= avail_size)

  60.         return 1;

  61.     else

  62.         return AVERROR(EAGAIN);

  63. }

  64. 

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

  66. {

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

  68.     while (state != PACKET_ID) {

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

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

  71.             return -1;

  72.         }

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

  74.     }

  75.     return 0;

  76. }

  77. 

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

  79. static int ffm_read_data(AVFormatContext *s,

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

  81. {

  82.     FFMContext *ffm = s->priv_data;

  83.     AVIOContext *pb = s->pb;

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

  85.     int64_t last_pos = -1;

  86. 

  87.     size1 = size;

  88.     while (size > 0) {

  89.     redo:

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

  91.         if (len < 0)

  92.             return -1;

  93.         if (len > size)

  94.             len = size;

  95.         if (len == 0) {

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

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

  98.     retry_read:

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

  100.                 int64_t tell = avio_tell(pb);

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

  102.                 avio_seek(pb, tell, SEEK_SET);

  103.             }

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

  105.             if (id != PACKET_ID) {

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

  107.                     return -1;

  108.                 last_pos = avio_tell(pb);

  109.             }

  110.             fill_size = avio_rb16(pb);

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

  112.             frame_offset = avio_rb16(pb);

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

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

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

  116.                 return -1;

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

  118.                handle it specifically */

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

  120.                 if (!frame_offset) {

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

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

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

  124.                         seekback = FFMAX(seekback, 0);

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

  126.                         goto retry_read;

  127.                     }

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

  129.                     return 0;

  130.                 }

  131.                 ffm->first_packet = 0;

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

  133.                     return -1;

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

  135.                 if (!header)

  136.                     break;

  137.             } else {

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

  139.             }

  140.             goto redo;

  141.         }

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

  143.         buf += len;

  144.         ffm->packet_ptr += len;

  145.         size -= len;

  146.         header = 0;

  147.     }

  148.     return size1 - size;

  149. }

  150. 

  151. /* ensure that acutal seeking happens between FFM_PACKET_SIZE

  152.    and file_size - FFM_PACKET_SIZE */

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

  154. {

  155.     FFMContext *ffm = s->priv_data;

  156.     AVIOContext *pb = s->pb;

  157.     int64_t pos;

  158. 

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

  160.     pos = FFMAX(pos, FFM_PACKET_SIZE);

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

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

  163. }

  164. 

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

  166. {

  167.     AVIOContext *pb = s->pb;

  168.     int64_t dts;

  169. 

  170.     ffm_seek1(s, pos);

  171.     avio_skip(pb, 4);

  172.     dts = avio_rb64(pb);

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

  174.     return dts;

  175. }

  176. 

  177. static void adjust_write_index(AVFormatContext *s)

  178. {

  179.     FFMContext *ffm = s->priv_data;

  180.     AVIOContext *pb = s->pb;

  181.     int64_t pts;

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

  183.     int64_t pos_min, pos_max;

  184.     int64_t pts_start;

  185.     int64_t ptr = avio_tell(pb);

  186. 

  187. 

  188.     pos_min = 0;

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

  190. 

  191.     pts_start = get_dts(s, pos_min);

  192. 

  193.     pts = get_dts(s, pos_max);

  194. 

  195.     if (pts - 100000 > pts_start)

  196.         goto end;

  197. 

  198.     ffm->write_index = FFM_PACKET_SIZE;

  199. 

  200.     pts_start = get_dts(s, pos_min);

  201. 

  202.     pts = get_dts(s, pos_max);

  203. 

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

  205.         while (1) {

  206.             int64_t newpos;

  207.             int64_t newpts;

  208. 

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

  210. 

  211.             if (newpos == pos_min)

  212.                 break;

  213. 

  214.             newpts = get_dts(s, newpos);

  215. 

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

  217.                 pos_max = newpos;

  218.                 pts = newpts;

  219.             } else {

  220.                 pos_min = newpos;

  221.             }

  222.         }

  223.         ffm->write_index += pos_max;

  224.     }

  225. 

  226.  end:

  227.     avio_seek(pb, ptr, SEEK_SET);

  228. }

  229. 

  230. 

  231. static int ffm_close(AVFormatContext *s)

  232. {

  233.     int i;

  234. 

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

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

  237. 

  238.     return 0;

  239. }

  240. 

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

  242. {

  243.     int ret;

  244.     size_t newsize;

  245.     av_assert0(conf && st);

  246.     if (!*conf)

  247.         return 0;

  248.     if (!st->recommended_encoder_configuration) {

  249.         st->recommended_encoder_configuration = *conf;

  250.         *conf = 0;

  251.         return 0;

  252.     }

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

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

  255.         return ret;

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

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

  258.     av_freep(conf);

  259.     return 0;

  260. }

  261. 

