NTIRE 2021 Video Super-Resolution Challenge - Track2. Spatio-Temporal

Organized by Radu - Current server time: Jan. 25, 2021, 10:51 a.m. UTC


Jan. 5, 2021, midnight UTC


March 1, 2021, midnight UTC


Competition Ends
March 8, 2021, 11:59 p.m. UTC

NTIRE Workshop and Challenges @ CVPR 2021

Video Super-Resolution Track 2. Spatio-Temporal

Important Dates

  • 2020.01.01 train and validation data release, test input release
  • 2020.01.05 validation server online
  • 2020.03.01 testing server online
  • 2020.03.08 test result submission deadline
  • 2020.03.09 fact sheet / code / model submission deadline
  • 2020.03.11 test preliminary score release to the participants
  • 2020.03.28 challenge paper submission deadline
  • 2020.04.13 camera-ready deadline
  • 2020.06.15 workshop day

Challenge Overview

The 6th edition of NTIRE: New Trends in Image Restoration and Enhancement workshop will be held June 15th, 2021 in conjunction with CVPR 2021 virtually.

Image manipulation is a key computer vision tasks, aiming at the restoration of degraded image content, the filling in of missing information, or the needed transformation and/or manipulation to achieve a desired target (with respect to perceptual quality, contents, or performance of apps working on such images). Recent years have witnessed an increased interest from the vision and graphics communities in these fundamental topics of research. Not only has there been a constantly growing flow of related papers, but also substantial progress has been achieved.

Each step forward eases the use of images by people or computers for the fulfillment of further tasks, as image manipulation serves as an important frontend. Not surprisingly then, there is an ever growing range of applications in fields such as surveillance, the automotive industry, electronics, remote sensing, or medical image analysis etc. The emergence and ubiquitous use of mobile and wearable devices offer another fertile ground for additional applications and faster methods.

This workshop aims to provide an overview of the new trends and advances in those areas. Moreover, it will offer an opportunity for academic and industrial attendees to interact and explore collaborations.

Jointly with NTIRE workshop we have an NTIRE challenge on examble-based Video Super-Resolution, that is, the task of super-resolving an input video with a upsampling factor x4 based on a set of prior examples of high-resolution videos. The aim of the challenge is to obtain a solution capable to produce high-resolution results with the best fidelity (PSNR, SSIM) to the ground truth.

The top ranked participants will be awarded and invited to follow the CVPR submission guide for workshops to describe their solution and to submit to the associated NTIRE workshop at CVPR 2021.

More details are found on the data section of the competition.


To learn more about each competition, to participate in the challenge, and to access the dataset, everybody is invited to register. The training data is available to the registered participants.

Provided Resources

  • Scripts: With the dataset the organizers will provide scripts to facilitate the reproducibility of the images and performance evaluation results after the validation server is online. More information is provided on the data page.
  • Contact: You can use the forum on the data description page (highly recommended!) or directly contact the challenge organizers by email ( Seungjun Nah (seungjun.nah [at] gmail.com), Sanghyun Son (thstkdgus35 [at] snu.ac.kr), Suyoung Lee (esw0116 [at] snu.ac.kr) and Radu Timofte (Radu.Timofte [at] vision.ee.ethz.ch)) if you have doubts or any question.

NTIRE Workshop and Challenges @ CVPR 2021

Video Super-Resolution Track 2. Spatio-Temporal


We evaluate the submitted results by comparing them with the ground truth video frames.

The final goal of this challenge is to generate high-resolution video from a low-resolution input video. During the development and testing phase, challenge participants will submit the super-resolved frames.

To measure the fidelity, we use the standard Peak Signal to Noise Ratio (PSNR) and, complementarily, the Structural Similarity (SSIM) index as they are often employed in the literature. PSNR and SSIM implementations are found in most of the image processing toolboxes. We report the average results over all the processed frames belonging to the evaluation dataset.

import imageio
from skimage.metrics import peak_signal_noise_ratio, structural_similarity

ref_img = imageio.imread('ref_img_name.png')
res_img = imageio.imread('res_img_name.png')

psnr = peak_signal_noise_ratio(ref_img, res_img)
ssim = structural_similarity(ref_img, res_img, multichannel=True, gaussian_weights=True, use_sample_covariance=False)


During the development and testing phase, the participants can submit part of the results to get feedback from the CodaLab server. In parallel, during the development phase, the participants will make their own evaluation with the validation set. We recommend NOT using the validation set for training purposes. At the testing phase, the participants will submit the whole restoration results of the test set via email. This should match the last submission to the CodaLab (corresponding frames).

