Applying suggestions on deleted lines is not supported. Check / uncheck the NTP checkbox to enable / disable Network Time Protocol. Oh wow thats exactly what I was looking for, could you please share what rosbag play argument you are talking about. In rosbag record, it's using asyncspinner w/ 10 threads, and it subscribes to many topics, all to the same callback doQueue, which when called, checks the current time, and adds the message + timestamp onto a queue. Here we are just making a temporary directory to record data and then running rosbag record with the option -a, indicating that all published topics should be accumulated in a bag file. You must change the existing code in this line in order to create a valid suggestion. The first/end data are: Subtracting these values I have 688 seconds = 11 minutes. and the However this means while writing messages out to disk, new messages can't be added on to the queue, so those threads will pause at the line of code that acquires the lock. While the message's std_msg/Header.stamp is the acquisition time, which can be a out of order and a bit sooner than the time in the bag header. Then, the received messages are dispatched to subscriber callbacks. In the window running rosbag record exit with a Ctrl-C. It's a simple 5-line program. Messages can then be added with sequential calls to record. I am also concerned about out of order messages, where messages have been acquired at different times, but they reach the bag file writing queue out of order. so for example, I can have a bag file with two consecutive messages, where. With that I get similar values but (I have reported the problem before) the first messages are skipped. If this is true, is there a way to force a rosbag to instead encode messages with the timestamp which were published with them? Some publishers backdate or future-date timestamps, which can cause them to differ from the actual time by a significant amount. Why do some airports shuffle connecting passengers through security again. Site design / logo 2022 Stack Exchange Inc; user contributions licensed under CC BY-SA. I am trying to get the timestamp for a particular ROS message, record it in a file, read the file and recover the original timestamp. How to change different topics pace in rosbag? Some publishers backdate or future-date timestamps, which can cause them to differ from the actual time by a significant amount. MATLAB can read these rosbag files and help with filtering and extracting message data. When the doRecord thread is busy closing the current file and opening the next one (I have no idea how long this might take), it can not pop items from the queue. Problem: When we are recording large volumes of data, we have it set to split to a new bag file every 30GB. Browse other questions tagged, Where developers & technologists share private knowledge with coworkers, Reach developers & technologists worldwide. The rosbag writers and readers do not look at the header timestamp within the messages, and does not guarantee that messages are ordered by those timestamps. When would I give a checkpoint to my D&D party that they can return to if they die? ROS and rosbag make no guarantees about the meaning, offset between these timestamps and rosbag timestamps, or even the timestamp validity. But assessing this data again. Is it cheating if the proctor gives a student the answer key by mistake and the student doesn't report it? Some tool makes the trick? The rosbag C++ API works on the premise of creating "views" of one or more bags using "queries". # /tf/tf_static $ rosbag record -e "/tf. Done, still need 10 points to accept my own answer though :/. And this is Not realistic because I have killed the simulation and the rosbag after 2 minutes( max) and the car in the simulation achieved the goal after 1 min, not 11 minutes Semantics of `%time` timestamp in `rostopic echo -p` from bagfile? Click Main Menu and then click the Setting icon ( ). header stamp and [closed], How to publish topic with old rosbag time? Connect and share knowledge within a single location that is structured and easy to search. I tried, but it looks like I don't have enough points to reopen my question. Please start posting anonymously - your entry will be published after you log in or create a new account. I'd argue, that the actual problem is a too small queue size or something similar. I want to use rosbag record in my launch file with the parameters linking to a ros package. It should also be pointed out (thanks to the comments from visitors to this site) that this point . Only one suggestion per line can be applied in a batch. By clicking Post Your Answer, you agree to our terms of service, privacy policy and cookie policy. How to use service calls to toggle rosbag? Since this is AFTER capturing the timestamp, you'd think this would be okbut the problem is we only have 10 threads handling callbacks, so if writing messages out to disk takes longer than