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4349 | Serge | 1 | /* |
2 | * Apple HTTP Live Streaming Protocol Handler |
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3 | * Copyright (c) 2010 Martin Storsjo |
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4 | * |
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5 | * This file is part of FFmpeg. |
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6 | * |
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7 | * FFmpeg is free software; you can redistribute it and/or |
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8 | * modify it under the terms of the GNU Lesser General Public |
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9 | * License as published by the Free Software Foundation; either |
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10 | * version 2.1 of the License, or (at your option) any later version. |
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11 | * |
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12 | * FFmpeg is distributed in the hope that it will be useful, |
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13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
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14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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15 | * Lesser General Public License for more details. |
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16 | * |
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17 | * You should have received a copy of the GNU Lesser General Public |
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18 | * License along with FFmpeg; if not, write to the Free Software |
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19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
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20 | */ |
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21 | |||
22 | /** |
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23 | * @file |
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24 | * Apple HTTP Live Streaming Protocol Handler |
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25 | * http://tools.ietf.org/html/draft-pantos-http-live-streaming |
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26 | */ |
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27 | |||
28 | #include "libavutil/avstring.h" |
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29 | #include "libavutil/time.h" |
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30 | #include "avformat.h" |
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31 | #include "internal.h" |
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32 | #include "url.h" |
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33 | #include "version.h" |
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34 | |||
35 | /* |
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36 | * An apple http stream consists of a playlist with media segment files, |
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37 | * played sequentially. There may be several playlists with the same |
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38 | * video content, in different bandwidth variants, that are played in |
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39 | * parallel (preferably only one bandwidth variant at a time). In this case, |
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40 | * the user supplied the url to a main playlist that only lists the variant |
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41 | * playlists. |
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42 | * |
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43 | * If the main playlist doesn't point at any variants, we still create |
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44 | * one anonymous toplevel variant for this, to maintain the structure. |
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45 | */ |
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46 | |||
47 | struct segment { |
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48 | int64_t duration; |
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49 | char url[MAX_URL_SIZE]; |
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50 | }; |
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51 | |||
52 | struct variant { |
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53 | int bandwidth; |
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54 | char url[MAX_URL_SIZE]; |
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55 | }; |
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56 | |||
57 | typedef struct HLSContext { |
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58 | char playlisturl[MAX_URL_SIZE]; |
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59 | int64_t target_duration; |
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60 | int start_seq_no; |
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61 | int finished; |
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62 | int n_segments; |
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63 | struct segment **segments; |
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64 | int n_variants; |
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65 | struct variant **variants; |
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66 | int cur_seq_no; |
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67 | URLContext *seg_hd; |
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68 | int64_t last_load_time; |
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69 | } HLSContext; |
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70 | |||
71 | static int read_chomp_line(AVIOContext *s, char *buf, int maxlen) |
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72 | { |
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73 | int len = ff_get_line(s, buf, maxlen); |
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74 | while (len > 0 && av_isspace(buf[len - 1])) |
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75 | buf[--len] = '\0'; |
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76 | return len; |
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77 | } |
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78 | |||
79 | static void free_segment_list(HLSContext *s) |
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80 | { |
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81 | int i; |
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82 | for (i = 0; i < s->n_segments; i++) |
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83 | av_free(s->segments[i]); |
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84 | av_freep(&s->segments); |
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85 | s->n_segments = 0; |
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86 | } |
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87 | |||
88 | static void free_variant_list(HLSContext *s) |
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89 | { |
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90 | int i; |
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91 | for (i = 0; i < s->n_variants; i++) |
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92 | av_free(s->variants[i]); |
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93 | av_freep(&s->variants); |
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94 | s->n_variants = 0; |
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95 | } |
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96 | |||
97 | struct variant_info { |
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98 | char bandwidth[20]; |
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99 | }; |
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100 | |||
101 | static void handle_variant_args(struct variant_info *info, const char *key, |
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102 | int key_len, char **dest, int *dest_len) |
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103 | { |
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104 | if (!strncmp(key, "BANDWIDTH=", key_len)) { |
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105 | *dest = info->bandwidth; |
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106 | *dest_len = sizeof(info->bandwidth); |
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107 | } |
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108 | } |
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109 | |||
110 | static int parse_playlist(URLContext *h, const char *url) |
