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  1. /*
  2.  * Live smooth streaming fragmenter
  3.  * Copyright (c) 2012 Martin Storsjo
  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 "config.h"
  23. #include <float.h>
  24. #if HAVE_UNISTD_H
  25. #include <unistd.h>
  26. #endif
  27.  
  28. #include "avformat.h"
  29. #include "internal.h"
  30. #include "os_support.h"
  31. #include "avc.h"
  32. #include "url.h"
  33. #include "isom.h"
  34.  
  35. #include "libavutil/opt.h"
  36. #include "libavutil/avstring.h"
  37. #include "libavutil/mathematics.h"
  38. #include "libavutil/intreadwrite.h"
  39.  
  40. typedef struct {
  41.     char file[1024];
  42.     char infofile[1024];
  43.     int64_t start_time, duration;
  44.     int n;
  45.     int64_t start_pos, size;
  46. } Fragment;
  47.  
  48. typedef struct {
  49.     AVFormatContext *ctx;
  50.     int ctx_inited;
  51.     char dirname[1024];
  52.     uint8_t iobuf[32768];
  53.     URLContext *out;  // Current output stream where all output is written
  54.     URLContext *out2; // Auxiliary output stream where all output is also written
  55.     URLContext *tail_out; // The actual main output stream, if we're currently seeked back to write elsewhere
  56.     int64_t tail_pos, cur_pos, cur_start_pos;
  57.     int packets_written;
  58.     const char *stream_type_tag;
  59.     int nb_fragments, fragments_size, fragment_index;
  60.     Fragment **fragments;
  61.  
  62.     const char *fourcc;
  63.     char *private_str;
  64.     int packet_size;
  65.     int audio_tag;
  66. } OutputStream;
  67.  
  68. typedef struct {
  69.     const AVClass *class;  /* Class for private options. */
  70.     int window_size;
  71.     int extra_window_size;
  72.     int lookahead_count;
  73.     int min_frag_duration;
  74.     int remove_at_exit;
  75.     OutputStream *streams;
  76.     int has_video, has_audio;
  77.     int nb_fragments;
  78. } SmoothStreamingContext;
  79.  
  80. static int ism_write(void *opaque, uint8_t *buf, int buf_size)
  81. {
  82.     OutputStream *os = opaque;
  83.     if (os->out)
  84.         ffurl_write(os->out, buf, buf_size);
  85.     if (os->out2)
  86.         ffurl_write(os->out2, buf, buf_size);
  87.     os->cur_pos += buf_size;
  88.     if (os->cur_pos >= os->tail_pos)
  89.         os->tail_pos = os->cur_pos;
  90.     return buf_size;
  91. }
  92.  
  93. static int64_t ism_seek(void *opaque, int64_t offset, int whence)
  94. {
  95.     OutputStream *os = opaque;
  96.     int i;
  97.     if (whence != SEEK_SET)
  98.         return AVERROR(ENOSYS);
  99.     if (os->tail_out) {
  100.         if (os->out) {
  101.             ffurl_close(os->out);
  102.         }
  103.         if (os->out2) {
  104.             ffurl_close(os->out2);
  105.         }
  106.         os->out = os->tail_out;
  107.         os->out2 = NULL;
  108.         os->tail_out = NULL;
  109.     }
  110.     if (offset >= os->cur_start_pos) {
  111.         if (os->out)
  112.             ffurl_seek(os->out, offset - os->cur_start_pos, SEEK_SET);
  113.         os->cur_pos = offset;
  114.         return offset;
  115.     }
  116.     for (i = os->nb_fragments - 1; i >= 0; i--) {
  117.         Fragment *frag = os->fragments[i];
  118.         if (offset >= frag->start_pos && offset < frag->start_pos + frag->size) {
  119.             int ret;
  120.             AVDictionary *opts = NULL;
  121.             os->tail_out = os->out;
  122.             av_dict_set(&opts, "truncate", "0", 0);
  123.             ret = ffurl_open(&os->out, frag->file, AVIO_FLAG_READ_WRITE, &os->ctx->interrupt_callback, &opts);
  124.             av_dict_free(&opts);
  125.             if (ret < 0) {
  126.                 os->out = os->tail_out;
  127.                 os->tail_out = NULL;
  128.                 return ret;
  129.             }
  130.             av_dict_set(&opts, "truncate", "0", 0);
  131.             ffurl_open(&os->out2, frag->infofile, AVIO_FLAG_READ_WRITE, &os->ctx->interrupt_callback, &opts);
  132.             av_dict_free(&opts);
  133.             ffurl_seek(os->out, offset - frag->start_pos, SEEK_SET);
  134.             if (os->out2)
  135.                 ffurl_seek(os->out2, offset - frag->start_pos, SEEK_SET);
  136.             os->cur_pos = offset;
  137.             return offset;
  138.         }
  139.     }
  140.     return AVERROR(EIO);
  141. }
  142.  