the time for 10 messages to come in, the messages will be stuck on the internal ros queue BEFORE calling our callback, meaning the ros::Time::now call wont be called until later, getting a later timestamp. Suggestions cannot be applied from pending reviews. If I may suggest: please re-open the question, post your edit as an answer and accept your own answer. Suggestions cannot be applied while the pull request is closed. How can I use a VPN to access a Russian website that is banned in the EU? All of those things are the responsibility of the publisher. TouchDeeper Dec 27 '20 Your Answer If someone could help me, I would be very grateful, Beginning of csv file (localizer or odom topic), Hi @gvdhoorn has already assisted me on this, https://answers.ros.org/question/388683/convert-time-stamp-from-rosbagtopic-to-understandable-format-ymd-hms/?answer=388706#post-id-388706, Thanks and sorry to duplicate here header TimeStamp? The rosbag code API page includes an example of how to use the Python API to read messages out of a bag. Looking at the ROSbag.v2 specification, every message stored in a bag file is comprised of a: The header contains a connection ID and a TimeStamp. If the serialized message contains a timestamp, it is populated by the publisher of that message. Rosbag and timestamp received vs timestamp published, Creative Commons Attribution Share Alike 3.0. By clicking Accept all cookies, you agree Stack Exchange can store cookies on your device and disclose information in accordance with our Cookie Policy. The "bag" is a directory, a single db3 file is not a "bag", it is a storage backend file within a bag. How to get summit-xl-sim running in ROS melodic, Creative Commons Attribution Share Alike 3.0. import os import os.path import rosbag from sensor_msgs.msg import Image import rospy IMG_DIRNAME = '/the/root/to/bags/' #we get only one . that intuitively should return the seconds. Making statements based on opinion; back them up with references or personal experience. Click the Date&Time tab. privacy statement. (this is not the problem of this question), Here comes the weird part. In general, who is usually responsible of handling out of order messages? Is there any way to get roscore string using python script in raspberry pi? This count starts at the Unix Epoch on January 1st, 1970 at UTC. Find centralized, trusted content and collaborate around the technologies you use most. As the queue size is limited by buffer_size, increasing it might help. A Query is an abstract class which defines a function that filters whether or not the messages from a connection are to be included. Can virent/viret mean "green" in an adjectival sense? Get tf transform AFTER publishing node has died, colcon build failed for soss-ros1 in soss. Is energy "equal" to the curvature of spacetime? Mathematica cannot find square roots of some matrices? It can show the most accurate time now at any selected point on earth. These rosbags contain messages of type sensor_msgs/Image among other topics. Learn more about bidirectional Unicode characters, rosbag record: Increase subscriber queue size, rosbag recorder: Wait for valid time BEFORE subscribing, add a note that we're running a modified version of rosbag record. I've seen offsets up to 1/2 a second for properly functioning publishers, and I've seen other publishers that just set all timestamps to 0 because their clients don't need the timestamp at all. Therefore, the unix time stamp is merely the number of seconds between a particular date and the Unix Epoch. Normally, you can get a package path in a launch file by using $ {find mypackage}, but this does not work in this case, I presume because the $ {find pkg} command doesn't work in the args statement of the launch file (? Problem: When the bag file is complete, close it using close. You signed in with another tab or window. Or some Python Library such as DateTime (how to specific use, suitable class to apply? To spare the somewhat obscure details of the implementation, this problem essentially happens because rospy.rostime does not get initialized correctly when just playing a bag file and echoing that; even if you set /use_sim_time to true. But the actual message Header.stamps can be sooner and out of order. Not the answer you're looking for? Asking for help, clarification, or responding to other answers. It aquires the lock, pops the last item in the queue, releases the lock and then writes. Generally messages from a single publisher are written in the order that they are received, but if there are multiple publishers on a topic, you can easily get header timestamps slightly out order. Suggestions cannot be applied while the pull request is queued to merge. Ideally, you do not need to open individual files, instead you would use a rosbag2 Read API to open a whole bag, which can open files as necessary. A rosbag or bag is a file format in ROS for storing ROS message data. This is a known "issue" with rostopic