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111 | { |
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112 | HLSContext *s = h->priv_data; |
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113 | AVIOContext *in; |
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114 | int ret = 0, is_segment = 0, is_variant = 0, bandwidth = 0; |
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115 | int64_t duration = 0; |
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116 | char line[1024]; |
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117 | const char *ptr; |
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118 | |||
119 | if ((ret = avio_open2(&in, url, AVIO_FLAG_READ, |
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120 | &h->interrupt_callback, NULL)) < 0) |
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121 | return ret; |
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122 | |||
123 | read_chomp_line(in, line, sizeof(line)); |
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124 | if (strcmp(line, "#EXTM3U")) |
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125 | return AVERROR_INVALIDDATA; |
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126 | |||
127 | free_segment_list(s); |
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128 | s->finished = 0; |
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129 | while (!url_feof(in)) { |
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130 | read_chomp_line(in, line, sizeof(line)); |
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131 | if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) { |
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132 | struct variant_info info = {{0}}; |
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133 | is_variant = 1; |
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134 | ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args, |
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135 | &info); |
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136 | bandwidth = atoi(info.bandwidth); |
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137 | } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) { |
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138 | s->target_duration = atoi(ptr) * AV_TIME_BASE; |
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139 | } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) { |
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140 | s->start_seq_no = atoi(ptr); |
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141 | } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) { |
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142 | s->finished = 1; |
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143 | } else if (av_strstart(line, "#EXTINF:", &ptr)) { |
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144 | is_segment = 1; |
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145 | duration = atof(ptr) * AV_TIME_BASE; |
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146 | } else if (av_strstart(line, "#", NULL)) { |
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147 | continue; |
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148 | } else if (line[0]) { |
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149 | if (is_segment) { |
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150 | struct segment *seg = av_malloc(sizeof(struct segment)); |
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151 | if (!seg) { |
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152 | ret = AVERROR(ENOMEM); |
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153 | goto fail; |
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154 | } |
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155 | seg->duration = duration; |
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156 | ff_make_absolute_url(seg->url, sizeof(seg->url), url, line); |
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157 | dynarray_add(&s->segments, &s->n_segments, seg); |
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158 | is_segment = 0; |
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159 | } else if (is_variant) { |
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160 | struct variant *var = av_malloc(sizeof(struct variant)); |
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161 | if (!var) { |
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162 | ret = AVERROR(ENOMEM); |
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163 | goto fail; |
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164 | } |
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165 | var->bandwidth = bandwidth; |
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166 | ff_make_absolute_url(var->url, sizeof(var->url), url, line); |
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167 | dynarray_add(&s->variants, &s->n_variants, var); |
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168 | is_variant = 0; |
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169 | } |
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170 | } |
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171 | } |
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172 | s->last_load_time = av_gettime(); |
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173 | |||
174 | fail: |
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175 | avio_close(in); |
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176 | return ret; |
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177 | } |
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178 | |||
179 | static int hls_close(URLContext *h) |
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180 | { |
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181 | HLSContext *s = h->priv_data; |
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182 | |||
183 | free_segment_list(s); |
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184 | free_variant_list(s); |
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185 | ffurl_close(s->seg_hd); |
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186 | return 0; |
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187 | } |
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188 | |||
189 | static int hls_open(URLContext *h, const char *uri, int flags) |
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190 | { |
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191 | HLSContext *s = h->priv_data; |
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192 | int ret, i; |
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193 | const char *nested_url; |
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194 | |||
195 | if (flags & AVIO_FLAG_WRITE) |
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196 | return AVERROR(ENOSYS); |
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197 | |||
198 | h->is_streamed = 1; |
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199 | |||
200 | if (av_strstart(uri, "hls+", &nested_url)) { |
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201 | av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl)); |
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202 | } else if (av_strstart(uri, "hls://", &nested_url)) { |
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203 | av_log(h, AV_LOG_ERROR, |
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204 | "No nested protocol specified. Specify e.g. hls+http://%s\n", |
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205 | nested_url); |
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206 | ret = AVERROR(EINVAL); |
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207 | goto fail; |
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208 | } else { |
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209 | av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri); |
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210 | ret = AVERROR(EINVAL); |
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211 | goto fail; |
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212 | } |
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213 | av_log(h, AV_LOG_WARNING, |
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214 | "Using the hls protocol is discouraged, please try using the " |
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215 | "hls demuxer instead. The hls demuxer should be more complete " |
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216 | "and work as well as the protocol implementation. (If not, " |
