]> git.sesse.net Git - cubemap/blobdiff - stream.cpp
Fix a crash when trying to get HLS fragments from a disconnected strema.
[cubemap] / stream.cpp
index f5abbfd0f3e07795a0502c3d562ec56a01d3a5f4..3ee1a434d2e6fe6c3cc73fcc84d89d860efd0f05 100644 (file)
@@ -1,6 +1,8 @@
 #include <assert.h>
 #include <errno.h>
+#include <inttypes.h>
 #include <limits.h>
+#include <math.h>
 #include <netinet/in.h>
 #include <stdio.h>
 #include <stdlib.h>
 
 #include "log.h"
 #include "metacube2.h"
-#include "mutexlock.h"
 #include "state.pb.h"
 #include "stream.h"
 #include "util.h"
 
 using namespace std;
 
-Stream::Stream(const string &url, size_t backlog_size, size_t prebuffering_bytes, Encoding encoding, Encoding src_encoding)
+Stream::Stream(const string &url,
+               size_t backlog_size,
+               uint64_t prebuffering_bytes,
+               Encoding encoding,
+               Encoding src_encoding,
+               unsigned hls_frag_duration,
+               size_t hls_backlog_margin,
+               const std::string &allow_origin)
        : url(url),
          encoding(encoding),
          src_encoding(src_encoding),
+         allow_origin(allow_origin),
          data_fd(make_tempfile("")),
-          backlog_size(backlog_size),
+         backlog_size(backlog_size),
          prebuffering_bytes(prebuffering_bytes),
-         bytes_received(0),
-         pacing_rate(~0U)
+         hls_frag_duration(hls_frag_duration),
+         hls_backlog_margin(hls_backlog_margin)
 {
        if (data_fd == -1) {
                exit(1);
        }
-
-       pthread_mutex_init(&queued_data_mutex, nullptr);
 }
 
 Stream::~Stream()
@@ -46,14 +53,15 @@ Stream::~Stream()
 
 Stream::Stream(const StreamProto &serialized, int data_fd)
        : url(serialized.url()),
+         unavailable(serialized.unavailable()),
          http_header(serialized.http_header()),
          stream_header(serialized.stream_header()),
          encoding(Stream::STREAM_ENCODING_RAW),  // Will be changed later.
          data_fd(data_fd),
          backlog_size(serialized.backlog_size()),
-         prebuffering_bytes(serialized.prebuffering_bytes()),
          bytes_received(serialized.bytes_received()),
-         pacing_rate(~0U)
+         first_fragment_index(serialized.first_fragment_index()),
+         discontinuity_counter(serialized.discontinuity_counter())
 {
        if (data_fd == -1) {
                exit(1);
@@ -69,21 +77,32 @@ Stream::Stream(const StreamProto &serialized, int data_fd)
                suitable_starting_points.push_back(point);
        }
 
-       pthread_mutex_init(&queued_data_mutex, nullptr);
+       for (const FragmentStartProto &fragment : serialized.fragment()) {
+               fragments.push_back(FragmentStart { size_t(fragment.byte_position()), fragment.pts(), fragment.begins_header() });
+       }
 }
 
 StreamProto Stream::serialize()
 {
        StreamProto serialized;
+       serialized.set_unavailable(unavailable);
        serialized.set_http_header(http_header);
        serialized.set_stream_header(stream_header);
        serialized.add_data_fds(data_fd);
        serialized.set_backlog_size(backlog_size);
-       serialized.set_prebuffering_bytes(prebuffering_bytes);
        serialized.set_bytes_received(bytes_received);
        for (size_t point : suitable_starting_points) {
                serialized.add_suitable_starting_point(point);
        }
+       for (const FragmentStart &fragment : fragments) {
+               FragmentStartProto *proto = serialized.add_fragment();
+               proto->set_byte_position(fragment.byte_position);
+               proto->set_pts(fragment.pts);
+               proto->set_begins_header(fragment.begins_header);
+       }
+       serialized.set_first_fragment_index(first_fragment_index);
+       serialized.set_discontinuity_counter(discontinuity_counter);
+
        serialized.set_url(url);
        data_fd = -1;
        return serialized;
@@ -135,6 +154,46 @@ void Stream::set_backlog_size(size_t new_size)
        remove_obsolete_starting_points();
 }
 