  1. The processed output images should be named by the corresponding sequence number and frame number that is consistent with the provided inputs. For example, 0th frame from sequence 000 is "000_00000000.png", and the 60th frame from sequence 013 is "013_00000060.png".

  2. The results should contain every 10th frame, starting from "000_00000009.png" to "000_00000089.png". There should be 270 frames in total. No other frames should be submitted.

  3. Create a ZIP archive containing all the output images. The ZIP archive should also contain a readme.txt file. Note that the archive should not include folders and all the frames/files should be in the root of the archive.

  4. The readme.txt file should contain the following lines filled in with the runtime per image (in seconds) of the solution, 1 or 0 accordingly if employs CPU or GPU at runtime, and 1 or 0 if employs extra data for training the models or not.

    runtime per image [s] : 10.43 
    CPU[1] / GPU[0] : 1
    Extra Data [1] / No Extra Data [0] : 1
    Other description : Solution based on A+ of Timofte et al. ACCV 2014. We have a Matlab/C++ implementation, and report single core CPU runtime. The method was trained on Train 91 of Yang et al. and BSDS 200 of the Berkeley segmentation dataset. 

    The last part of the file can have any description you want about the code producing the provided results (dependencies, link, scripts, etc.) The provided information is very important both during the validation period when different teams can compare their results/solutions but also for establishing the final ranking of the teams and their methods.

  5. A valid example dummy submission file can be found here.

After the testing phase, the participants will submit the fact sheet and source code to all the challenge organizers: Submission account (ntire.snu [at] gmail.com), Seungjun Nah (seungjun.nah [at] gmail.com), Sanghyun Son (thstkdgus35 [at] snu.ac.kr), Suyoung Lee (esw0116 [at] snu.ac.kr) and Radu Timofte (Radu.Timofte [at] vision.ee.ethz.ch) by email. The final submission should be made by the following rules:

  1. All the restored frames should be submitted. This is different from the CodaLab submission.
  2. The submitted result must be from the same method that generated the last submission to the CodaLab. We will check the consistency. Otherwise, the submission is void.
  3. Either the testing source code or executable must be submitted, too. Reproducibility is a necessary condition.
  4. Factsheet describing the method details should be submitted together. The factsheet format is provided with data. Participants must submit a compiled pdf file and the tex source. We encourage participants to provide details and enclose figure image sources together. This helps writing the challenge summary report.

Fact sheet template

Each participating team in the final testing phase should use the following NTIRE 2021 Video Super-Resolution challenge factsheet template to describe their solution(s):

template download: https://competitions.codalab.org/my/datasets/download/82fa7168-8886-4083-add8-d37ec9d0618c

Email submission format

Please use the following format to submit your final results, fact sheet, code, model (with trained parameters). We will run the testing code to reproduce the results. Training code doesn't necessarily have to be included. The code and the model is to be posted on the NTIRE 2021 website.

to: ntire.snu@gmail.com; seungjun.nah@gmail.com; thstkdgus35@snu.ac.kr; esw0116@snu.ac.kr; radu.timofte@vision.ee.ethz.ch  
cc: your_team_members  
title: [NTIRE 2021 Video Super-Resolution Challenge - Track 2] - [TEAM_NAME]
body should include:  
a) the challenge name  
b) team name  
c) team leader's name and email address  
d) rest of the team members  
e) team members with NTIRE 2021 sponsors  
f) team name and user names on NTIRE 2021 CodaLab competitions (if any)  
g) executable/source code attached or download links.  
h) fact sheet attached  
i) download link to the results of all of the test frames (99 x 30 = 2970 frames)  

Multi-submission policy

Following the previous NTIRE and AIM challenges, we accept multiple submissions from a single team if they are significantly different.
However, solutions with minor differences can be rejected by the organizers. For example, if solution A and B are submitted where B is an ensemble method of A, we do not consider them to be essentially different.