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217 | "please report it.) To use the demuxer, simply use %s as url.\n", |
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218 | s->playlisturl); |
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219 | |||
220 | if ((ret = parse_playlist(h, s->playlisturl)) < 0) |
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221 | goto fail; |
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222 | |||
223 | if (s->n_segments == 0 && s->n_variants > 0) { |
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224 | int max_bandwidth = 0, maxvar = -1; |
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225 | for (i = 0; i < s->n_variants; i++) { |
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226 | if (s->variants[i]->bandwidth > max_bandwidth || i == 0) { |
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227 | max_bandwidth = s->variants[i]->bandwidth; |
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228 | maxvar = i; |
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229 | } |
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230 | } |
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231 | av_strlcpy(s->playlisturl, s->variants[maxvar]->url, |
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232 | sizeof(s->playlisturl)); |
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233 | if ((ret = parse_playlist(h, s->playlisturl)) < 0) |
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234 | goto fail; |
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235 | } |
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236 | |||
237 | if (s->n_segments == 0) { |
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238 | av_log(h, AV_LOG_WARNING, "Empty playlist\n"); |
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239 | ret = AVERROR(EIO); |
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240 | goto fail; |
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241 | } |
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242 | s->cur_seq_no = s->start_seq_no; |
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243 | if (!s->finished && s->n_segments >= 3) |
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244 | s->cur_seq_no = s->start_seq_no + s->n_segments - 3; |
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245 | |||
246 | return 0; |
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247 | |||
248 | fail: |
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249 | hls_close(h); |
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250 | return ret; |
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251 | } |
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252 | |||
253 | static int hls_read(URLContext *h, uint8_t *buf, int size) |
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254 | { |
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255 | HLSContext *s = h->priv_data; |
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256 | const char *url; |
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257 | int ret; |
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258 | int64_t reload_interval; |
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259 | |||
260 | start: |
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261 | if (s->seg_hd) { |
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262 | ret = ffurl_read(s->seg_hd, buf, size); |
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263 | if (ret > 0) |
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264 | return ret; |
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265 | } |
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266 | if (s->seg_hd) { |
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267 | ffurl_close(s->seg_hd); |
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268 | s->seg_hd = NULL; |
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269 | s->cur_seq_no++; |
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270 | } |
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271 | reload_interval = s->n_segments > 0 ? |
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272 | s->segments[s->n_segments - 1]->duration : |
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273 | s->target_duration; |
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274 | retry: |
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275 | if (!s->finished) { |
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276 | int64_t now = av_gettime(); |
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277 | if (now - s->last_load_time >= reload_interval) { |
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278 | if ((ret = parse_playlist(h, s->playlisturl)) < 0) |
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279 | return ret; |
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280 | /* If we need to reload the playlist again below (if |
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281 | * there's still no more segments), switch to a reload |
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282 | * interval of half the target duration. */ |
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283 | reload_interval = s->target_duration / 2; |
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284 | } |
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285 | } |
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286 | if (s->cur_seq_no < s->start_seq_no) { |
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287 | av_log(h, AV_LOG_WARNING, |
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288 | "skipping %d segments ahead, expired from playlist\n", |
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289 | s->start_seq_no - s->cur_seq_no); |
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290 | s->cur_seq_no = s->start_seq_no; |
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291 | } |
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292 | if (s->cur_seq_no - s->start_seq_no >= s->n_segments) { |
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293 | if (s->finished) |
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294 | return AVERROR_EOF; |
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295 | while (av_gettime() - s->last_load_time < reload_interval) { |
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296 | if (ff_check_interrupt(&h->interrupt_callback)) |
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297 | return AVERROR_EXIT; |
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298 | av_usleep(100*1000); |
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299 | } |
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300 | goto retry; |
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301 | } |
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302 | url = s->segments[s->cur_seq_no - s->start_seq_no]->url, |
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303 | av_log(h, AV_LOG_DEBUG, "opening %s\n", url); |
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304 | ret = ffurl_open(&s->seg_hd, url, AVIO_FLAG_READ, |
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305 | &h->interrupt_callback, NULL); |
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306 | if (ret < 0) { |
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307 | if (ff_check_interrupt(&h->interrupt_callback)) |
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308 | return AVERROR_EXIT; |
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309 | av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url); |
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310 | s->cur_seq_no++; |
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311 | goto retry; |
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312 | } |
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313 | goto start; |
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314 | } |
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315 | |||
316 | URLProtocol ff_hls_protocol = { |
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317 | .name = "hls", |
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318 | .url_open = hls_open, |
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319 | .url_read = hls_read, |
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320 | .url_close = hls_close, |
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321 | .flags = URL_PROTOCOL_FLAG_NESTED_SCHEME, |
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322 | .priv_data_size = sizeof(HLSContext), |
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323 | };>>>>>>>>>> |