  143. static void get_private_data(OutputStream *os)
  144. {
  145.     AVCodecContext *codec = os->ctx->streams[0]->codec;
  146.     uint8_t *ptr = codec->extradata;
  147.     int size = codec->extradata_size;
  148.     int i;
  149.     if (codec->codec_id == AV_CODEC_ID_H264) {
  150.         ff_avc_write_annexb_extradata(ptr, &ptr, &size);
  151.         if (!ptr)
  152.             ptr = codec->extradata;
  153.     }
  154.     if (!ptr)
  155.         return;
  156.     os->private_str = av_mallocz(2*size + 1);
  157.     for (i = 0; i < size; i++)
  158.         snprintf(&os->private_str[2*i], 3, "%02x", ptr[i]);
  159.     if (ptr != codec->extradata)
  160.         av_free(ptr);
  161. }
  162.  
  163. static void ism_free(AVFormatContext *s)
  164. {
  165.     SmoothStreamingContext *c = s->priv_data;
  166.     int i, j;
  167.     if (!c->streams)
  168.         return;
  169.     for (i = 0; i < s->nb_streams; i++) {
  170.         OutputStream *os = &c->streams[i];
  171.         ffurl_close(os->out);
  172.         ffurl_close(os->out2);
  173.         ffurl_close(os->tail_out);
  174.         os->out = os->out2 = os->tail_out = NULL;
  175.         if (os->ctx && os->ctx_inited)
  176.             av_write_trailer(os->ctx);
  177.         if (os->ctx && os->ctx->pb)
  178.             av_free(os->ctx->pb);
  179.         if (os->ctx)
  180.             avformat_free_context(os->ctx);
  181.         av_free(os->private_str);
  182.         for (j = 0; j < os->nb_fragments; j++)
  183.             av_free(os->fragments[j]);
  184.         av_free(os->fragments);
  185.     }
  186.     av_freep(&c->streams);
  187. }
  188.  
  189. static void output_chunk_list(OutputStream *os, AVIOContext *out, int final, int skip, int window_size)
  190. {
  191.     int removed = 0, i, start = 0;
  192.     if (os->nb_fragments <= 0)
  193.         return;
  194.     if (os->fragments[0]->n > 0)
  195.         removed = 1;
  196.     if (final)
  197.         skip = 0;
  198.     if (window_size)
  199.         start = FFMAX(os->nb_fragments - skip - window_size, 0);
  200.     for (i = start; i < os->nb_fragments - skip; i++) {
  201.         Fragment *frag = os->fragments[i];
  202.         if (!final || removed)
  203.             avio_printf(out, "<c t=\"%"PRIu64"\" d=\"%"PRIu64"\" />\n", frag->start_time, frag->duration);
  204.         else
  205.             avio_printf(out, "<c n=\"%d\" d=\"%"PRIu64"\" />\n", frag->n, frag->duration);
  206.     }
  207. }
  208.  
  209. static int write_manifest(AVFormatContext *s, int final)
  210. {
  211.     SmoothStreamingContext *c = s->priv_data;
  212.     AVIOContext *out;
  213.     char filename[1024], temp_filename[1024];
  214.     int ret, i, video_chunks = 0, audio_chunks = 0, video_streams = 0, audio_streams = 0;
  215.     int64_t duration = 0;
  216.  
