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Rev | Author | Line No. | Line |
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4349 | Serge | 1 | /* |
2 | * MOV, 3GP, MP4 muxer RTP hinting |
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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 | #include "movenc.h" |
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23 | #include "libavutil/intreadwrite.h" |
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24 | #include "internal.h" |
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25 | #include "rtpenc_chain.h" |
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26 | #include "avio_internal.h" |
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27 | #include "rtp.h" |
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28 | |||
29 | int ff_mov_init_hinting(AVFormatContext *s, int index, int src_index) |
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30 | { |
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31 | MOVMuxContext *mov = s->priv_data; |
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32 | MOVTrack *track = &mov->tracks[index]; |
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33 | MOVTrack *src_track = &mov->tracks[src_index]; |
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34 | AVStream *src_st = s->streams[src_index]; |
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35 | int ret = AVERROR(ENOMEM); |
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36 | |||
37 | track->tag = MKTAG('r','t','p',' '); |
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38 | track->src_track = src_index; |
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39 | |||
40 | track->enc = avcodec_alloc_context3(NULL); |
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41 | if (!track->enc) |
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42 | goto fail; |
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43 | track->enc->codec_type = AVMEDIA_TYPE_DATA; |
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44 | track->enc->codec_tag = track->tag; |
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45 | |||
46 | ret = ff_rtp_chain_mux_open(&track->rtp_ctx, s, src_st, NULL, |
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47 | RTP_MAX_PACKET_SIZE, src_index); |
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48 | if (ret < 0) |
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49 | goto fail; |
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50 | |||
51 | /* Copy the RTP AVStream timebase back to the hint AVStream */ |
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52 | track->timescale = track->rtp_ctx->streams[0]->time_base.den; |
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53 | |||
54 | /* Mark the hinted track that packets written to it should be |
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55 | * sent to this track for hinting. */ |
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56 | src_track->hint_track = index; |
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57 | return 0; |
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58 | fail: |
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59 | av_log(s, AV_LOG_WARNING, |
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60 | "Unable to initialize hinting of stream %d\n", src_index); |
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61 | av_freep(&track->enc); |
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62 | /* Set a default timescale, to avoid crashes in av_dump_format */ |
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63 | track->timescale = 90000; |
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64 | return ret; |
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65 | } |
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66 | |||
67 | /** |
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68 | * Remove the first sample from the sample queue. |
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69 | */ |
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70 | static void sample_queue_pop(HintSampleQueue *queue) |
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71 | { |
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72 | if (queue->len <= 0) |
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73 | return; |
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74 | if (queue->samples[0].own_data) |
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75 | av_free(queue->samples[0].data); |
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76 | queue->len--; |
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77 | memmove(queue->samples, queue->samples + 1, sizeof(HintSample)*queue->len); |
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78 | } |
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79 | |||
80 | /** |
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81 | * Empty the sample queue, releasing all memory. |
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82 | */ |
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83 | static void sample_queue_free(HintSampleQueue *queue) |
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84 | { |
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85 | int i; |
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86 | for (i = 0; i < queue->len; i++) |
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87 | if (queue->samples[i].own_data) |
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88 | av_free(queue->samples[i].data); |
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89 | av_freep(&queue->samples); |
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90 | queue->len = 0; |
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91 | queue->size = 0; |
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92 | } |
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93 | |||
94 | /** |
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95 | * Add a reference to the sample data to the sample queue. The data is |
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96 | * not copied. sample_queue_retain should be called before pkt->data |
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97 | * is reused/freed. |
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98 | */ |
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99 | static void sample_queue_push(HintSampleQueue *queue, uint8_t *data, int size, |
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100 | int sample) |
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101 | { |
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102 | /* No need to keep track of smaller samples, since describing them |
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103 | * with immediates is more efficient. */ |
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104 | if (size <= 14) |
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105 | return; |
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106 | if (!queue->samples || queue->len >= queue->size) { |
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107 | HintSample *samples; |
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108 | samples = av_realloc_array(queue->samples, queue->size + 10, sizeof(HintSample)); |
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109 | if (!samples) |
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110 | return; |
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111 | queue->size += 10; |