+void Stream::set_header(const std::string &new_http_header, const std::string &new_stream_header)
+{
+       unavailable = false;
+       http_header = new_http_header;
+       if (new_stream_header == stream_header) {
+               return;
+       }
+
+       // We cannot start at any of the older starting points anymore,
+       // since they'd get the wrong header for the stream (not to mention
+       // that a changed header probably means the stream restarted,
+       // which means any client starting on the old one would probably
+       // stop playing properly at the change point). Next block
+       // should be a suitable starting point (if not, something is
+       // pretty strange), so it will fill up again soon enough.
+       suitable_starting_points.clear();
+
+       // HLS, on the other hand, can deal with discontinuities and multiple
+       // headers. At least in theory (client support varies wildly).
+       if (!fragments.empty()) {
+               // Commit the old header to the backlog, so that we can serve it
+               // for all the old fragments for as long as they exist.
+               if (!stream_header.empty()) {
+                       // End the current fragment and make a new one for the header.
+                       fragments.push_back(Stream::FragmentStart { bytes_received, 0.0, true });
+                       process_queued_data();
+                       Stream::DataElement elem;
+                       elem.data.iov_base = (char *)stream_header.data();
+                       elem.data.iov_len = stream_header.size();
+                       add_data_raw({ elem });
+                       remove_obsolete_starting_points();
+
+                       // The discontinuity counter will be increased when
+                       // this header goes out of the backlog.
+               }
+               clear_hls_playlist_cache();
+       }
+       stream_header = new_stream_header;
+}
+
 void Stream::put_client_to_sleep(Client *client)
 {
        sleeping_clients.push_back(client);
@@ -177,6 +236,7 @@ vector<Stream::DataElement> remove_iovecs(const vector<Stream::DataElement> &dat
                        data_element.data.iov_base = reinterpret_cast<char *>(data[i].data.iov_base) + bytes_wanted;
                        data_element.data.iov_len = data[i].data.iov_len - bytes_wanted;
                        data_element.metacube_flags = METACUBE_FLAGS_NOT_SUITABLE_FOR_STREAM_START;
+                       data_element.pts = RationalPTS();
                        ret.push_back(data_element);
                        bytes_wanted = 0;
                }
@@ -221,9 +281,20 @@ void Stream::remove_obsolete_starting_points()
               bytes_received - suitable_starting_points[0] > backlog_size) {
                suitable_starting_points.pop_front();
        }
+       assert(backlog_size >= hls_backlog_margin);
+       while (!fragments.empty() &&
+              bytes_received - fragments[0].byte_position > (backlog_size - hls_backlog_margin)) {
+               if (fragments[0].begins_header) {
+                       ++discontinuity_counter;
+               } else {
+                       ++first_fragment_index;
+               }
+               fragments.pop_front();
+               clear_hls_playlist_cache();
+       }
 }
 
-void Stream::add_data_deferred(const char *data, size_t bytes, uint16_t metacube_flags)
+void Stream::add_data_deferred(const char *data, size_t bytes, uint16_t metacube_flags, const RationalPTS &pts)
 {
        // For regular output, we don't want to send the client twice
        // (it's already sent out together with the HTTP header).
@@ -235,12 +306,27 @@ void Stream::add_data_deferred(const char *data, size_t bytes, uint16_t metacube
                return;
        }
 
-       MutexLock lock(&queued_data_mutex);
+       lock_guard<mutex> lock(queued_data_mutex);
 
        DataElement data_element;
        data_element.metacube_flags = metacube_flags;
+       data_element.pts = pts;
 
        if (encoding == Stream::STREAM_ENCODING_METACUBE) {
+               // Construct a PTS metadata block. (We'll avoid sending it out
+               // if we don't have a valid PTS.)
+               metacube2_pts_packet pts_packet;
+               pts_packet.type = htobe64(METACUBE_METADATA_TYPE_NEXT_BLOCK_PTS);
+               pts_packet.pts = htobe64(pts.pts);
+               pts_packet.timebase_num = htobe64(pts.timebase_num);
+               pts_packet.timebase_den = htobe64(pts.timebase_den);
+
+               metacube2_block_header pts_hdr;
+               memcpy(pts_hdr.sync, METACUBE2_SYNC, sizeof(pts_hdr.sync));
+               pts_hdr.size = htonl(sizeof(pts_packet));
+               pts_hdr.flags = htons(METACUBE_FLAGS_METADATA);
+               pts_hdr.csum = htons(metacube2_compute_crc(&pts_hdr));
+
                // Add a Metacube block header before the data.
                metacube2_block_header hdr;
                memcpy(hdr.sync, METACUBE2_SYNC, sizeof(hdr.sync));
@@ -248,11 +334,23 @@ void Stream::add_data_deferred(const char *data, size_t bytes, uint16_t metacube
                hdr.flags = htons(metacube_flags);
                hdr.csum = htons(metacube2_compute_crc(&hdr));
 