  217.     snprintf(filename, sizeof(filename), "%s/Manifest", s->filename);
  218.     snprintf(temp_filename, sizeof(temp_filename), "%s/Manifest.tmp", s->filename);
  219.     ret = avio_open2(&out, temp_filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
  220.     if (ret < 0) {
  221.         av_log(s, AV_LOG_ERROR, "Unable to open %s for writing\n", temp_filename);
  222.         return ret;
  223.     }
  224.     avio_printf(out, "<?xml version=\"1.0\" encoding=\"utf-8\"?>\n");
  225.     for (i = 0; i < s->nb_streams; i++) {
  226.         OutputStream *os = &c->streams[i];
  227.         if (os->nb_fragments > 0) {
  228.             Fragment *last = os->fragments[os->nb_fragments - 1];
  229.             duration = last->start_time + last->duration;
  230.         }
  231.         if (s->streams[i]->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
  232.             video_chunks = os->nb_fragments;
  233.             video_streams++;
  234.         } else {
  235.             audio_chunks = os->nb_fragments;
  236.             audio_streams++;
  237.         }
  238.     }
  239.     if (!final) {
  240.         duration = 0;
  241.         video_chunks = audio_chunks = 0;
  242.     }
  243.     if (c->window_size) {
  244.         video_chunks = FFMIN(video_chunks, c->window_size);
  245.         audio_chunks = FFMIN(audio_chunks, c->window_size);
  246.     }
  247.     avio_printf(out, "<SmoothStreamingMedia MajorVersion=\"2\" MinorVersion=\"0\" Duration=\"%"PRIu64"\"", duration);
  248.     if (!final)
  249.         avio_printf(out, " IsLive=\"true\" LookAheadFragmentCount=\"%d\" DVRWindowLength=\"0\"", c->lookahead_count);
  250.     avio_printf(out, ">\n");
  251.     if (c->has_video) {
  252.         int last = -1, index = 0;
  253.         avio_printf(out, "<StreamIndex Type=\"video\" QualityLevels=\"%d\" Chunks=\"%d\" Url=\"QualityLevels({bitrate})/Fragments(video={start time})\">\n", video_streams, video_chunks);
  254.         for (i = 0; i < s->nb_streams; i++) {
  255.             OutputStream *os = &c->streams[i];
  256.             if (s->streams[i]->codec->codec_type != AVMEDIA_TYPE_VIDEO)
  257.                 continue;
  258.             last = i;
  259.             avio_printf(out, "<QualityLevel Index=\"%d\" Bitrate=\"%d\" FourCC=\"%s\" MaxWidth=\"%d\" MaxHeight=\"%d\" CodecPrivateData=\"%s\" />\n", index, s->streams[i]->codec->bit_rate, os->fourcc, s->streams[i]->codec->width, s->streams[i]->codec->height, os->private_str);
  260.             index++;
  261.         }
  262.         output_chunk_list(&c->streams[last], out, final, c->lookahead_count, c->window_size);
  263.         avio_printf(out, "</StreamIndex>\n");
  264.     }
  265.     if (c->has_audio) {
  266.         int last = -1, index = 0;
  267.         avio_printf(out, "<StreamIndex Type=\"audio\" QualityLevels=\"%d\" Chunks=\"%d\" Url=\"QualityLevels({bitrate})/Fragments(audio={start time})\">\n", audio_streams, audio_chunks);
  268.         for (i = 0; i < s->nb_streams; i++) {
  269.             OutputStream *os = &c->streams[i];
  270.             if (s->streams[i]->codec->codec_type != AVMEDIA_TYPE_AUDIO)
  271.                 continue;
  272.             last = i;
  273.             avio_printf(out, "<QualityLevel Index=\"%d\" Bitrate=\"%d\" FourCC=\"%s\" SamplingRate=\"%d\" Channels=\"%d\" BitsPerSample=\"16\" PacketSize=\"%d\" AudioTag=\"%d\" CodecPrivateData=\"%s\" />\n", index, s->streams[i]->codec->bit_rate, os->fourcc, s->streams[i]->codec->sample_rate, s->streams[i]->codec->channels, os->packet_size, os->audio_tag, os->private_str);
  274.             index++;
  275.         }
  276.         output_chunk_list(&c->streams[last], out, final, c->lookahead_count, c->window_size);
  277.         avio_printf(out, "</StreamIndex>\n");
  278.     }
  279.     avio_printf(out, "</SmoothStreamingMedia>\n");
  280.     avio_flush(out);
  281.     avio_close(out);
  282.     rename(temp_filename, filename);
  283.     return 0;
  284. }
  285.  