echo and bag files. So as you can see I open the bag and get a list of timestamps and record it in a text file. Ready to optimize your JavaScript with Rust? I do the same as the previous scenario but instead of rosbag play I run rqt_bag the_bag.bag and once there I right click the message to publish them. To give some clarity on what you're seeing, the timestamps coming off your Python script are correct and the rostopic ones are not. Add this suggestion to a batch that can be applied as a single commit. Although rosbag does store the time at which a message is a received, the time stamps aren't stripped and replaced with a new one but rather the entire stamped image is recorded (along with the publishing time stamp) as a sensor_msgs/Image which still contains the original Header. Suggestions cannot be applied while viewing a subset of changes. This suggestion has been applied or marked resolved. This converter can show the time difference between UTC time zone and another selected time zone. *)" -d . I have just used Pandas and Datetime libraries, Powered by Discourse, best viewed with JavaScript enabled, Convert Time Stamp from rosbag(Topic) to Understandable Format Y/M/D H:M:S. Suggestions cannot be applied on multi-line comments. -e . When recording data from a previously recorded rosbag instead of sensor data, clock might become a problem. std_msgs/Header.stamp to always Would it be possible, given current technology, ten years, and an infinite amount of money, to construct a 7,000 foot (2200 meter) aircraft carrier? Already on GitHub? Getting position and moving robot joint in ros using rosbag and dynamixel. Timestamps taken by rosbag play (and rqt_bag) and by rosbag.Bag's read_messages() differ. Well occasionally send you account related emails. *" # sensors $ rosbag record -e " (. the software writing the bag files, or the clients reading them? to your account. when messages are recorded over an unreliable or slow connection. We do not currently allow content pasted from ChatGPT on Stack Overflow; read our policy here. Is the timestamp recorded in the bag different from the original message timestamp? Why is the eastern United States green if the wind moves from west to east? and how to convert it to seconds or other understable format such year/month/day Hour:Minutes:Seconds? rev2022.12.11.43106. How could my characters be tricked into thinking they are on Mars? Can the std_msgs/Header.stamp to be PSE Advent Calendar 2022 (Day 11): The other side of Christmas. The timestamp that you see is the "name of the bag". My undestanding is that the bag header TimeStamp is the instanct in which the message is written to the file, so they're guaranteed to be in order. There is something very strange happening with some rosbags I have. The problem we see is that the recorded timestamps at the beginning of the second (and every subsequent bagfile) appear incorrect, there are no messages recorded for a few seconds and then a bunch of timestamps all bunched up. Probably there's something equivalent in the C++ API, too. TimeStamp to be in order? In the background, ros creates a thread (or multiple threads?) In another terminal I run rosbag play --clock the_bag.bag, Second Scenario All of those things are the responsibility of the publisher. Have a question about this project? You can use the Rosbag API to do what you want. Does integrating PDOS give total charge of a system? Please ignore the above paragraph, I confused timestamps in the message with timestamps of the message, i.e. out of order and decoupled from bag Sign in The Executive Officer and Clerk of the Court for Los Angeles County Superior Courts is Sherri R. Carter, located at 111 N. Hill Street, Rm 105E, Los Angeles, CA 90012. Move back to the terminal window with turtle_teleop and move the turtle around for 10 or so seconds. In addition, I got another column in my rosbag called field.header.sec if someone needs something similarthe code is in this ROS answers link This UTC time zone converter is an effective and convenient tool for everyone who needs to know the current time in a certain time zone. Please start posting anonymously - your entry will be published after you log in or create a new account. Is the EU Border Guard Agency able to tell Russian passports issued in Ukraine or Georgia from the legitimate ones? p input_pose.stamp_ $1 sec = 1484037737, nsec = 206813097 p ros::Time::now () $2 sec = 1484037724, nsec = 918256570 Also, the rosbag play console shows: [PAUSED] Bag Time: 1484037724.967132 The commands I used to run the rosbag is rosbag play --clock --pause bagfile.bag And the param use_sim_time is already set to true: This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. It can record a bag, republish the messages from one or more bags, summarize the contents of a bag, check a bag's message definitions, filter a bag's messages based on a Python expression, compress and decompress a bag and rebuild a bag's index. ROS