If you are preparing multiple submissions, please contact the organizers in advance for clarification.

NTIRE Workshop and Challenges @ CVPR 2021

Video Super-Resolution Track 2. Spatio-Temporal

These are the official rules (terms and conditions) that govern how the NTIRE 2021 challenge on example-based video super-resolution will operate. This challenge will be simply reffered to as the "challenge" or the "contest" throghout the remaining part of these rules and may be named as "NTIRE" or "REDS" benchmark, challenge, or contest, elsewhere (our webpage, our documentation, other publications).

In these rules, "we", "our", and "us" refer to the organizers (Seungjun Nah (seungjun.nah [at] gmail.com), Sanghyun Son (thstkdgus35 [at] snu.ac.kr), Suyoung Lee (esw0116 [at] snu.ac.kr) and Radu Timofte (Radu.Timofte [at] vision.ee.ethz.ch)) of NTIRE challenge and "you" and "yourself" refer to an eligible contest participant.

Note that these official rules can change during the contest until the start of the final phase. If at any point during the contest the registered participant considers that can not anymore meet the eligibility criteria or does not agree with the changes in the official terms and conditions then it is the responsability of the participant to send an email to the organizers such that to be removed from all the records. Once the contest is over no change is possible in the status of the registered participants and their entries.

1. Contest description

This is a skill-based contest and chance plays no part in the determination of the winner(s).

The goal of the contest is to super-resolve an input video to an output video in the spatial domain with an upsampling factor x4 and in the temporal domain with an upsampling ratio x2. The challenge is called video spatio-temporal super-resolution.

Focus of the contest: It will be made available REDS dataset adapted for the specific needs of the challenge. The images have a large diversity of contents. We will refer to this dataset, its partition, and related materials as REDS. The dataset is divided into training, validation and testing data. The aim is to achieve super-resolved output videos with the highest fidelity (PSNR) to the ground truth. The participants will not have access to the ground truth images from the test data. The ranking of the participants is according to the performance of their methods on the test data. The participants will provide descriptions of their methods, details on (run)time complexity, platform and (extra) data used for modeling. The winners will be determined according to their entries, the reproducibility of the results and uploaded codes or executables, and the above mentioned criteria as judged by the organizers.

2. Eligibility

You are eligible to register and compete in this contest only if you meet all the following requirements:

  • You are an individual or a team of people willing to contribute to the open tasks, who accepts to follow the rules of this contest
  • You are not an NTIRE challenge organizer or an employee of NTIRE challenge organizers
  • You are not involved in any part of the administration and execution of this contest
  • You are not a first-degree relative, partner, household member of an employee or of an organizer of NTIRE challenge or of a person involved in any part of the administration and execution of this contest

This contest is void wherever it is prohibited by law.

Entries submitted but not qualified to enter the contest, it is considered voluntary and for any entry you submit, NTIRE reserves the right to evaluate it for scientific purposes, however, under no circumstances will such entries qualify for sponsored prizes. If you are an employee, affiliated with or representant of any of the NTIRE challenge sponsors then you are allowed to enter in the contest and get ranked, however, if you will rank among the winners with eligible entries you will receive only a diploma award and none of the sponsored money, products or travel grants.

NOTE: Industry and research labs are allowed to submit entries and to compete in both the validation phase and final test phase. However, in order to get officially ranked on the final test leaderboard and to be eligible for awards the reproducibility of the results is a must and, therefore, the participants need to make available and submit their codes or executables. All the top entries will be checked for reproducibility and marked accordingly.