  286. static int ism_write_header(AVFormatContext *s)
  287. {
  288.     SmoothStreamingContext *c = s->priv_data;
  289.     int ret = 0, i;
  290.     AVOutputFormat *oformat;
  291.  
  292.     if (mkdir(s->filename, 0777) < 0) {
  293.         av_log(s, AV_LOG_ERROR, "mkdir failed\n");
  294.         ret = AVERROR(errno);
  295.         goto fail;
  296.     }
  297.  
  298.     oformat = av_guess_format("ismv", NULL, NULL);
  299.     if (!oformat) {
  300.         ret = AVERROR_MUXER_NOT_FOUND;
  301.         goto fail;
  302.     }
  303.  
  304.     c->streams = av_mallocz(sizeof(*c->streams) * s->nb_streams);
  305.     if (!c->streams) {
  306.         ret = AVERROR(ENOMEM);
  307.         goto fail;
  308.     }
  309.  
  310.     for (i = 0; i < s->nb_streams; i++) {
  311.         OutputStream *os = &c->streams[i];
  312.         AVFormatContext *ctx;
  313.         AVStream *st;
  314.         AVDictionary *opts = NULL;
  315.         char buf[10];
  316.  
  317.         if (!s->streams[i]->codec->bit_rate) {
  318.             av_log(s, AV_LOG_ERROR, "No bit rate set for stream %d\n", i);
  319.             ret = AVERROR(EINVAL);
  320.             goto fail;
  321.         }
  322.         snprintf(os->dirname, sizeof(os->dirname), "%s/QualityLevels(%d)", s->filename, s->streams[i]->codec->bit_rate);
  323.         if (mkdir(os->dirname, 0777) < 0) {
  324.             ret = AVERROR(errno);
  325.             av_log(s, AV_LOG_ERROR, "mkdir failed\n");
  326.             goto fail;
  327.         }
  328.  
  329.         ctx = avformat_alloc_context();
  330.         if (!ctx) {
  331.             ret = AVERROR(ENOMEM);
  332.             goto fail;
  333.         }
  334.         os->ctx = ctx;
  335.         ctx->oformat = oformat;
  336.         ctx->interrupt_callback = s->interrupt_callback;
  337.  
  338.         if (!(st = avformat_new_stream(ctx, NULL))) {
  339.             ret = AVERROR(ENOMEM);
  340.             goto fail;
  341.         }
  342.         avcodec_copy_context(st->codec, s->streams[i]->codec);
  343.         st->sample_aspect_ratio = s->streams[i]->sample_aspect_ratio;
  344.  
  345.         ctx->pb = avio_alloc_context(os->iobuf, sizeof(os->iobuf), AVIO_FLAG_WRITE, os, NULL, ism_write, ism_seek);
  346.         if (!ctx->pb) {
  347.             ret = AVERROR(ENOMEM);
  348.             goto fail;
  349.         }
  350.  
  351.         snprintf(buf, sizeof(buf), "%d", c->lookahead_count);
  352.         av_dict_set(&opts, "ism_lookahead", buf, 0);
  353.         av_dict_set(&opts, "movflags", "frag_custom", 0);
  354.         if ((ret = avformat_write_header(ctx, &opts)) < 0) {
  355.              goto fail;
  356.         }
  357.         os->ctx_inited = 1;
  358.         avio_flush(ctx->pb);
  359.         av_dict_free(&opts);
  360.         s->streams[i]->time_base = st->time_base;
  361.         if (st->codec->codec_type == AVMEDIA_TYPE_VIDEO) {
  362.             c->has_video = 1;
  363.             os->stream_type_tag = "video";
  364.             if (st->codec->codec_id == AV_CODEC_ID_H264) {
  365.                 os->fourcc = "H264";
  366.             } else if (st->codec->codec_id == AV_CODEC_ID_VC1) {
  367.                 os->fourcc = "WVC1";
  368.             } else {
  369.                 av_log(s, AV_LOG_ERROR, "Unsupported video codec\n");
  370.                 ret = AVERROR(EINVAL);
  371.                 goto fail;
  372.             }
  373.         } else {
  374.             c->has_audio = 1;
  375.             os->stream_type_tag = "audio";
  376.             if (st->codec->codec_id == AV_CODEC_ID_AAC) {
  377.                 os->fourcc = "AACL";
  378.                 os->audio_tag = 0xff;
  379.             } else if (st->codec->codec_id == AV_CODEC_ID_WMAPRO) {
  380.                 os->fourcc = "WMAP";
  381.                 os->audio_tag = 0x0162;
  382.             } else {
  383.                 av_log(s, AV_LOG_ERROR, "Unsupported audio codec\n");
  384.                 ret = AVERROR(EINVAL);
  385.                 goto fail;
  386.             }
  387.             os->packet_size = st->codec->block_align ? st->codec->block_align : 4;
  388.         }
  389.         get_private_data(os);
  390.     }
  391.  
