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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. 

  86.     size1 = size;

  87.     while (size > 0) {

  88.     redo:

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

  90.         if (len < 0)

  91.             return -1;

  92.         if (len > size)

  93.             len = size;

  94.         if (len == 0) {

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

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

  97.     retry_read:

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

  99.                 int64_t tell = avio_tell(pb);

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

  101.                 avio_seek(pb, tell, SEEK_SET);

  102.             }

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

  104.             if (id != PACKET_ID)

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

  106.                     return -1;

  107.             fill_size = avio_rb16(pb);

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

  109.             frame_offset = avio_rb16(pb);

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

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

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

  113.                 return -1;

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

  115.                handle it specifically */

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

  117.                 if (!frame_offset) {

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

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

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

  121.                         goto retry_read;

  122.                     }

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

  124.                     return 0;

  125.                 }

  126.                 ffm->first_packet = 0;

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

  128.                     return -1;

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

  130.                 if (!header)

  131.                     break;

  132.             } else {

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

  134.             }

  135.             goto redo;

  136.         }

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

  138.         buf += len;

  139.         ffm->packet_ptr += len;

  140.         size -= len;

  141.         header = 0;

  142.     }

  143.     return size1 - size;

  144. }

  145. 

  146. /* ensure that acutal seeking happens between FFM_PACKET_SIZE

  147.    and file_size - FFM_PACKET_SIZE */

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

  149. {

  150.     FFMContext *ffm = s->priv_data;

  151.     AVIOContext *pb = s->pb;

  152.     int64_t pos;

  153. 

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

  155.     pos = FFMAX(pos, FFM_PACKET_SIZE);

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

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

  158. }

  159. 

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

  161. {

  162.     AVIOContext *pb = s->pb;

  163.     int64_t dts;

  164. 

  165.     ffm_seek1(s, pos);

  166.     avio_skip(pb, 4);

  167.     dts = avio_rb64(pb);

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

  169.     return dts;

  170. }

  171. 

  172. static void adjust_write_index(AVFormatContext *s)

  173. {

  174.     FFMContext *ffm = s->priv_data;

  175.     AVIOContext *pb = s->pb;

  176.     int64_t pts;

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

  178.     int64_t pos_min, pos_max;

  179.     int64_t pts_start;

  180.     int64_t ptr = avio_tell(pb);

  181. 

  182. 

  183.     pos_min = 0;

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

  185. 

  186.     pts_start = get_dts(s, pos_min);

  187. 

  188.     pts = get_dts(s, pos_max);

  189. 

  190.     if (pts - 100000 > pts_start)

  191.         goto end;

  192. 

  193.     ffm->write_index = FFM_PACKET_SIZE;

  194. 

  195.     pts_start = get_dts(s, pos_min);

  196. 

  197.     pts = get_dts(s, pos_max);

  198. 

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

  200.         while (1) {

  201.             int64_t newpos;

  202.             int64_t newpts;

  203. 

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

  205. 

  206.             if (newpos == pos_min)

  207.                 break;

  208. 

  209.             newpts = get_dts(s, newpos);

  210. 

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

  212.                 pos_max = newpos;

  213.                 pts = newpts;

  214.             } else {

  215.                 pos_min = newpos;

  216.             }

  217.         }

  218.         ffm->write_index += pos_max;

  219.     }

  220. 

  221.  end:

  222.     avio_seek(pb, ptr, SEEK_SET);

  223. }

  224. 

  225. 

  226. static int ffm_close(AVFormatContext *s)

  227. {

  228.     int i;

  229. 

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

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

  232. 

  233.     return 0;

  234. }

  235. 

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

  237. {

  238.     int ret;

  239.     size_t newsize;

  240.     av_assert0(conf && st);

  241.     if (!*conf)

  242.         return 0;

  243.     if (!st->recommended_encoder_configuration) {

  244.         st->recommended_encoder_configuration = *conf;

  245.         *conf = 0;

  246.         return 0;

  247.     }

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

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

  250.         return ret;

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

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

  253.     av_freep(conf);

  254.     return 0;

  255. }

  256. 

  257. static int ffm2_read_header(AVFormatContext *s)

  258. {

  259.     FFMContext *ffm = s->priv_data;

  260.     AVStream *st;

  261.     AVIOContext *pb = s->pb;

  262.     AVCodecContext *codec;

  263.     int ret;

  264.     int f_main = 0, f_cprv, f_stvi, f_stau;

  265.     AVCodec *enc;

  266.     char *buffer;

  267. 

