7 #include <netinet/in.h>
11 #include <sys/types.h>
18 #include "metacube2.h"
25 Stream::Stream(const string &url,
27 uint64_t prebuffering_bytes,
29 Encoding src_encoding,
30 unsigned hls_frag_duration,
31 size_t hls_backlog_margin,
32 const std::string &allow_origin)
35 src_encoding(src_encoding),
36 allow_origin(allow_origin),
37 data_fd(make_tempfile("")),
38 backlog_size(backlog_size),
39 prebuffering_bytes(prebuffering_bytes),
40 hls_frag_duration(hls_frag_duration),
41 hls_backlog_margin(hls_backlog_margin)
55 Stream::Stream(const StreamProto &serialized, int data_fd)
56 : url(serialized.url()),
57 unavailable(serialized.unavailable()),
58 http_header(serialized.http_header()),
59 stream_header(serialized.stream_header()),
60 encoding(Stream::STREAM_ENCODING_RAW), // Will be changed later.
62 backlog_size(serialized.backlog_size()),
63 bytes_received(serialized.bytes_received()),
64 first_fragment_index(serialized.first_fragment_index()),
65 discontinuity_counter(serialized.discontinuity_counter())
71 // Set the close-on-exec parameter back on the backlog fd.
72 fcntl(data_fd, F_SETFD, FD_CLOEXEC);
74 for (ssize_t point : serialized.suitable_starting_point()) {
76 // Can happen when upgrading from before 1.1.3,
77 // where this was an optional field with -1 signifying
81 suitable_starting_points.push_back(point);
84 for (const FragmentStartProto &fragment : serialized.fragment()) {
85 fragments.push_back(FragmentStart { size_t(fragment.byte_position()), fragment.pts(), fragment.begins_header() });
89 StreamProto Stream::serialize()
91 StreamProto serialized;
92 serialized.set_unavailable(unavailable);
93 serialized.set_http_header(http_header);
94 serialized.set_stream_header(stream_header);
95 serialized.add_data_fds(data_fd);
96 serialized.set_backlog_size(backlog_size);
97 serialized.set_bytes_received(bytes_received);
98 for (size_t point : suitable_starting_points) {
99 serialized.add_suitable_starting_point(point);
101 for (const FragmentStart &fragment : fragments) {
102 FragmentStartProto *proto = serialized.add_fragment();
103 proto->set_byte_position(fragment.byte_position);
104 proto->set_pts(fragment.pts);
105 proto->set_begins_header(fragment.begins_header);
107 serialized.set_first_fragment_index(first_fragment_index);
108 serialized.set_discontinuity_counter(discontinuity_counter);
110 // Unset the close-on-exec flag for the backlog fd.
111 // (This can't leak into a child, since there's only one thread left.)
112 fcntl(data_fd, F_SETFD, 0);
114 serialized.set_url(url);
119 void Stream::set_backlog_size(size_t new_size)
121 if (backlog_size == new_size) {
125 string existing_data;
126 if (!read_tempfile_and_close(data_fd, &existing_data)) {
130 // Unwrap the data so it's no longer circular.
131 if (bytes_received <= backlog_size) {
132 existing_data.resize(bytes_received);
134 size_t pos = bytes_received % backlog_size;
135 existing_data = existing_data.substr(pos, string::npos) +
136 existing_data.substr(0, pos);
139 // See if we need to discard data.
140 if (new_size < existing_data.size()) {
141 size_t to_discard = existing_data.size() - new_size;
142 existing_data = existing_data.substr(to_discard, string::npos);
145 // Create a new, empty data file.
146 data_fd = make_tempfile("");
150 backlog_size = new_size;
152 // Now cheat a bit by rewinding, and adding all the old data back.
153 bytes_received -= existing_data.size();
154 DataElement data_element;
155 data_element.data.iov_base = const_cast<char *>(existing_data.data());
156 data_element.data.iov_len = existing_data.size();
157 data_element.metacube_flags = 0; // Ignored by add_data_raw().
159 vector<DataElement> data_elements;
160 data_elements.push_back(data_element);
161 add_data_raw(data_elements);
162 remove_obsolete_starting_points();
165 void Stream::set_header(const std::string &new_http_header, const std::string &new_stream_header)
168 http_header = new_http_header;
169 if (new_stream_header == stream_header) {
173 // We cannot start at any of the older starting points anymore,
174 // since they'd get the wrong header for the stream (not to mention
175 // that a changed header probably means the stream restarted,
176 // which means any client starting on the old one would probably
177 // stop playing properly at the change point). Next block
178 // should be a suitable starting point (if not, something is
179 // pretty strange), so it will fill up again soon enough.
180 suitable_starting_points.clear();
182 // HLS, on the other hand, can deal with discontinuities and multiple
183 // headers. At least in theory (client support varies wildly).