  392.     if (!c->has_video && c->min_frag_duration <= 0) {
  393.         av_log(s, AV_LOG_WARNING, "no video stream and no min frag duration set\n");
  394.         ret = AVERROR(EINVAL);
  395.     }
  396.     ret = write_manifest(s, 0);
  397.  
  398. fail:
  399.     if (ret)
  400.         ism_free(s);
  401.     return ret;
  402. }
  403.  
  404. static int parse_fragment(AVFormatContext *s, const char *filename, int64_t *start_ts, int64_t *duration, int64_t *moof_size, int64_t size)
  405. {
  406.     AVIOContext *in;
  407.     int ret;
  408.     uint32_t len;
  409.     if ((ret = avio_open2(&in, filename, AVIO_FLAG_READ, &s->interrupt_callback, NULL)) < 0)
  410.         return ret;
  411.     ret = AVERROR(EIO);
  412.     *moof_size = avio_rb32(in);
  413.     if (*moof_size < 8 || *moof_size > size)
  414.         goto fail;
  415.     if (avio_rl32(in) != MKTAG('m','o','o','f'))
  416.         goto fail;
  417.     len = avio_rb32(in);
  418.     if (len > *moof_size)
  419.         goto fail;
  420.     if (avio_rl32(in) != MKTAG('m','f','h','d'))
  421.         goto fail;
  422.     avio_seek(in, len - 8, SEEK_CUR);
  423.     avio_rb32(in); /* traf size */
  424.     if (avio_rl32(in) != MKTAG('t','r','a','f'))
  425.         goto fail;
  426.     while (avio_tell(in) < *moof_size) {
  427.         uint32_t len = avio_rb32(in);
  428.         uint32_t tag = avio_rl32(in);
  429.         int64_t end = avio_tell(in) + len - 8;
  430.         if (len < 8 || len >= *moof_size)
  431.             goto fail;
  432.         if (tag == MKTAG('u','u','i','d')) {
  433.             static const uint8_t tfxd[] = {
  434.                 0x6d, 0x1d, 0x9b, 0x05, 0x42, 0xd5, 0x44, 0xe6,
  435.                 0x80, 0xe2, 0x14, 0x1d, 0xaf, 0xf7, 0x57, 0xb2
  436.             };
  437.             uint8_t uuid[16];
  438.             avio_read(in, uuid, 16);
  439.             if (!memcmp(uuid, tfxd, 16) && len >= 8 + 16 + 4 + 16) {
  440.                 avio_seek(in, 4, SEEK_CUR);
  441.                 *start_ts = avio_rb64(in);
  442.                 *duration = avio_rb64(in);
  443.                 ret = 0;
  444.                 break;
  445.             }
  446.         }
  447.         avio_seek(in, end, SEEK_SET);
  448.     }
  449. fail:
  450.     avio_close(in);
  451.     return ret;
  452. }
  453.  
  454. static int add_fragment(OutputStream *os, const char *file, const char *infofile, int64_t start_time, int64_t duration, int64_t start_pos, int64_t size)
  455. {
  456.     int err;
  457.     Fragment *frag;
  458.     if (os->nb_fragments >= os->fragments_size) {
  459.         os->fragments_size = (os->fragments_size + 1) * 2;
  460.         if ((err = av_reallocp(&os->fragments, sizeof(*os->fragments) *
  461.                                os->fragments_size)) < 0) {
  462.             os->fragments_size = 0;
  463.             os->nb_fragments = 0;
  464.             return err;
  465.         }
  466.     }
  467.     frag = av_mallocz(sizeof(*frag));
  468.     if (!frag)
  469.         return AVERROR(ENOMEM);
  470.     av_strlcpy(frag->file, file, sizeof(frag->file));
  471.     av_strlcpy(frag->infofile, infofile, sizeof(frag->infofile));
  472.     frag->start_time = start_time;
  473.     frag->duration = duration;
  474.     frag->start_pos = start_pos;
  475.     frag->size = size;
  476.     frag->n = os->fragment_index;
  477.     os->fragments[os->nb_fragments++] = frag;
  478.     os->fragment_index++;
  479.     return 0;
  480. }
  481.  