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

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

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

  271.                ffm->packet_size, FFM_PACKET_SIZE);

  272.         ret = AVERROR_INVALIDDATA;

  273.         goto fail;

  274.     }

  275. 

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

  277.     /* get also filesize */

  278.     if (pb->seekable) {

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

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

  281.             adjust_write_index(s);

  282.     } else {

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

  284.     }

  285. 

  286.     while(!avio_feof(pb)) {

  287.         unsigned id = avio_rb32(pb);

  288.         unsigned size = avio_rb32(pb);

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

  290.         char rc_eq_buf[128];

  291. 

  292.         if(!id)

  293.             break;

  294. 

  295.         switch(id) {

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

  297.             if (f_main++) {

  298.                 ret = AVERROR(EINVAL);

  299.                 goto fail;

  300.             }

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

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

  303.             break;

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

  305.             f_cprv = f_stvi = f_stau = 0;

  306.             st = avformat_new_stream(s, NULL);

  307.             if (!st) {

  308.                 ret = AVERROR(ENOMEM);

  309.                 goto fail;

  310.             }

  311. 

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

  313. 

  314.             codec = st->codec;

  315.             /* generic info */

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

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

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

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

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

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

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

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

  324.                     return AVERROR(ENOMEM);

  325.             }

  326.             break;

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

  328.             if (f_stvi++) {

  329.                 ret = AVERROR(EINVAL);

  330.                 goto fail;

  331.             }

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  376.             break;

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

  378.             if (f_stau++) {

  379.                 ret = AVERROR(EINVAL);

  380.                 goto fail;

  381.             }

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

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

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

  385.             break;

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

  387.             if (f_cprv++) {

  388.                 ret = AVERROR(EINVAL);

  389.                 goto fail;

  390.             }

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

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

  393.                 buffer = av_malloc(size + 1);

  394.                 if (!buffer) {

  395.                     ret = AVERROR(ENOMEM);

  396.                     goto fail;

  397.                 }

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

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

  400.                     goto fail;

  401.             }

  402.             break;

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

  404.             if (f_stvi++) {

  405.                 ret = AVERROR(EINVAL);

  406.                 goto fail;

  407.             }

  408.             buffer = av_malloc(size);

  409.             if (!buffer) {

  410.                 ret = AVERROR(ENOMEM);

  411.                 goto fail;

  412.             }

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

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

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

  416.                 goto fail;

  417.             break;

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

  419.             if (f_stau++) {

  420.                 ret = AVERROR(EINVAL);

  421.                 goto fail;

  422.             }

  423.             buffer = av_malloc(size);

  424.             if (!buffer) {

  425.                 ret = AVERROR(ENOMEM);

  426.                 goto fail;

  427.             }

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

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

  430.             ffm_append_recommended_configuration(st, &buffer);

  431.             break;

  432.         }

  433.         avio_seek(pb, next, SEEK_SET);

  434.     }

  435. 

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

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

  438.         avio_r8(pb);

  439. 

  440.     /* init packet demux */

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

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

  443.     ffm->frame_offset = 0;

  444.     ffm->dts = 0;

  445.     ffm->read_state = READ_HEADER;

  446.     ffm->first_packet = 1;

  447.     return 0;

  448.  fail:

  449.     ffm_close(s);

  450.     return ret;

  451. }

  452. 

  453. static int ffm_read_header(AVFormatContext *s)

  454. {

  455.     FFMContext *ffm = s->priv_data;

  456.     AVStream *st;

  457.     AVIOContext *pb = s->pb;

  458.     AVCodecContext *codec;

  459.     int i, nb_streams;

  460.     uint32_t tag;

  461. 

  462.     /* header */

  463.     tag = avio_rl32(pb);

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

  465.         return ffm2_read_header(s);

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

  467.         goto fail;

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

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

  470.         goto fail;

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

  472.     /* get also filesize */

  473.     if (pb->seekable) {

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

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

  476.             adjust_write_index(s);

  477.     } else {

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

  479.     }

  480. 

  481.     nb_streams = avio_rb32(pb);

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

  483.     /* read each stream */

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

  485.         char rc_eq_buf[128];

  486. 

  487.         st = avformat_new_stream(s, NULL);

  488.         if (!st)

  489.             goto fail;

  490. 

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

  492. 