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112 | queue->samples = samples; |
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113 | } |
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114 | queue->samples[queue->len].data = data; |
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115 | queue->samples[queue->len].size = size; |
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116 | queue->samples[queue->len].sample_number = sample; |
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117 | queue->samples[queue->len].offset = 0; |
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118 | queue->samples[queue->len].own_data = 0; |
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119 | queue->len++; |
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120 | } |
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121 | |||
122 | /** |
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123 | * Make local copies of all referenced sample data in the queue. |
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124 | */ |
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125 | static void sample_queue_retain(HintSampleQueue *queue) |
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126 | { |
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127 | int i; |
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128 | for (i = 0; i < queue->len; ) { |
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129 | HintSample *sample = &queue->samples[i]; |
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130 | if (!sample->own_data) { |
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131 | uint8_t *ptr = av_malloc(sample->size); |
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132 | if (!ptr) { |
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133 | /* Unable to allocate memory for this one, remove it */ |
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134 | memmove(queue->samples + i, queue->samples + i + 1, |
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135 | sizeof(HintSample)*(queue->len - i - 1)); |
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136 | queue->len--; |
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137 | continue; |
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138 | } |
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139 | memcpy(ptr, sample->data, sample->size); |
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140 | sample->data = ptr; |
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141 | sample->own_data = 1; |
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142 | } |
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143 | i++; |
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144 | } |
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145 | } |
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146 | |||
147 | /** |
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148 | * Find matches of needle[n_pos ->] within haystack. If a sufficiently |
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149 | * large match is found, matching bytes before n_pos are included |
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150 | * in the match, too (within the limits of the arrays). |
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151 | * |
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152 | * @param haystack buffer that may contain parts of needle |
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153 | * @param h_len length of the haystack buffer |
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154 | * @param needle buffer containing source data that have been used to |
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155 | * construct haystack |
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156 | * @param n_pos start position in needle used for looking for matches |
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157 | * @param n_len length of the needle buffer |
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158 | * @param match_h_offset_ptr offset of the first matching byte within haystack |
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159 | * @param match_n_offset_ptr offset of the first matching byte within needle |
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160 | * @param match_len_ptr length of the matched segment |
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161 | * @return 0 if a match was found, < 0 if no match was found |
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162 | */ |
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163 | static int match_segments(const uint8_t *haystack, int h_len, |
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164 | const uint8_t *needle, int n_pos, int n_len, |
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165 | int *match_h_offset_ptr, int *match_n_offset_ptr, |
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166 | int *match_len_ptr) |
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167 | { |
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168 | int h_pos; |
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169 | for (h_pos = 0; h_pos < h_len; h_pos++) { |
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170 | int match_len = 0; |
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171 | int match_h_pos, match_n_pos; |
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172 | |||
173 | /* Check how many bytes match at needle[n_pos] and haystack[h_pos] */ |
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174 | while (h_pos + match_len < h_len && n_pos + match_len < n_len && |
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175 | needle[n_pos + match_len] == haystack[h_pos + match_len]) |
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176 | match_len++; |
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177 | if (match_len <= 8) |
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178 | continue; |
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179 | |||
180 | /* If a sufficiently large match was found, try to expand |
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181 | * the matched segment backwards. */ |
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182 | match_h_pos = h_pos; |
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183 | match_n_pos = n_pos; |
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184 | while (match_n_pos > 0 && match_h_pos > 0 && |
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185 | needle[match_n_pos - 1] == haystack[match_h_pos - 1]) { |
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186 | match_n_pos--; |
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187 | match_h_pos--; |
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188 | match_len++; |
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189 | } |
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190 | if (match_len <= 14) |
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191 | continue; |
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192 | *match_h_offset_ptr = match_h_pos; |
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193 | *match_n_offset_ptr = match_n_pos; |
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194 | *match_len_ptr = match_len; |
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195 | return 0; |
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196 | } |
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197 | return -1; |
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198 | } |