  482. static int copy_moof(AVFormatContext *s, const char* infile, const char *outfile, int64_t size)
  483. {
  484.     AVIOContext *in, *out;
  485.     int ret = 0;
  486.     if ((ret = avio_open2(&in, infile, AVIO_FLAG_READ, &s->interrupt_callback, NULL)) < 0)
  487.         return ret;
  488.     if ((ret = avio_open2(&out, outfile, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL)) < 0) {
  489.         avio_close(in);
  490.         return ret;
  491.     }
  492.     while (size > 0) {
  493.         uint8_t buf[8192];
  494.         int n = FFMIN(size, sizeof(buf));
  495.         n = avio_read(in, buf, n);
  496.         if (n <= 0) {
  497.             ret = AVERROR(EIO);
  498.             break;
  499.         }
  500.         avio_write(out, buf, n);
  501.         size -= n;
  502.     }
  503.     avio_flush(out);
  504.     avio_close(out);
  505.     avio_close(in);
  506.     return ret;
  507. }
  508.  
  509. static int ism_flush(AVFormatContext *s, int final)
  510. {
  511.     SmoothStreamingContext *c = s->priv_data;
  512.     int i, ret = 0;
  513.  
  514.     for (i = 0; i < s->nb_streams; i++) {
  515.         OutputStream *os = &c->streams[i];
  516.         char filename[1024], target_filename[1024], header_filename[1024];
  517.         int64_t start_pos = os->tail_pos, size;
  518.         int64_t start_ts, duration, moof_size;
  519.         if (!os->packets_written)
  520.             continue;
  521.  
  522.         snprintf(filename, sizeof(filename), "%s/temp", os->dirname);
  523.         ret = ffurl_open(&os->out, filename, AVIO_FLAG_WRITE, &s->interrupt_callback, NULL);
  524.         if (ret < 0)
  525.             break;
  526.         os->cur_start_pos = os->tail_pos;
  527.         av_write_frame(os->ctx, NULL);
  528.         avio_flush(os->ctx->pb);
  529.         os->packets_written = 0;
  530.         if (!os->out || os->tail_out)
  531.             return AVERROR(EIO);
  532.  
  533.         ffurl_close(os->out);
  534.         os->out = NULL;
  535.         size = os->tail_pos - start_pos;
  536.         if ((ret = parse_fragment(s, filename, &start_ts, &duration, &moof_size, size)) < 0)
  537.             break;
  538.         snprintf(header_filename, sizeof(header_filename), "%s/FragmentInfo(%s=%"PRIu64")", os->dirname, os->stream_type_tag, start_ts);
  539.         snprintf(target_filename, sizeof(target_filename), "%s/Fragments(%s=%"PRIu64")", os->dirname, os->stream_type_tag, start_ts);
  540.         copy_moof(s, filename, header_filename, moof_size);
  541.         rename(filename, target_filename);
  542.         add_fragment(os, target_filename, header_filename, start_ts, duration, start_pos, size);
  543.     }
  544.  
  545.     if (c->window_size || (final && c->remove_at_exit)) {
  546.         for (i = 0; i < s->nb_streams; i++) {
  547.             OutputStream *os = &c->streams[i];
  548.             int j;
  549.             int remove = os->nb_fragments - c->window_size - c->extra_window_size - c->lookahead_count;
  550.             if (final && c->remove_at_exit)
  551.                 remove = os->nb_fragments;
  552.             if (remove > 0) {
  553.                 for (j = 0; j < remove; j++) {
  554.                     unlink(os->fragments[j]->file);
  555.                     unlink(os->fragments[j]->infofile);
  556.                     av_free(os->fragments[j]);
  557.                 }
  558.                 os->nb_fragments -= remove;
  559.                 memmove(os->fragments, os->fragments + remove, os->nb_fragments * sizeof(*os->fragments));
  560.             }
  561.             if (final && c->remove_at_exit)
  562.                 rmdir(os->dirname);
  563.         }
  564.     }
  565.  