-               data_element.data.iov_base = new char[bytes + sizeof(hdr)];
                data_element.data.iov_len = bytes + sizeof(hdr);
+               if (pts.timebase_num != 0) {
+                       data_element.data.iov_len += sizeof(pts_hdr) + sizeof(pts_packet);
+               }
+               data_element.data.iov_base = new char[data_element.data.iov_len];
+
+               char *ptr = reinterpret_cast<char *>(data_element.data.iov_base);
+               if (pts.timebase_num != 0) {
+                       memcpy(ptr, &pts_hdr, sizeof(pts_hdr));
+                       ptr += sizeof(pts_hdr);
+                       memcpy(ptr, &pts_packet, sizeof(pts_packet));
+                       ptr += sizeof(pts_packet);
+               }
 
-               memcpy(data_element.data.iov_base, &hdr, sizeof(hdr));
-               memcpy(reinterpret_cast<char *>(data_element.data.iov_base) + sizeof(hdr), data, bytes);
+               memcpy(ptr, &hdr, sizeof(hdr));
+               ptr += sizeof(hdr);
+               memcpy(ptr, data, bytes);
 
                queued_data.push_back(data_element);
        } else if (encoding == Stream::STREAM_ENCODING_RAW) {
@@ -274,7 +372,7 @@ void Stream::process_queued_data()
        // Hold the lock for as short as possible, since add_data_raw() can possibly
        // write to disk, which might disturb the input thread.
        {
-               MutexLock lock(&queued_data_mutex);
+               lock_guard<mutex> lock(queued_data_mutex);
                if (queued_data.empty()) {
                        return;
                }
@@ -291,6 +389,7 @@ void Stream::process_queued_data()
        // data, and 10 kB is a very fine granularity in most streams.
        static const int minimum_start_point_distance = 10240;
        size_t byte_position = bytes_received;
+       bool need_hls_clear = false;
        for (const DataElement &elem : queued_data_copy) {
                if ((elem.metacube_flags & METACUBE_FLAGS_NOT_SUITABLE_FOR_STREAM_START) == 0) {
                        size_t num_points = suitable_starting_points.size();
@@ -300,9 +399,16 @@ void Stream::process_queued_data()
                                suitable_starting_points.pop_back();
                        }
                        suitable_starting_points.push_back(byte_position);
+
+                       if (elem.pts.timebase_num != 0) {
+                               need_hls_clear |= add_fragment_boundary(byte_position, elem.pts);
+                       }
                }
                byte_position += elem.data.iov_len;
        }
+       if (need_hls_clear) {
+               clear_hls_playlist_cache();
+       }
 
