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by C. Helmrich

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Christian R. Helmrich, born in 1981 in Cuxhaven, Germany, received a B. Sc. degree in computer science from
Capitol Technology University (formerly Capitol College), Laurel, MD, USA, in 2005 and a M. Sc. degree in information & media technology from
TU Hamburg-Harburg (TUHH), Germany, in 2008. Between 2008 and 2013 he worked on numerous speech and audio coding solutions at the
Fraunhofer Institute for Integrated Circuits (IIS), Erlangen, Germany, partly as a Senior Engineer. From 2013 until 2016 Mr. Helmrich continued his work as a research assistant at the Audio Labs Erlangen, a joint institution of Fraunhofer IIS and the University of Erlangen-Nürnberg, Germany, where he completed his Dr.-Ing. degree with a dissertation on audio signal analysis and coding. In 2016 Dr. Helmrich joined the Video Coding & Analytics department of the
Fraunhofer Heinrich Hertz Institute (HHI), Berlin, Germany, as a next-generation video coding researcher and developer. His main interests include audio and video acquisition, coding, storage, and preservation as well as restoration from analog sources.

Dr. Helmrich participated in and contributed to several standardization activities in the fields of audio and video coding. He is author or co-author of more than 60 publications and a Senior Member of the IEEE. He is also on LinkedIn.

Christian Helmrich's publications in chronologically descending order, 2025–2007

2025

C. R. Helmrich, S. Pientka, et al., «Proposal for replacement of DST-II by DST-IV in biomedical waveform coding», «Description and correction of errors in H.BWC test model since January meeting», «Speedup of H.BWC reference software via pre-search and predictor optimization», «Core experiment CE 1-2 on improved deblocking in biomedical waveform coding», ITU documents VCEG-BX10 – VCEG-BX13, Teleconf., Apr. 2025. Document files (names starting with VCEG-BX1...).

J. Pfaff, T. Nguyen, S. Pientka, C. R. Helmrich, G. Hege, H. Kirchhoffer, P. Haase, H. Schwarz, D. Marpe, and T. Wiegand, «Harmonization of entropy coding methods in H.BWC», ITU document VCEG-BX14, Teleconf., Apr. 2025. Document file.

G. Marković, E. Fotopoulou, J. F. Kiene, and C. R. Helmrich, «Efficient MDCT-Based Multi-Channel Coding with Perceptual Whitening and Broadband ILD Compensation», in Proc. IEEE Int. Conf. Acoustics, Speech, and Signal Processing (ICASSP), Hyderabad, Apr. 2025. Paper.

2024

J. Pfaff, H. Kirchhoffer, C. Rudat, S. Pientka, C. R. Helmrich, H. Schwarz, D. Marpe, and T. Wiegand, «Description of Fraunhofer HHI's response to the Call for Evidence on the compression of biomedical waveform data», ITU document VCEG-BU03, Teleconf., Jan. 2024. Document file, conf. slides.

A. Henkel, C. R. Helmrich, T. Hinz, J. Brandenburg, A. Wieckowski, B. Bross, D. Marpe, and T. Wiegand, «Fast First Pass in Two-Pass Video Encoding Using Sub-Sampling», in Proc. IEEE Picture Coding Symposium (PCS), Taichung, June 2024. Paper.

C. R. Helmrich, V. George, V. V Menon, A. Wieckowski, B. Bross, and D. Marpe, «Fast Constant-Quality Video Encoding Using VVenC with Rate Capping Based on Pre-Analysis Statistics», in Proc. IEEE Int. Conf. Image Processing (ICIP), Abu Dhabi, Oct. 2024. Early manuscript, paper.

V. V Menon, C. R. Helmrich, A. Wieckowski, B. Bross, and D. Marpe, «Convex-Hull Estimation Using XPSNR for Versatile Video Coding», in Proc. IEEE Int. Conf. Image Processing (ICIP), Abu Dhabi, Oct. 2024. Paper.

J. Pfaff, H. Kirchhoffer, C. Helmrich, S. Pientka, C. Rudat, H. Schwarz, D. Marpe, and T. Wiegand, «Description of Fraunhofer HHI's response to the Call for Proposals on the compression of biomedical waveform data», ITU document VCEG-BW02, Kemer, Nov. 2024. Document file.

C. R. Helmrich, H. Kirchhoffer, J. Pfaff, S. Pientka, C. Rudat, H. Schwarz, D. Marpe, and T. Wiegand, «Optimization of HHI's CfP response for rate constrained or perceptual use cases», ITU document VCEG-BW12, Kemer, Nov. 2024. Document file.

2023

A. Wieckowski, J. Brandenburg, C. Bartnik, V. George, J. Güther, G. Hege, C. R. Helmrich, A. Henkel, T. Hinz, C. Lehmann, C. Stoffers, B. Bross, H. Schwarz, D. Marpe, and T. Schierl, «Update on open, optimized VVC implementations VVenC and VVdeC», document JVET-AC0266, Teleconf., Jan. 2023. Zip file ( July update).

C. R. Helmrich, A. Henkel, T. Hinz, A. Wieckowski, B. Bross, and D. Marpe, «Finalization of VVenC's Screen Content Detector and Two-Pass Rate Control Using Pre-Filtering Statistics», in Proc. IEEE International Conf. Image Processing (ICIP), Kuala Lumpur, Oct. 2023. Early manuscript, paper.