184 if (!fragments.empty()) {
185 // Commit the old header to the backlog, so that we can serve it
186 // for all the old fragments for as long as they exist.
187 if (!stream_header.empty()) {
188 // End the current fragment and make a new one for the header.
189 fragments.push_back(Stream::FragmentStart { bytes_received, 0.0, true });
190 process_queued_data();
191 Stream::DataElement elem;
192 elem.data.iov_base = (char *)stream_header.data();
193 elem.data.iov_len = stream_header.size();
194 add_data_raw({ elem });
195 remove_obsolete_starting_points();
197 // The discontinuity counter will be increased when
198 // this header goes out of the backlog.
200 clear_hls_playlist_cache();
202 stream_header = new_stream_header;
205 void Stream::put_client_to_sleep(Client *client)
207 sleeping_clients.push_back(client);
210 // Return a new set of iovecs that contains only the first <bytes_wanted> bytes of <data>.
211 vector<iovec> collect_iovecs(const vector<Stream::DataElement> &data, size_t bytes_wanted)
214 size_t max_iovecs = min<size_t>(data.size(), IOV_MAX);
215 for (size_t i = 0; i < max_iovecs && bytes_wanted > 0; ++i) {
216 if (data[i].data.iov_len <= bytes_wanted) {
217 // Consume the entire iovec.
218 ret.push_back(data[i].data);
219 bytes_wanted -= data[i].data.iov_len;
221 // Take only parts of this iovec.
223 iov.iov_base = data[i].data.iov_base;
224 iov.iov_len = bytes_wanted;
232 // Return a new set of iovecs that contains all of <data> except the first <bytes_wanted> bytes.
233 vector<Stream::DataElement> remove_iovecs(const vector<Stream::DataElement> &data, size_t bytes_wanted)
235 vector<Stream::DataElement> ret;
237 for (i = 0; i < data.size() && bytes_wanted > 0; ++i) {
238 if (data[i].data.iov_len <= bytes_wanted) {
239 // Consume the entire iovec.
240 bytes_wanted -= data[i].data.iov_len;
242 // Take only parts of this iovec.
243 Stream::DataElement data_element;
244 data_element.data.iov_base = reinterpret_cast<char *>(data[i].data.iov_base) + bytes_wanted;
245 data_element.data.iov_len = data[i].data.iov_len - bytes_wanted;
246 data_element.metacube_flags = METACUBE_FLAGS_NOT_SUITABLE_FOR_STREAM_START;
247 data_element.pts = RationalPTS();
248 ret.push_back(data_element);
253 // Add the rest of the iovecs unchanged.
254 ret.insert(ret.end(), data.begin() + i, data.end());
258 void Stream::add_data_raw(const vector<DataElement> &orig_data)
260 vector<DataElement> data = orig_data;
261 while (!data.empty()) {
262 size_t pos = bytes_received % backlog_size;
264 // Collect as many iovecs as we can before we hit the point
265 // where the circular buffer wraps around.
266 vector<iovec> to_write = collect_iovecs(data, backlog_size - pos);
269 ret = pwritev(data_fd, to_write.data(), to_write.size(), pos);
270 } while (ret == -1 && errno == EINTR);
273 log_perror("pwritev");
274 // Dazed and confused, but trying to continue...
277 bytes_received += ret;
279 // Remove the data that was actually written from the set of iovecs.
280 data = remove_iovecs(data, ret);
284 void Stream::remove_obsolete_starting_points()
286 // We could do a binary search here (std::lower_bound), but it seems
287 // overkill for removing what's probably only a few points.
288 while (!suitable_starting_points.empty() &&
289 bytes_received - suitable_starting_points[0] > backlog_size) {
290 suitable_starting_points.pop_front();
292 assert(backlog_size >= hls_backlog_margin);
293 while (!fragments.empty() &&
294 bytes_received - fragments[0].byte_position > (backlog_size - hls_backlog_margin)) {
295 if (fragments[0].begins_header) {
296 ++discontinuity_counter;
298 ++first_fragment_index;
300 fragments.pop_front();
301 clear_hls_playlist_cache();
305 void Stream::add_data_deferred(const char *data, size_t bytes, uint16_t metacube_flags, const RationalPTS &pts)
307 // For regular output, we don't want to send the client twice
308 // (it's already sent out together with the HTTP header).
309 // However, for Metacube output, we need to send it so that
310 // the Cubemap instance in the other end has a chance to update it.
311 // It may come twice in its stream, but Cubemap doesn't care.