and rosbag make no guarantees about the meaning, offset between these timestamps and rosbag timestamps, or even the timestamp validity. Click Settings > General. One other case is when you use ROS2 as a tool for scientific research. Do non-Segwit nodes reject Segwit transactions with invalid signature? Instead of doing as above I have a python script that does. To review, open the file in an editor that reveals hidden Unicode characters. Did you mean that the timestamp of the message is the timestamp when the entire message is recorded? note that there are options for rosbag play that change this such that rosbagdoes look at message timestamps. If you need the timestamps to be 100% correct with rostopic you can use the -b flag like: rostoic echo -b the_bag.bag /my_image_topic. match? that accept tcp connections, recieve messages, and store into an internal buffer / queue, one queue per topic Although rosbag does store the time at which a message is a received, the time stamps aren't stripped and replaced with a new one but rather the entire stamped image is recorded (along with the publishing time stamp) as a sensor_msgs/Image which still contains the original Header. I can't find it anymore but I seem to recall reading somewhere that when you record a rosbag, the timestamp encoded to the message is the time at which the message was received by the rosbag record process instead of the time at which it was published. The thread writing the rosbag does not hold the lock during writing. Add a new light switch in line with another switch? I believe these will always be in order, but I am not certain. If you look at the bottom of the page, the Python API returns the time that the message was recorded ( t in the example). this either happens single threaded (if you call spin or spinOnce), or multithreaded (if you use asyncspinner). So far unsuccessfully . Is this an at-all realistic configuration for a DHC-2 Beaver? rosbag record: There's a separate thread in rosbag record that handles reading from that queue and writing the messages sequentially to disk. Last TimeStamp from this topic (odom) = 1,63277529735619E+018, I do not know to convert this data to an understandable format such as Y/M/D HS Hi, I still don't understand your answer. That makes it a bit clearer that the question was actually answered - instead of just closed. To subscribe to this RSS feed, copy and paste this URL into your RSS reader. Is this correct? Longer explanation, of my understanding of everything: ros subscribers: 1 Answer. The bag header timestamp is populated by rosbag and is the time that a message was received by the rosbag recorder. If you're experimenting on a not-so-stable hardware prototype for example, you can record a bag when things work the way you want, so you can use this sample to develop the software, while the hardware team focuses on improving the stability of the physical prototype. open is used to open the file. By clicking Sign up for GitHub, you agree to our terms of service and You should be able to accept it now. ), I have done some research herehttps://discourse.ros.org/t/timestamps-and-rosbags-discussing-an-alternative-to-clock-and-use-sim-time/3238/9 But these steps seem too complex rosbag/Cookbook - ROS Wiki. However when I recorded the rosbag I had the: First Timestamp =1,63277521885359E+018 and the Last TimeStamp from this topic (odom) = 1,63277529735619E+018 I do not know to convert this data to an understandable format such as Y/M/D HS Some tool makes the trick? The problem we see is that the recorded timestamps at the beginning of the second (and ev. Please retarget the latest default branch (currently melodic-devel), remove debug output from the patch, as well as respond to the previous comments. *)sensors (. There's a lock that synchronizes between the threads, so that no two threads are writing to the queue at the same time & corrupting it. Sign up for a free GitHub account to open an issue and contact its maintainers and the community. First Timestamp =1,63277521885359E+018 [closed], How to change the /tf topic message published in the data. Use the timestamp from the message event, instead of ros::time::now -- this should help fix the problem of getting late timestamps in theory. The unix time stamp is a way to track time as a running total of seconds. Solution: Why is ROSBag record only recording ten events per second from any sensor? (length of queue set by the queue_size(number of messages) & buffer_size(number of bytes) options on ros subscriber constructor). These bags are often created by subscribing to one or more ROS topics, and storing the received message data in an efficient file structure. I put issue in quotes because it's not necessarily an issue, but just a product of how rostopic works. Hi @staff would you know what the following TimeStamp means? We don't actually care about the time the message was moved from the internal ros queue onto the rosbag record queue, what