  262. static int ffm2_read_header(AVFormatContext *s)

  263. {

  264.     FFMContext *ffm = s->priv_data;

  265.     AVStream *st;

  266.     AVIOContext *pb = s->pb;

  267.     AVCodecContext *codec;

  268.     int ret;

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

  270.     AVCodec *enc;

  271.     char *buffer;

  272. 

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

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

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

  276.                ffm->packet_size, FFM_PACKET_SIZE);

  277.         ret = AVERROR_INVALIDDATA;

  278.         goto fail;

  279.     }

  280. 

  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.     while(!avio_feof(pb)) {

  292.         unsigned id = avio_rb32(pb);

  293.         unsigned size = avio_rb32(pb);

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

  295.         char rc_eq_buf[128];

  296. 

  297.         if(!id)

  298.             break;

  299. 

  300.         switch(id) {

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

  302.             if (f_main++) {

  303.                 ret = AVERROR(EINVAL);

  304.                 goto fail;

  305.             }

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

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

  308.             break;

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

  310.             f_cprv = f_stvi = f_stau = 0;

  311.             st = avformat_new_stream(s, NULL);

  312.             if (!st) {

  313.                 ret = AVERROR(ENOMEM);

  314.                 goto fail;

  315.             }

  316. 

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

  318. 

  319.             codec = st->codec;

  320.             /* generic info */

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

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

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

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

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

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

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

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

  329.                     return AVERROR(ENOMEM);

  330.             }

  331.             break;

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

  333.             if (f_stvi++) {

  334.                 ret = AVERROR(EINVAL);

  335.                 goto fail;

  336.             }

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

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

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

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

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

  342.                 ret = AVERROR_INVALIDDATA;

  343.                 goto fail;

  344.             }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  387.             break;

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

  389.             if (f_stau++) {

  390.                 ret = AVERROR(EINVAL);

  391.                 goto fail;

  392.             }

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

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

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

  396.             break;

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

  398.             if (f_cprv++) {

  399.                 ret = AVERROR(EINVAL);

  400.                 goto fail;

  401.             }

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

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

  404.                 buffer = av_malloc(size + 1);

  405.                 if (!buffer) {

  406.                     ret = AVERROR(ENOMEM);

  407.                     goto fail;

  408.                 }

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

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

  411.                     goto fail;

  412.             }

  413.             break;

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

  415.             if (f_stvi++) {

  416.                 ret = AVERROR(EINVAL);

  417.                 goto fail;

  418.             }

  419.             buffer = av_malloc(size);

  420.             if (!buffer) {

  421.                 ret = AVERROR(ENOMEM);

  422.                 goto fail;

  423.             }

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

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

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

  427.                 goto fail;

  428.             break;

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

  430.             if (f_stau++) {

  431.                 ret = AVERROR(EINVAL);

  432.                 goto fail;

  433.             }

  434.             buffer = av_malloc(size);

  435.             if (!buffer) {

  436.                 ret = AVERROR(ENOMEM);

  437.                 goto fail;

  438.             }

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

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

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

  442.                 goto fail;

  443.             break;

  444.         }

  445.         avio_seek(pb, next, SEEK_SET);

  446.     }

  447. 

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

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

  450.         avio_r8(pb);

  451. 

  452.     /* init packet demux */

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

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

  455.     ffm->frame_offset = 0;

  456.     ffm->dts = 0;

  457.     ffm->read_state = READ_HEADER;

  458.     ffm->first_packet = 1;

  459.     return 0;

  460.  fail:

  461.     ffm_close(s);

  462.     return ret;

  463. }

  464. 

  465. static int ffm_read_header(AVFormatContext *s)

  466. {

  467.     FFMContext *ffm = s->priv_data;

  468.     AVStream *st;

  469.     AVIOContext *pb = s->pb;

  470.     AVCodecContext *codec;

  471.     int i, nb_streams;

  472.     uint32_t tag;

  473. 

  474.     /* header */

  475.     tag = avio_rl32(pb);

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

  477.         return ffm2_read_header(s);

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

  479.         goto fail;

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

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

  482.         goto fail;

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

  484.     /* get also filesize */

  485.     if (pb->seekable) {

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

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

  488.             adjust_write_index(s);

  489.     } else {

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

  491.     }

  492. 

  493.     nb_streams = avio_rb32(pb);

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

  495.     /* read each stream */

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

  497.         char rc_eq_buf[128];

  498. 

  499.         st = avformat_new_stream(s, NULL);

  500.         if (!st)

  501.             goto fail;

  502. 

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

  504. 