312 if (encoding == Stream::STREAM_ENCODING_RAW &&
313 (metacube_flags & METACUBE_FLAGS_HEADER) != 0) {
317 lock_guard<mutex> lock(queued_data_mutex);
319 DataElement data_element;
320 data_element.metacube_flags = metacube_flags;
321 data_element.pts = pts;
323 if (encoding == Stream::STREAM_ENCODING_METACUBE) {
324 // Construct a PTS metadata block. (We'll avoid sending it out
325 // if we don't have a valid PTS.)
326 metacube2_pts_packet pts_packet;
327 pts_packet.type = htobe64(METACUBE_METADATA_TYPE_NEXT_BLOCK_PTS);
328 pts_packet.pts = htobe64(pts.pts);
329 pts_packet.timebase_num = htobe64(pts.timebase_num);
330 pts_packet.timebase_den = htobe64(pts.timebase_den);
332 metacube2_block_header pts_hdr;
333 memcpy(pts_hdr.sync, METACUBE2_SYNC, sizeof(pts_hdr.sync));
334 pts_hdr.size = htonl(sizeof(pts_packet));
335 pts_hdr.flags = htons(METACUBE_FLAGS_METADATA);
336 pts_hdr.csum = htons(metacube2_compute_crc(&pts_hdr));
338 // Add a Metacube block header before the data.
339 metacube2_block_header hdr;
340 memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
341 hdr.size = htonl(bytes);
342 hdr.flags = htons(metacube_flags);
343 hdr.csum = htons(metacube2_compute_crc(&hdr));
345 data_element.data.iov_len = bytes + sizeof(hdr);
346 if (pts.timebase_num != 0) {
347 data_element.data.iov_len += sizeof(pts_hdr) + sizeof(pts_packet);
349 data_element.data.iov_base = new char[data_element.data.iov_len];
351 char *ptr = reinterpret_cast<char *>(data_element.data.iov_base);
352 if (pts.timebase_num != 0) {
353 memcpy(ptr, &pts_hdr, sizeof(pts_hdr));
354 ptr += sizeof(pts_hdr);
355 memcpy(ptr, &pts_packet, sizeof(pts_packet));
356 ptr += sizeof(pts_packet);
359 memcpy(ptr, &hdr, sizeof(hdr));
361 memcpy(ptr, data, bytes);
363 queued_data.push_back(data_element);
364 } else if (encoding == Stream::STREAM_ENCODING_RAW) {
365 // Just add the data itself.
366 data_element.data.iov_base = new char[bytes];
367 memcpy(data_element.data.iov_base, data, bytes);
368 data_element.data.iov_len = bytes;
370 queued_data.push_back(data_element);
376 void Stream::process_queued_data()
378 vector<DataElement> queued_data_copy;
380 // Hold the lock for as short as possible, since add_data_raw() can possibly
381 // write to disk, which might disturb the input thread.
383 lock_guard<mutex> lock(queued_data_mutex);
384 if (queued_data.empty()) {
388 swap(queued_data, queued_data_copy);
391 // Add suitable starting points for the stream, if the queued data
392 // contains such starting points. Note that we drop starting points
393 // if they're less than 10 kB apart, so that we don't get a huge
394 // amount of them for e.g. each and every MPEG-TS 188-byte cell.
395 // The 10 kB value is somewhat arbitrary, but at least it should make
396 // the RAM cost of saving the position ~0.1% (or less) of the actual
397 // data, and 10 kB is a very fine granularity in most streams.
398 static const int minimum_start_point_distance = 10240;
399 size_t byte_position = bytes_received;
400 bool need_hls_clear = false;
401 for (const DataElement &elem : queued_data_copy) {
402 if ((elem.metacube_flags & METACUBE_FLAGS_NOT_SUITABLE_FOR_STREAM_START) == 0) {
403 size_t num_points = suitable_starting_points.size();
404 if (num_points >= 2 &&
405 suitable_starting_points[num_points - 1] - suitable_starting_points[num_points - 2] < minimum_start_point_distance) {
406 // p[n-1] - p[n-2] < 10 kB, so drop p[n-1].
407 suitable_starting_points.pop_back();
409 suitable_starting_points.push_back(byte_position);
411 if (elem.pts.timebase_num != 0) {
412 need_hls_clear |= add_fragment_boundary(byte_position, elem.pts);
415 byte_position += elem.data.iov_len;
417 if (need_hls_clear) {
418 clear_hls_playlist_cache();
421 add_data_raw(queued_data_copy);
422 remove_obsolete_starting_points();
423 for (const DataElement &elem : queued_data_copy) {
424 char *data = reinterpret_cast<char *>(elem.data.iov_base);
428 // We have more data, so wake up all clients.
429 if (to_process.empty()) {
430 swap(sleeping_clients, to_process);
432 to_process.insert(to_process.end(), sleeping_clients.begin(), sleeping_clients.end());
433 sleeping_clients.clear();
437 bool Stream::add_fragment_boundary(size_t byte_position, const RationalPTS &pts)
439 double pts_double = double(pts.pts) * pts.timebase_den / pts.timebase_num;
441 if (fragments.size() <= 1 ||
442 fragments[fragments.size() - 1].begins_header ||
443 fragments[fragments.size() - 2].begins_header) {
444 // Just starting up, so try to establish the first in-progress fragment.