We will have 3 categories of entries in the final test ranking:

  1. checked with publicly released codes
  2. checked with publicly released executable
  3. unchecked (with or without released codes or executables)

3. Entry

In order to be eligible for judging, an entry must meet all the following requirements:

Entry contents: The participants are required to submit image results and code or executables. To be eligible for prizes, the top ranking participants should publicly release their code or executables under a license of their choice, taken among popular OSI-approved licenses (http://opensource.org/licenses) and make their code or executables online accessible for a period of not less than one year following the end of the challenge (applies only for top three ranked participants of the competition). To enter the final ranking the participants will need to fill out a survey (fact sheet) briefly describing their method. All the participants are also invited (not mandatory) to submit a paper for peer-reviewing and publication at the NTIRE Workshop and Challenges (to be held on November 2, 2019, Seoul, Korea). To be eligible for prizes, the participants' score must improve the baseline performance provided by the challenge organizers.

Use of the provided data: All data provided by NTIRE are freely available to the participants from the website of the challenge under license terms provided with the data. The data are available only for open research and educational purposes, within the scope of the challenge. NTIRE and the organizers make no warranties regarding the database, including but not limited to warranties of non-infringement or fitness for a particular purpose. The copyright of the images remains in the property of their respective owners. By downloading and making use of the data, you accept full responsibility for using the data. You shall defend and indemnify NTIRE and the organizers, including their employees, Trustees, officers and agents, against any and all claims arising from your use of the data. You agree not to redistribute the data without this notice.

  • Test data: The organizers will use the test data for the final evaluation and ranking of the entries. The ground truth test data will no be made available to the participants during the contest.

  • Training and validation data: The organizers will make available to the participants a training and a validation dataset with ground truth images.

  • Post-challenge analyses: The organizers may also perform additional post-challenge analyses using extra-data, but without effect on the challenge ranking.

  • Submission: The entries will be online submitted via the CodaLab web platform. During the development phase, while the validation server is online, the participants will receive immediate feedback on validation data. The final evaluation will be computed automatically on the test data submissions, but the final scores will be released after the challenge is over.

  • Original work, permissions: In addition, by submitting your entry into this contest you confirm that, to the best of your knowledge: - your entry is your own original work; and - your entry only includes material that you own, or that you have permission to use.

4. Potential use of entry

Other than what is set forth below, we are not claiming any ownership rights to your entry. However, by submitting your entry, you:

Are granting us an irrevocable, worldwide right and license, in exchange for your opportunity to participate in the contest and potential prize awards, for the duration of the protection of the copyrights to:

  • Use, review, assess, test and otherwise analyze results submitted or produced by your code or executable and other material submitted by you in connection with this contest and any future research or contests by the organizers; and
  • Feature your entry and all its content in connection with the promotion of this contest in all media (now known or later developed);
  • Agree to sign any necessary documentation that may be required for us and our designees to make use of the rights you granted above;
  • Understand and acknowledge that us and other entrants may have developed or commissioned materials similar or identical to your submission and you waive any claims you may have resulting from any similarities to your entry;
  • Understand that we cannot control the incoming information you will disclose to our representatives or our co-sponsor’s representatives in the course of entering, or what our representatives will remember about your entry. You also understand that we will not restrict work assignments of representatives or our co-sponsor’s representatives who have had access to your entry. By entering this contest, you agree that use of information in our representatives’ or our co-sponsor’s representatives unaided memories in the development or deployment of our products or services does not create liability for us under this agreement or copyright or trade secret law;
  • Understand that you will not receive any compensation or credit for use of your entry, other than what is described in these official rules.

If you do not want to grant us these rights to your entry, please do not enter this contest.

5. Submission of entries

The participants will follow the instructions on the CodaLab website to submit entries

The participants will be registered as mutually exclusive teams. Each CodaLab account is allowed to submit only one single final entry. Multiple submissions from a single team is valid only when they are significantly different. It is recommended to check the validity with the organizers in advance. We are not responsible for entries that we do not receive for any reason, or for entries that we receive but do not work properly.

The participants must follow the instructions and the rules. We will automatically disqualify incomplete or invalid entries.

6. Judging the entries

The board of NTIRE will select a panel of judges to judge the entries; all judges will be forbidden to enter the contest and will be experts in causality, statistics, machine learning, computer vision, or a related field, or experts in challenge organization. A list of the judges will be made available upon request. The judges will review all eligible entries received and select three winners for each of the two competition tracks based upon the prediction score on test data. The judges will verify that the winners complied with the rules, including that they documented their method by filling out a fact sheet.

