Method ReadStream

src/FFmpegReader.cpp:1264–1466

Read the stream until we find the requested Frame

// Read the stream until we find the requested Frame
std::shared_ptr<Frame> FFmpegReader::ReadStream(int64_t requested_frame) {
	// Allocate video frame
	bool check_seek = false;
	int packet_error = -1;
	int64_t no_progress_count = 0;
	int64_t prev_packets_read = packet_status.packets_read();
	int64_t prev_packets_decoded = packet_status.packets_decoded();
	int64_t prev_video_decoded = packet_status.video_decoded;
	double prev_video_pts_seconds = video_pts_seconds;

	// Debug output
	ZmqLogger::Instance()->AppendDebugMethod("FFmpegReader::ReadStream", "requested_frame", requested_frame);

	// Loop through the stream until the correct frame is found
	while (true) {
		// Check if working frames are 'finished'
		if (!is_seeking) {
			// Check for final frames
			CheckWorkingFrames(requested_frame);
		}

		// Check if requested 'final' frame is available (and break out of loop if found)
		bool is_cache_found = (final_cache.GetFrame(requested_frame) != NULL);
		if (is_cache_found) {
			break;
		}

		if (!hold_packet || !packet) {
			// Get the next packet
			packet_error = GetNextPacket();
			if (packet_error < 0 && !packet) {
				// No more packets to be found
				packet_status.packets_eof = true;
			}
		}

		// Debug output
		ZmqLogger::Instance()->AppendDebugMethod("FFmpegReader::ReadStream (GetNextPacket)", "requested_frame", requested_frame,"packets_read", packet_status.packets_read(), "packets_decoded", packet_status.packets_decoded(), "is_seeking", is_seeking);

		// Check the status of a seek (if any)
		if (is_seeking) {
			check_seek = CheckSeek();
		} else {
			check_seek = false;
		}

		if (check_seek) {
			// Packet may become NULL on Close inside Seek if CheckSeek returns false
			// Jump to the next iteration of this loop
			continue;
		}

		// Video packet
		if ((info.has_video && packet && packet->stream_index == videoStream) ||
			(info.has_video && packet_status.video_decoded < packet_status.video_read) ||
			(info.has_video && !packet && !packet_status.video_eof)) {
			// Process Video Packet
			ProcessVideoPacket(requested_frame);