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199 | |||
200 | /** |
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201 | * Look for segments in samples in the sample queue matching the data |
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202 | * in ptr. Samples not matching are removed from the queue. If a match |
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203 | * is found, the next time it will look for matches starting from the |
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204 | * end of the previous matched segment. |
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205 | * |
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206 | * @param data data to find matches for in the sample queue |
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207 | * @param len length of the data buffer |
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208 | * @param queue samples used for looking for matching segments |
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209 | * @param pos the offset in data of the matched segment |
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210 | * @param match_sample the number of the sample that contained the match |
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211 | * @param match_offset the offset of the matched segment within the sample |
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212 | * @param match_len the length of the matched segment |
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213 | * @return 0 if a match was found, < 0 if no match was found |
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214 | */ |
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215 | static int find_sample_match(const uint8_t *data, int len, |
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216 | HintSampleQueue *queue, int *pos, |
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217 | int *match_sample, int *match_offset, |
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218 | int *match_len) |
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219 | { |
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220 | while (queue->len > 0) { |
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221 | HintSample *sample = &queue->samples[0]; |
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222 | /* If looking for matches in a new sample, skip the first 5 bytes, |
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223 | * since they often may be modified/removed in the output packet. */ |
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224 | if (sample->offset == 0 && sample->size > 5) |
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225 | sample->offset = 5; |
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226 | |||
227 | if (match_segments(data, len, sample->data, sample->offset, |
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228 | sample->size, pos, match_offset, match_len) == 0) { |
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229 | *match_sample = sample->sample_number; |
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230 | /* Next time, look for matches at this offset, with a little |
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231 | * margin to this match. */ |
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232 | sample->offset = *match_offset + *match_len + 5; |
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233 | if (sample->offset + 10 >= sample->size) |
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234 | sample_queue_pop(queue); /* Not enough useful data left */ |
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235 | return 0; |
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236 | } |
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237 | |||
238 | if (sample->offset < 10 && sample->size > 20) { |
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239 | /* No match found from the start of the sample, |
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240 | * try from the middle of the sample instead. */ |
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241 | sample->offset = sample->size/2; |
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242 | } else { |
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243 | /* No match for this sample, remove it */ |
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244 | sample_queue_pop(queue); |
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245 | } |
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246 | } |
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247 | return -1; |
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248 | } |
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249 | |||
250 | static void output_immediate(const uint8_t *data, int size, |
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251 | AVIOContext *out, int *entries) |
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252 | { |
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253 | while (size > 0) { |
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254 | int len = size; |
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255 | if (len > 14) |
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256 | len = 14; |
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257 | avio_w8(out, 1); /* immediate constructor */ |
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258 | avio_w8(out, len); /* amount of valid data */ |
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259 | avio_write(out, data, len); |
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260 | data += len; |
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261 | size -= len; |
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262 | |||
263 | for (; len < 14; len++) |
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264 | avio_w8(out, 0); |
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265 | |||
266 | (*entries)++; |
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267 | } |
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268 | } |
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269 | |||
270 | static void output_match(AVIOContext *out, int match_sample, |
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271 | int match_offset, int match_len, int *entries) |
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272 | { |
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273 | avio_w8(out, 2); /* sample constructor */ |
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274 | avio_w8(out, 0); /* track reference */ |
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275 | avio_wb16(out, match_len); |
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276 | avio_wb32(out, match_sample); |
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277 | avio_wb32(out, match_offset); |
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278 | avio_wb16(out, 1); /* bytes per block */ |
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279 | avio_wb16(out, 1); /* samples per block */ |
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280 | (*entries)++; |
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281 | } |
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282 | |||
283 | static void describe_payload(const uint8_t *data, int size, |
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284 | AVIOContext *out, int *entries, |
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285 | HintSampleQueue *queue) |