The decisions of these judges are final and binding. The distribution of prizes according to the decisions made by the judges will be made within three (3) months after completion of the last round of the contest. If we do not receive a sufficient number of entries meeting the entry requirements, we may, at our discretion based on the above criteria, not award any or all of the contest prizes below. In the event of a tie between any eligible entries, the tie will be broken by giving preference to the earliest submission, using the time stamp of the submission platform.

7. Prizes and Awards

The financial sponsors of this contest are listed on NTIRE 2021 workshop web page. There will be economic incentive prizes and travel grants for the winners (based on availability) to boost contest participation; these prizes will not require participants to enter into an IP agreement with any of the sponsors, to disclose algorithms, or to deliver source code to them. The participants affiliated with the industry sponsors agree to not receive any sponsored money, product or travel grant in the case they will be among the winners.

Incentive Prizes for each track competitions (tentative, the prizes depend on attracted funds from the sponsors)

1st place: ?00$ + award certificate
2nd place: ?00$ + award certificate
3rd place: ?00$ + award certificate

8. Other sponsored events

Publishing papers is optional and will not be a condition to entering the challenge or winning prizes. The top ranking participants are invited to submit a maximum 8-pages paper (CVPR 2021 author rules) for peer-reviewing to NTIRE workshop.

The results of the challenge will be published together with NTIRE 2021 workshop papers in the 2021 CVPR Workshops proceedings.

The top ranked participants and participants contributing interesting and novel methods to the challenge will be invited to be co-authors of the challenge report paper which will be published in the 2021 CVPR Workshops proceedings. A detailed description of the ranked solution as well as the reproducibility of the results are a must to be an eligible co-author.

9. Notifications

If there is any change to data, schedule, instructions of participation, or these rules, the registered participants will be notified at the email they provided with the registration.

Within seven days following the determination of winners, we will send a notification to the potential winners. If the notification that we send is returned as undeliverable, or you are otherwise unreachable for any reason, we may award the prize to an alternate winner, unless forbidden by applicable law.

The prize such as money, product, or travel grant will be delivered to the registered team leader given that the team is not affiliated with any of the sponsors. It's up to the team to share the prize. If this person becomes unavailable for any reason, the prize will be delivered to be the authorized account holder of the e-mail address used to make the winning entry.

If you are a potential winner, we may require you to sign a declaration of eligibility, use, indemnity and liability/publicity release and applicable tax forms. If you are a potential winner and are a minor in your place of residence, and we require that your parent or legal guardian will be designated as the winner, and we may require that they sign a declaration of eligibility, use, indemnity and liability/publicity release on your behalf. If you, (or your parent/legal guardian if applicable), do not sign and return these required forms within the time period listed on the winner notification message, we may disqualify you (or the designated parent/legal guardian) and select an alternate selected winner.

The terms and conditions are inspired by and use verbatim text from the `Terms and conditions' of ChaLearn Looking at People Challenges and of the NTIRE 2017, 2018, 2019, and 2020 challenges and the AIM 2019, 2020 challenges.

NTIRE Workshop and Challenges @ CVPR 2021

Video Super-Resolution Track 2. Spatio-Temporal


The NTIRE challenge on Video Super-Resolution is organized jointly with the NTIRE 2021 workshop. The results of the challenge will be published at NTIRE 2021 workshop and in the CVPR 2021 Workshops proceedings.

Seungjun Nah (seungjun.nah [at] gmail.com), Sanghyun Son (thstkdgus35 [at] snu.ac.kr), Suyoung Lee (esw0116 [at] snu.ac.kr) and Radu Timofte (Radu.Timofte [at] vision.ee.ethz.ch) are the contact persons and direct managers of the NTIRE challenge.

More information about NTIRE workshop and challenge organizers is available here: https://data.vision.ee.ethz.ch/cvl/ntire21/


Start: Jan. 5, 2021, midnight

Description: Development phase - submit the results on the validation data.


Start: March 1, 2021, midnight

Description: Testing phase - submit the results on the test data.

Competition Ends

March 8, 2021, 11:59 p.m.

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# Username Score
1 zhangqi 30.89
2 viasu 30.89
3 whu_hj 26.30