  505.         codec = st->codec;

  506.         /* generic info */

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

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

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

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

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

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

  513.         /* specific info */

  514.         switch(codec->codec_type) {

  515.         case AVMEDIA_TYPE_VIDEO:

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

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

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

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

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

  521.                 goto fail;

  522.             }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  565.             break;

  566.         case AVMEDIA_TYPE_AUDIO:

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

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

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

  570.             break;

  571.         default:

  572.             goto fail;

  573.         }

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

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

  576.                 return AVERROR(ENOMEM);

  577.         }

  578.     }

  579. 

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

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

  582.         avio_r8(pb);

  583. 

  584.     /* init packet demux */

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

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

  587.     ffm->frame_offset = 0;

  588.     ffm->dts = 0;

  589.     ffm->read_state = READ_HEADER;

  590.     ffm->first_packet = 1;

  591.     return 0;

  592.  fail:

  593.     ffm_close(s);

  594.     return -1;

  595. }

  596. 

  597. /* return < 0 if eof */

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

  599. {

  600.     int size;

  601.     FFMContext *ffm = s->priv_data;

  602.     int duration, ret;

  603. 

  604.     switch(ffm->read_state) {

  605.     case READ_HEADER:

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

  607.             return ret;

  608. 

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

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

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

  612.             FRAME_HEADER_SIZE)

  613.             return -1;

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

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

  616.                 return -1;

  617.         ffm->read_state = READ_DATA;

  618.         /* fall through */

  619.     case READ_DATA:

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

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

  622.             return ret;

  623. 

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

  625. 

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

  627.             return AVERROR(ENOMEM);

  628.         }

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

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

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

  632.             av_free_packet(pkt);

  633.             ffm->read_state = READ_HEADER;

  634.             return -1;

  635.         }

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

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

  638.             pkt->flags |= AV_PKT_FLAG_KEY;

  639. 

  640.         ffm->read_state = READ_HEADER;

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

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

  643.             av_free_packet(pkt);

  644.             return -1;

  645.         }

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

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

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

  649.         else

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

  651.         pkt->duration = duration;

  652.         break;

  653.     }

  654.     return 0;

  655. }

  656. 

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

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

  659.    approximative */

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

  661. {

  662.     FFMContext *ffm = s->priv_data;

  663.     int64_t pos_min, pos_max, pos;

  664.     int64_t pts_min, pts_max, pts;

  665.     double pos1;

  666. 

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

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

  669.        dichotomy in typical cases) */

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

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

  672.             pos_min = FFM_PACKET_SIZE;

  673.             pos_max = ffm->write_index - FFM_PACKET_SIZE;

  674.         } else {

  675.             pos_min = ffm->write_index;

  676.             pos_max = ffm->file_size - FFM_PACKET_SIZE;

  677.         }

  678.     } else {

  679.         pos_min = FFM_PACKET_SIZE;

  680.         pos_max = ffm->file_size - FFM_PACKET_SIZE;

  681.     }

  682.     while (pos_min <= pos_max) {

  683.         pts_min = get_dts(s, pos_min);

  684.         pts_max = get_dts(s, pos_max);

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

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

  687.             goto found;

  688.         }

  689.         /* linear interpolation */

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

  691.             (double)(pts_max - pts_min);

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

  693.         if (pos <= pos_min)

  694.             pos = pos_min;

  695.         else if (pos >= pos_max)

  696.             pos = pos_max;

  697.         pts = get_dts(s, pos);

  698.         /* check if we are lucky */

  699.         if (pts == wanted_pts) {

  700.             goto found;

  701.         } else if (pts > wanted_pts) {

  702.             pos_max = pos - FFM_PACKET_SIZE;

  703.         } else {

  704.             pos_min = pos + FFM_PACKET_SIZE;

  705.         }

  706.     }

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

  708. 

  709.  found:

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

  711.         return -1;

  712. 

  713.     /* reset read state */

  714.     ffm->read_state = READ_HEADER;

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

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

  717.     ffm->first_packet = 1;

  718. 

  719.     return 0;

  720. }

  721. 

  722. static int ffm_probe(AVProbeData *p)

  723. {

  724.     if (

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

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

  727.         return AVPROBE_SCORE_MAX + 1;

  728.     return 0;

  729. }

  730. 

  731. AVInputFormat ff_ffm_demuxer = {

  732.     .name           = "ffm",

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

  734.     .priv_data_size = sizeof(FFMContext),

  735.     .read_probe     = ffm_probe,

  736.     .read_header    = ffm_read_header,

  737.     .read_packet    = ffm_read_packet,

  738.     .read_close     = ffm_close,

  739.     .read_seek      = ffm_seek,

  740. };