        add_data_raw(queued_data_copy);
        remove_obsolete_starting_points();
@@ -319,3 +425,140 @@ void Stream::process_queued_data()
                sleeping_clients.clear();
        }
 }
+
+bool Stream::add_fragment_boundary(size_t byte_position, const RationalPTS &pts)
+{
+       double pts_double = double(pts.pts) * pts.timebase_den / pts.timebase_num;
+
+       if (fragments.size() <= 1 ||
+           fragments[fragments.size() - 1].begins_header ||
+           fragments[fragments.size() - 2].begins_header) {
+               // Just starting up, so try to establish the first in-progress fragment.
+               fragments.push_back(FragmentStart{ byte_position, pts_double, false });
+               return false;
+       }
+
+       // Keep extending the in-progress fragment as long as we do not
+       // exceed the target duration by more than half a second
+       // (RFC 8216 4.3.3.1) and we get closer to the target by doing so.
+       // Note that in particular, this means we'll always extend
+       // as long as we don't exceed the target duration.
+       double current_duration = pts_double - fragments[fragments.size() - 1].pts;
+       double candidate_duration = pts_double - fragments[fragments.size() - 2].pts;
+       if (lrintf(candidate_duration) <= hls_frag_duration &&
+           fabs(candidate_duration - hls_frag_duration) < fabs(current_duration - hls_frag_duration)) {
+               fragments.back() = FragmentStart{ byte_position, pts_double, false };
+               return false;
+       } else {
+               // Extending the in-progress fragment would make it too long,
+               // so finalize it and start a new in-progress fragment.
+               fragments.push_back(FragmentStart{ byte_position, pts_double, false });
+               return true;
+       }
+}
+
+void Stream::clear_hls_playlist_cache()
+{
+       hls_playlist_http10.reset();
+       hls_playlist_http11_close.reset();
+       hls_playlist_http11_persistent.reset();
+}
+
+shared_ptr<const string> Stream::generate_hls_playlist(bool http_11, bool close_after_response)
+{
+       char buf[256];
+       snprintf(buf, sizeof(buf),
+               "#EXTM3U\r\n"
+               "#EXT-X-VERSION:7\r\n"
+               "#EXT-X-TARGETDURATION:%u\r\n"
+               "#EXT-X-MEDIA-SEQUENCE:%" PRIu64 "\r\n"
+               "#EXT-X-DISCONTINUITY-SEQUENCE:%" PRIu64 "\r\n",
+               hls_frag_duration,
+               first_fragment_index,
+               discontinuity_counter);
+
+       string playlist = buf;
+
+       if (fragments.size() >= 3) {
+               bool printed_header_for_this_group = false;
+               bool printed_first_header = false;
+               for (size_t i = 0; i < fragments.size() - 2; ++i) {
+                       char buf[256];
+
+                       if (fragments[i].begins_header) {
+                               // End of this group. (We've already printed the header
+                               // as part of the previous group.)
+                               printed_header_for_this_group = false;
+                               continue;
+                       }
+                       if (!printed_header_for_this_group) {
+                               // Look forward until we find the header for this group (if any).
+                               for (size_t j = i + 1; j < fragments.size() - 1; ++j) {
+                                       if (fragments[j].begins_header) {
+                                               if (printed_first_header) {
+                                                       playlist += "#EXT-X-DISCONTINUITY\r\n";
+                                               }
+                                               snprintf(buf, sizeof(buf),
+                                                       "#EXT-X-MAP:URI=\"%s?frag=%" PRIu64 "-%" PRIu64 "\"\r\n",
+                                                       url.c_str(), fragments[j].byte_position,
+                                                       fragments[j + 1].byte_position);
+                                               playlist += buf;
+                                               printed_first_header = true;
+                                               printed_header_for_this_group = true;
+                                               break;
+                                       }
+                               }
+
+                               if (!printed_header_for_this_group && !stream_header.empty()) {
+                                       if (printed_first_header) {
+                                               playlist += "#EXT-X-DISCONTINUITY\r\n";
+                                       }
+                                       snprintf(buf, sizeof(buf), "#EXT-X-MAP:URI=\"%s?frag=header\"\r\n", url.c_str());
+                                       playlist += buf;
+                               }
+
+                               // Even if we didn't find anything, we don't want to search again for each fragment.
+                               printed_first_header = true;
+                               printed_header_for_this_group = true;
+                       }
+
+                       if (fragments[i + 1].begins_header) {
+                               // Since we only have start pts for each block and not duration,
+                               // we have no idea how long this fragment is; the encoder restarted
+                               // before it got to output the next pts. However, it's likely
+                               // to be very short, so instead of trying to guess, we just skip it.
+                               continue;
+                       }
+
+                       snprintf(buf, sizeof(buf), "#EXTINF:%f,\r\n%s?frag=%" PRIu64 "-%" PRIu64 "\r\n",
+                               fragments[i + 1].pts - fragments[i].pts,
+                               url.c_str(),
+                               fragments[i].byte_position,
+                               fragments[i + 1].byte_position);
+                       playlist += buf;
+               }
+       }
+
+       string response;
+       if (http_11) {
+               response = "HTTP/1.1 200 OK\r\n";
+               if (close_after_response) {
+                       response.append("Connection: close\r\n");
+               }
+       } else {
+               assert(close_after_response);
+               response = "HTTP/1.0 200 OK\r\n";
+       }
+       snprintf(buf, sizeof(buf), "Content-Length: %zu\r\n", playlist.size());
+       response.append(buf);
+       response.append("Content-Type: application/x-mpegURL\r\n");
+       if (!allow_origin.empty()) {
+               response.append("Access-Control-Allow-Origin: ");
+               response.append(allow_origin);
+               response.append("\r\n");
+       }
+       response.append("\r\n");
+       response.append(move(playlist));
+
+       return shared_ptr<const string>(new string(move(response)));
+}