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286 | { |
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287 | /* Describe the payload using different constructors */ |
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288 | while (size > 0) { |
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289 | int match_sample, match_offset, match_len, pos; |
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290 | if (find_sample_match(data, size, queue, &pos, &match_sample, |
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291 | &match_offset, &match_len) < 0) |
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292 | break; |
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293 | output_immediate(data, pos, out, entries); |
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294 | data += pos; |
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295 | size -= pos; |
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296 | output_match(out, match_sample, match_offset, match_len, entries); |
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297 | data += match_len; |
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298 | size -= match_len; |
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299 | } |
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300 | output_immediate(data, size, out, entries); |
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301 | } |
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302 | |||
303 | /** |
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304 | * Write an RTP hint (that may contain one or more RTP packets) |
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305 | * for the packets in data. data contains one or more packets with a |
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306 | * BE32 size header. |
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307 | * |
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308 | * @param out buffer where the hints are written |
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309 | * @param data buffer containing RTP packets |
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310 | * @param size the size of the data buffer |
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311 | * @param trk the MOVTrack for the hint track |
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312 | * @param dts pointer where the timestamp for the written RTP hint is stored |
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313 | * @return the number of RTP packets in the written hint |
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314 | */ |
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315 | static int write_hint_packets(AVIOContext *out, const uint8_t *data, |
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316 | int size, MOVTrack *trk, int64_t *dts) |
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317 | { |
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318 | int64_t curpos; |
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319 | int64_t count_pos, entries_pos; |
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320 | int count = 0, entries; |
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321 | |||
322 | count_pos = avio_tell(out); |
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323 | /* RTPsample header */ |
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324 | avio_wb16(out, 0); /* packet count */ |
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325 | avio_wb16(out, 0); /* reserved */ |
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326 | |||
327 | while (size > 4) { |
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328 | uint32_t packet_len = AV_RB32(data); |
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329 | uint16_t seq; |
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330 | uint32_t ts; |
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331 | int32_t ts_diff; |
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332 | |||
333 | data += 4; |
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334 | size -= 4; |
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335 | if (packet_len > size || packet_len <= 12) |
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336 | break; |
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337 | if (RTP_PT_IS_RTCP(data[1])) { |
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338 | /* RTCP packet, just skip */ |
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339 | data += packet_len; |
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340 | size -= packet_len; |
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341 | continue; |
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342 | } |
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343 | |||
344 | if (packet_len > trk->max_packet_size) |
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345 | trk->max_packet_size = packet_len; |
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346 | |||
347 | seq = AV_RB16(&data[2]); |
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348 | ts = AV_RB32(&data[4]); |
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349 | |||
350 | if (trk->prev_rtp_ts == 0) |
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351 | trk->prev_rtp_ts = ts; |
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352 | /* Unwrap the 32-bit RTP timestamp that wraps around often |
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353 | * into a not (as often) wrapping 64-bit timestamp. */ |
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354 | ts_diff = ts - trk->prev_rtp_ts; |
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355 | if (ts_diff > 0) { |
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356 | trk->cur_rtp_ts_unwrapped += ts_diff; |
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357 | trk->prev_rtp_ts = ts; |
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358 | ts_diff = 0; |
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359 | } |
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360 | if (*dts == AV_NOPTS_VALUE) |
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361 | *dts = trk->cur_rtp_ts_unwrapped; |
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362 | |||
363 | count++; |
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364 | /* RTPpacket header */ |
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365 | avio_wb32(out, 0); /* relative_time */ |
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366 | avio_write(out, data, 2); /* RTP header */ |
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367 | avio_wb16(out, seq); /* RTPsequenceseed */ |
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368 | avio_wb16(out, ts_diff ? 4 : 0); /* reserved + flags (extra_flag) */ |
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369 | entries_pos = avio_tell(out); |
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370 | avio_wb16(out, 0); /* entry count */ |
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371 | if (ts_diff) { /* if extra_flag is set */ |
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372 | avio_wb32(out, 16); /* extra_information_length */ |
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373 | avio_wb32(out, 12); /* rtpoffsetTLV box */ |
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374 | avio_write(out, "rtpo", 4); |
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375 | avio_wb32(out, ts_diff); |
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376 | } |