  566.     if (ret >= 0)
  567.         ret = write_manifest(s, final);
  568.     return ret;
  569. }
  570.  
  571. static int ism_write_packet(AVFormatContext *s, AVPacket *pkt)
  572. {
  573.     SmoothStreamingContext *c = s->priv_data;
  574.     AVStream *st = s->streams[pkt->stream_index];
  575.     OutputStream *os = &c->streams[pkt->stream_index];
  576.     int64_t end_dts = (c->nb_fragments + 1LL) * c->min_frag_duration;
  577.     int ret;
  578.  
  579.     if (st->first_dts == AV_NOPTS_VALUE)
  580.         st->first_dts = pkt->dts;
  581.  
  582.     if ((!c->has_video || st->codec->codec_type == AVMEDIA_TYPE_VIDEO) &&
  583.         av_compare_ts(pkt->dts - st->first_dts, st->time_base,
  584.                       end_dts, AV_TIME_BASE_Q) >= 0 &&
  585.         pkt->flags & AV_PKT_FLAG_KEY && os->packets_written) {
  586.  
  587.         if ((ret = ism_flush(s, 0)) < 0)
  588.             return ret;
  589.         c->nb_fragments++;
  590.     }
  591.  
  592.     os->packets_written++;
  593.     return ff_write_chained(os->ctx, 0, pkt, s);
  594. }
  595.  
  596. static int ism_write_trailer(AVFormatContext *s)
  597. {
  598.     SmoothStreamingContext *c = s->priv_data;
  599.     ism_flush(s, 1);
  600.  
  601.     if (c->remove_at_exit) {
  602.         char filename[1024];
  603.         snprintf(filename, sizeof(filename), "%s/Manifest", s->filename);
  604.         unlink(filename);
  605.         rmdir(s->filename);
  606.     }
  607.  
  608.     ism_free(s);
  609.     return 0;
  610. }
  611.  
  612. #define OFFSET(x) offsetof(SmoothStreamingContext, x)
  613. #define E AV_OPT_FLAG_ENCODING_PARAM
  614. static const AVOption options[] = {
  615.     { "window_size", "number of fragments kept in the manifest", OFFSET(window_size), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, INT_MAX, E },
  616.     { "extra_window_size", "number of fragments kept outside of the manifest before removing from disk", OFFSET(extra_window_size), AV_OPT_TYPE_INT, { .i64 = 5 }, 0, INT_MAX, E },
  617.     { "lookahead_count", "number of lookahead fragments", OFFSET(lookahead_count), AV_OPT_TYPE_INT, { .i64 = 2 }, 0, INT_MAX, E },
  618.     { "min_frag_duration", "minimum fragment duration (in microseconds)", OFFSET(min_frag_duration), AV_OPT_TYPE_INT64, { .i64 = 5000000 }, 0, INT_MAX, E },
  619.     { "remove_at_exit", "remove all fragments when finished", OFFSET(remove_at_exit), AV_OPT_TYPE_INT, { .i64 = 0 }, 0, 1, E },
  620.     { NULL },
  621. };
  622.  
  623. static const AVClass ism_class = {
  624.     .class_name = "smooth streaming muxer",
  625.     .item_name  = av_default_item_name,
  626.     .option     = options,
  627.     .version    = LIBAVUTIL_VERSION_INT,
  628. };
  629.  
  630.  
  631. AVOutputFormat ff_smoothstreaming_muxer = {
  632.     .name           = "smoothstreaming",
  633.     .long_name      = NULL_IF_CONFIG_SMALL("Smooth Streaming Muxer"),
  634.     .priv_data_size = sizeof(SmoothStreamingContext),
  635.     .audio_codec    = AV_CODEC_ID_AAC,
  636.     .video_codec    = AV_CODEC_ID_H264,
  637.     .flags          = AVFMT_GLOBALHEADER | AVFMT_NOFILE,
  638.     .write_header   = ism_write_header,
  639.     .write_packet   = ism_write_packet,
  640.     .write_trailer  = ism_write_trailer,
  641.     .codec_tag      = (const AVCodecTag* const []){ ff_mp4_obj_type, 0 },
  642.     .priv_class     = &ism_class,
  643. };
  644.