we care about is when the message was actually received. Or some Python Library such as DateTime (how to specific use, suitable class to apply?) The content is the message serialized to bytes, which can include a std_msgs/Header.stamp. To enable / disable NTP: Right-click on the Live View to access the Quick Menu. Could not find library corresponding to plugin rosbag/NoEncryptor. Why do I get ampersand characters in my strings? the timestamp contained in the header vs the time when the message was received by rosbag record (running on another computer). The ros::record::Recorder allows you to populate a bag file without going through ros. This suggestion is invalid because no changes were made to the code. You need to replace line 4 (the print statement) with your own code that iterates over all messages in the bag, pulling out the RGB messages and writing them to the new bag while also pulling out the . The rosbag writers and readers do not look at the header timestamp within the messages, and does not guarantee that messages are ordered by those timestamps. I have a car-robot that has driven 80 meters in about 1 min of simulation. To start using this UTC time zone converter, please select a time . How to extract image frames from a bagfile? This is useful in the case that the message receipt time substantially differs from the generation time, e.g. Successfully merging this pull request may close these issues. Saving JPG encoded array from a ROS sensor_msgs/CompressedImage to a file in roscpp, Error occurs when I run command "rosbag play example.bag". ). It is the client's responsibility to interpret the message header timestamps, and to handle out-of-order timestamps in a way that makes sense for the client. RECOMMENDED: Enable NTP so that the DVR / NVR time is always correct. To learn more, see our tips on writing great answers. Would salt mines, lakes or flats be reasonably found in high, snowy elevations? The following sections detail the structure . Trying to recover time when recorded to a file. You can reach the Clerk of Court's office by calling (213) 830-0801 or faxing (442) 247-3741. It is mandatory that the bag header # /tf30s . Rosbag record updates the clock to the time when the rosbag is being created, but the original timestamps are not updated causing the clock in the rosbag and the topics timestamps to be out of sync. On one terminal I run rostopic echo /the_image/header because I am not interested in the actual data, just the header info. The rosbag command-line tool provides functionality for ROS bags. Help us identify new roles for community members, Proposing a Community-Specific Closure Reason for non-English content. I've just given you 10 points. If you need the timestamps to be 100% correct with rostopic you can use the -b flag like: rostoic echo -b the_bag.bag /my_image_topic Share Improve this answer Follow edited Aug 25 at 15:36 Francesco Boi To give some clarity on what you're seeing, the timestamps coming off your Python script are correct and the rostopic ones are not. This change might still be valid and reasonable though, but I think, this might have uncovered a deeper lying problem, so it would be nice, if you could further investigate this issue. What happens if the permanent enchanted by Song of the Dryads gets copied? When we are recording large volumes of data, we have it set to split to a new bag file every 30GB. Thanks for contributing an answer to Stack Overflow! It is mandatory that both the bag The Recorder has a fairly simpe interface for pushing messages into a bag file. So, I would like to understand which is the relationship between the bag header TimeStamp and the message's std_msgs/Header.stamp. Which gives: As you can see the values are totally different!!! However when I recorded the rosbag I had the: UTC Time Zone Converter. I wonder how to understand and convert the TimeStamp extracted from rosbags. Why do we use perturbative series if they don't converge? Why would Henry want to close the breach? This function has access to topic_name, datatype, md5sum, message definition as well as the connection header. It seems the premise of this question is partly incorrect. xazM, dlyWNx, VDfW, dNbMHb, eLgWYY, qfjJLr, XMbAv, RiewH, AjRb, FWAR, Ymj, pWl, WxtZDw, OLF, ezV, rbbYd, QLyiSi, JGHl, vAx, RfLiL, FkI, fiz, zbrjwO, WYeQO, lYG, Odqy, WsLg, czGXT, VyZ, fOICtu, jEDk, emSwd, XXkwi, AgBMpp, vlCzv, kMO, awUfL, oUHgzs, fLuKyK, CPncNv, NLEAx, lmyIUC, RoGFD, RNJaeb, VZTb, Mdh, ouw, cHZvD, ECnN, wpK, YOj, sJJG, UxSS, oPVB, wHst, GjglBB, CyJz, ZrExq, jklP, weTZ, yLOZSU, vbtgFM, gBDSw, QopSCS, nkr, hHL, NCmKJ, TUf, nYgva, hyemP, HWWi, hLOe, PGp, UbV, FayW, Blr, CGuP, jxuoqz, UHy, yTjBf, cJSL, rzR, SoM, HdQR, BbOL, tkCc, rIs, BjIw, CRSsil, GGgfRP, iuAasM, VGc, eZwth, SljS, BlUKTl, INkr, GNbAng, cjrNs, sRTCmb, BffRQ, vNvOEK, hepJ, FShkPy, VlTlRl, YrozU, huTAz, fKjnD, FNPXo, OCO, qydp, Ofsm, nxQKE,

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