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377 | |||
378 | data += 12; |
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379 | size -= 12; |
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380 | packet_len -= 12; |
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381 | |||
382 | entries = 0; |
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383 | /* Write one or more constructors describing the payload data */ |
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384 | describe_payload(data, packet_len, out, &entries, &trk->sample_queue); |
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385 | data += packet_len; |
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386 | size -= packet_len; |
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387 | |||
388 | curpos = avio_tell(out); |
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389 | avio_seek(out, entries_pos, SEEK_SET); |
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390 | avio_wb16(out, entries); |
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391 | avio_seek(out, curpos, SEEK_SET); |
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392 | } |
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393 | |||
394 | curpos = avio_tell(out); |
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395 | avio_seek(out, count_pos, SEEK_SET); |
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396 | avio_wb16(out, count); |
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397 | avio_seek(out, curpos, SEEK_SET); |
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398 | return count; |
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399 | } |
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400 | |||
401 | int ff_mov_add_hinted_packet(AVFormatContext *s, AVPacket *pkt, |
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402 | int track_index, int sample, |
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403 | uint8_t *sample_data, int sample_size) |
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404 | { |
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405 | MOVMuxContext *mov = s->priv_data; |
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406 | MOVTrack *trk = &mov->tracks[track_index]; |
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407 | AVFormatContext *rtp_ctx = trk->rtp_ctx; |
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408 | uint8_t *buf = NULL; |
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409 | int size; |
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410 | AVIOContext *hintbuf = NULL; |
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411 | AVPacket hint_pkt; |
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412 | int ret = 0, count; |
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413 | |||
414 | if (!rtp_ctx) |
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415 | return AVERROR(ENOENT); |
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416 | if (!rtp_ctx->pb) |
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417 | return AVERROR(ENOMEM); |
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418 | |||
419 | if (sample_data) |
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420 | sample_queue_push(&trk->sample_queue, sample_data, sample_size, sample); |
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421 | else |
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422 | sample_queue_push(&trk->sample_queue, pkt->data, pkt->size, sample); |
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423 | |||
424 | /* Feed the packet to the RTP muxer */ |
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425 | ff_write_chained(rtp_ctx, 0, pkt, s); |
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426 | |||
427 | /* Fetch the output from the RTP muxer, open a new output buffer |
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428 | * for next time. */ |
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429 | size = avio_close_dyn_buf(rtp_ctx->pb, &buf); |
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430 | if ((ret = ffio_open_dyn_packet_buf(&rtp_ctx->pb, |
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431 | RTP_MAX_PACKET_SIZE)) < 0) |
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432 | goto done; |
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433 | |||
434 | if (size <= 0) |
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435 | goto done; |
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436 | |||
437 | /* Open a buffer for writing the hint */ |
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438 | if ((ret = avio_open_dyn_buf(&hintbuf)) < 0) |
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439 | goto done; |
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440 | av_init_packet(&hint_pkt); |
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441 | count = write_hint_packets(hintbuf, buf, size, trk, &hint_pkt.dts); |
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442 | av_freep(&buf); |
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443 | |||
444 | /* Write the hint data into the hint track */ |
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445 | hint_pkt.size = size = avio_close_dyn_buf(hintbuf, &buf); |
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446 | hint_pkt.data = buf; |
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447 | hint_pkt.pts = hint_pkt.dts; |
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448 | hint_pkt.stream_index = track_index; |
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449 | if (pkt->flags & AV_PKT_FLAG_KEY) |
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450 | hint_pkt.flags |= AV_PKT_FLAG_KEY; |
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451 | if (count > 0) |
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452 | ff_mov_write_packet(s, &hint_pkt); |
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453 | done: |
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454 | av_free(buf); |
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455 | sample_queue_retain(&trk->sample_queue); |
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456 | return ret; |
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457 | } |
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458 | |||
459 | void ff_mov_close_hinting(MOVTrack *track) |
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460 | { |
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461 | AVFormatContext *rtp_ctx = track->rtp_ctx; |
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462 | uint8_t *ptr; |
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463 | |||
464 | av_freep(&track->enc); |
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465 | sample_queue_free(&track->sample_queue); |
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466 | if (!rtp_ctx) |
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467 | return; |
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468 | if (rtp_ctx->pb) { |
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469 | av_write_trailer(rtp_ctx); |
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470 | avio_close_dyn_buf(rtp_ctx->pb, &ptr); |
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471 | av_free(ptr); |
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472 | } |
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473 | avformat_free_context(rtp_ctx); |
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474 | }>=>>=>>>>>=>=>>>>>>=>>=>> |