445 fragments.push_back(FragmentStart{ byte_position, pts_double, false });
449 // Keep extending the in-progress fragment as long as we do not
450 // exceed the target duration by more than half a second
451 // (RFC 8216 4.3.3.1) and we get closer to the target by doing so.
452 // Note that in particular, this means we'll always extend
453 // as long as we don't exceed the target duration.
454 double current_duration = pts_double - fragments[fragments.size() - 1].pts;
455 double candidate_duration = pts_double - fragments[fragments.size() - 2].pts;
456 if (lrintf(candidate_duration) <= hls_frag_duration &&
457 fabs(candidate_duration - hls_frag_duration) < fabs(current_duration - hls_frag_duration)) {
458 fragments.back() = FragmentStart{ byte_position, pts_double, false };
461 // Extending the in-progress fragment would make it too long,
462 // so finalize it and start a new in-progress fragment.
463 fragments.push_back(FragmentStart{ byte_position, pts_double, false });
468 void Stream::clear_hls_playlist_cache()
470 hls_playlist_http10.reset();
471 hls_playlist_http11_close.reset();
472 hls_playlist_http11_persistent.reset();
475 shared_ptr<const string> Stream::generate_hls_playlist(bool http_11, bool close_after_response)
478 snprintf(buf, sizeof(buf),
480 "#EXT-X-VERSION:7\r\n"
481 "#EXT-X-TARGETDURATION:%u\r\n"
482 "#EXT-X-MEDIA-SEQUENCE:%" PRIu64 "\r\n"
483 "#EXT-X-DISCONTINUITY-SEQUENCE:%" PRIu64 "\r\n",
485 first_fragment_index,
486 discontinuity_counter);
488 string playlist = buf;
490 if (fragments.size() >= 3) {
491 bool printed_header_for_this_group = false;
492 bool printed_first_header = false;
493 for (size_t i = 0; i < fragments.size() - 2; ++i) {
496 if (fragments[i].begins_header) {
497 // End of this group. (We've already printed the header
498 // as part of the previous group.)
499 printed_header_for_this_group = false;
502 if (!printed_header_for_this_group) {
503 // Look forward until we find the header for this group (if any).
504 for (size_t j = i + 1; j < fragments.size() - 1; ++j) {
505 if (fragments[j].begins_header) {
506 if (printed_first_header) {
507 playlist += "#EXT-X-DISCONTINUITY\r\n";
509 snprintf(buf, sizeof(buf),
510 "#EXT-X-MAP:URI=\"%s?frag=%" PRIu64 "-%" PRIu64 "\"\r\n",
511 url.c_str(), fragments[j].byte_position,
512 fragments[j + 1].byte_position);
514 printed_first_header = true;
515 printed_header_for_this_group = true;
520 if (!printed_header_for_this_group && !stream_header.empty()) {
521 if (printed_first_header) {
522 playlist += "#EXT-X-DISCONTINUITY\r\n";
524 snprintf(buf, sizeof(buf), "#EXT-X-MAP:URI=\"%s?frag=header\"\r\n", url.c_str());
528 // Even if we didn't find anything, we don't want to search again for each fragment.
529 printed_first_header = true;
530 printed_header_for_this_group = true;
533 if (fragments[i + 1].begins_header) {
534 // Since we only have start pts for each block and not duration,
535 // we have no idea how long this fragment is; the encoder restarted
536 // before it got to output the next pts. However, it's likely
537 // to be very short, so instead of trying to guess, we just skip it.
541 snprintf(buf, sizeof(buf), "#EXTINF:%f,\r\n%s?frag=%" PRIu64 "-%" PRIu64 "\r\n",
542 fragments[i + 1].pts - fragments[i].pts,
544 fragments[i].byte_position,
545 fragments[i + 1].byte_position);
552 response = "HTTP/1.1 200 OK\r\n";
553 if (close_after_response) {
554 response.append("Connection: close\r\n");
557 assert(close_after_response);
558 response = "HTTP/1.0 200 OK\r\n";
560 snprintf(buf, sizeof(buf), "Content-Length: %zu\r\n", playlist.size());
561 response.append(buf);
562 response.append("Content-Type: application/x-mpegURL\r\n");
563 if (!allow_origin.empty()) {
564 response.append("Access-Control-Allow-Origin: ");
565 response.append(allow_origin);
566 response.append("\r\n");
568 response.append("\r\n");
569 response.append(move(playlist));
571 return shared_ptr<const string>(new string(move(response)));