  493.         codec = st->codec;

  494.         /* generic info */

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

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

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

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

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

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

  501.         /* specific info */

  502.         switch(codec->codec_type) {

  503.         case AVMEDIA_TYPE_VIDEO:

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

  548.             break;

  549.         case AVMEDIA_TYPE_AUDIO:

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

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

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

  553.             break;

  554.         default:

  555.             goto fail;

  556.         }

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

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

  559.                 return AVERROR(ENOMEM);

  560.         }

  561.     }

  562. 

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

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

  565.         avio_r8(pb);

  566. 

  567.     /* init packet demux */

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

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

  570.     ffm->frame_offset = 0;

  571.     ffm->dts = 0;

  572.     ffm->read_state = READ_HEADER;

  573.     ffm->first_packet = 1;

  574.     return 0;

  575.  fail:

  576.     ffm_close(s);

  577.     return -1;

  578. }

  579. 

  580. /* return < 0 if eof */

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

  582. {

  583.     int size;

  584.     FFMContext *ffm = s->priv_data;

  585.     int duration, ret;

  586. 

  587.     switch(ffm->read_state) {

  588.     case READ_HEADER:

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

  590.             return ret;

  591. 

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

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

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

  595.             FRAME_HEADER_SIZE)

  596.             return -1;

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

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

  599.                 return -1;

  600.         ffm->read_state = READ_DATA;

  601.         /* fall through */

  602.     case READ_DATA:

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

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

  605.             return ret;

  606. 

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

  608. 

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

  610.             return AVERROR(ENOMEM);

  611.         }

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

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

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

  615.             av_free_packet(pkt);

  616.             ffm->read_state = READ_HEADER;

  617.             return -1;

  618.         }

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

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

  621.             pkt->flags |= AV_PKT_FLAG_KEY;

  622. 

  623.         ffm->read_state = READ_HEADER;

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

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

  626.             av_free_packet(pkt);

  627.             return -1;

  628.         }

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

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

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

  632.         else

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

  634.         pkt->duration = duration;

  635.         break;

  636.     }

  637.     return 0;

  638. }

  639. 

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

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

  642.    approximative */

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

  644. {

  645.     FFMContext *ffm = s->priv_data;

  646.     int64_t pos_min, pos_max, pos;

  647.     int64_t pts_min, pts_max, pts;

  648.     double pos1;

  649. 

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

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

  652.        dichotomy in typical cases) */

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

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

  655.             pos_min = FFM_PACKET_SIZE;

  656.             pos_max = ffm->write_index - FFM_PACKET_SIZE;

  657.         } else {

  658.             pos_min = ffm->write_index;

  659.             pos_max = ffm->file_size - FFM_PACKET_SIZE;

  660.         }

  661.     } else {

  662.         pos_min = FFM_PACKET_SIZE;

  663.         pos_max = ffm->file_size - FFM_PACKET_SIZE;

  664.     }

  665.     while (pos_min <= pos_max) {

  666.         pts_min = get_dts(s, pos_min);

  667.         pts_max = get_dts(s, pos_max);

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

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

  670.             goto found;

  671.         }

  672.         /* linear interpolation */

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

  674.             (double)(pts_max - pts_min);

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

  676.         if (pos <= pos_min)

  677.             pos = pos_min;

  678.         else if (pos >= pos_max)

  679.             pos = pos_max;

  680.         pts = get_dts(s, pos);

  681.         /* check if we are lucky */

  682.         if (pts == wanted_pts) {

  683.             goto found;

  684.         } else if (pts > wanted_pts) {

  685.             pos_max = pos - FFM_PACKET_SIZE;

  686.         } else {

  687.             pos_min = pos + FFM_PACKET_SIZE;

  688.         }

  689.     }

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

  691. 

  692.  found:

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

  694.         return -1;

  695. 

  696.     /* reset read state */

  697.     ffm->read_state = READ_HEADER;

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

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

  700.     ffm->first_packet = 1;

  701. 

  702.     return 0;

  703. }

  704. 

  705. static int ffm_probe(AVProbeData *p)

  706. {

  707.     if (

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

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

  710.         return AVPROBE_SCORE_MAX + 1;

  711.     return 0;

  712. }

  713. 

  714. AVInputFormat ff_ffm_demuxer = {

  715.     .name           = "ffm",

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

  717.     .priv_data_size = sizeof(FFMContext),

  718.     .read_probe     = ffm_probe,

  719.     .read_header    = ffm_read_header,

  720.     .read_packet    = ffm_read_packet,

  721.     .read_close     = ffm_close,

  722.     .read_seek      = ffm_seek,

  723. };