V. V Menon, A. Henkel, P. T Rajendran, C. R. Helmrich, A. Wieckowski, B. Bross, C. Timmerer, and D. Marpe, «All-Intra Rate Control Using Low Complexity Video Features for Versatile Video Coding», in Proc. IEEE Int. Conf. Image Processing (ICIP), Kuala Lumpur, Oct. 2023. Paper.

C. R. Helmrich, J. Pfaff, H. Schwarz, D. Marpe, and T. Wiegand, «Information on performance evaluation of audio codecs for 2-channel ECG data», ITU document VCEG-BT05, Hannover, Oct. 2023. Document file.

C. R. Helmrich, C. Rudat, J. Pfaff, H. Schwarz, D. Marpe, and T. Wiegand, «Performance evaluation of audio codecs for multichannel biomedical data», ITU document VCEG-BU01, Teleconf., Dec. 2023. Document file.

C. R. Helmrich, C. Bartnik, J. Brandenburg, A. Wieckowski, B. Bross, and D. Marpe, «A Constrained Variable Bit Rate (CVBR) Algorithm for VVenC, an Open VVC Encoder Implementation», in Proc. IEEE Int. Conf. Visual Communications and Image Processing (VCIP), Jeju, Dec. 2023. Early manuscript, paper, conf. poster, web page.

2022

A. Wieckowski, J. Brandenburg, C. Bartnik, V. George, J. Güther, G. Hege, C. R. Helmrich, A. Henkel, T. Hinz, C. Lehmann, C. Stoffers, B. Bross, H. Schwarz, D. Marpe, and T. Schierl, «Update on open, optimized VVC implementations VVenC and VVdeC», document JVET-Y0136, Teleconf., Jan. 2022. Zip file ( July update).

A. Wieckowski, T. Hinz, C. R. Helmrich, B. Bross, and D. Marpe, «An Optimized Temporal Filter Implementation for Practical Applications», in Proc. IEEE Picture Coding Symposium (PCS), San Jose, Dec. 2022. Paper.

C. R. Helmrich, C. Bartnik, J. Brandenburg, V. George, T. Hinz, C. Lehmann, I. Zupancic, A. Wieckowski, B. Bross, and D. Marpe, «A Scene Change and Noise Aware Rate Control Method for VVenC, an Open VVC Encoder Implementation», in Proc. IEEE Picture Coding Symposium (PCS), San Jose, Dec. 2022. Early manuscript, paper, conf. slides.

2021

A. Wieckowski, J. Brandenburg, C. Bartnik, V. George, J. Güther, G. Hege, C. R. Helmrich, A. Henkel, T. Hinz, C. Lehmann, C. Stoffers, I. Zupancic, B. Bross, H. Schwarz, and D. Marpe, «Update on open, optimized VVC implementations VVenC and VVdeC», document JVET-U0135, Teleconf., Jan. 2021. Zip file ( July update).

C. R. Helmrich, B. Bross, J. Pfaff, H. Schwarz, D. Marpe, and T. Wiegand, «Information on and analysis of the VVC encoders in the SDR HD RA verification test», document JVET-W0150, Teleconf., July 2021. Zip file.

B. Bross, A. Wieckowski, and C. R. Helmrich, «Versatile Video Coding – Open Optimized Implementations», workshop 4, in Proc. IEEE Picture Coding Symposium (PCS), online, July 2021. Video recording on YouTube.

A. Wieckowski, J. Brandenburg, T. Hinz, C. Bartnik, V. George, G. Hege, C. R. Helmrich, A. Henkel, C. Lehmann, C. Stoffers, I. Zupancic, B. Bross, and D. Marpe, «VVenC: An Open and Optimized VVC Encoder Implementation», best open source project award, in Proc. IEEE Int. Conf. Multimedia & Expo (ICME), online, July 2021. Paper.

H. Schwarz, M. Coban, M. Karczewicz, T.-D. Chuang, F. Bossen, A. Alshin, J. Lainema, C. R. Helmrich, and T. Wiegand, «Quantization and Entropy Coding in the Versatile Video Coding (VVC) Standard», IEEE Trans. on Circuits and Systems for Video Technology, vol. 31, no. 10, pp. 3891–3906, Oct. 2021. Article manuscript (Feb. '21), article.

C. R. Helmrich, I. Zupancic, J. Brandenburg, V. George, A. Wieckowski, and B. Bross, «Visually Optimized Two-Pass Rate Control for Video Coding Using the Low-Complexity XPSNR Model», in Proc. IEEE Int. Conf. Visual Communications and Image Processing (VCIP), Munich, Dec. 2021. Early manuscript, paper, conf. poster, web page.

2020

W. Lim, C. R. Helmrich, J. Erfurt, H. Schwarz, D. Marpe, and T. Wiegand, «Pre-Sample Adaptive Offset Filter», document JVET-Q0434, Brussels, Jan. 2020. Zip file.

C. R. Helmrich, M. Siekmann, S. Becker, S. Bosse, D. Marpe, and T. Wiegand, «XPSNR: A Low-Complexity Extension of the Perceptually Weighted Peak Signal-to-Noise Ratio for High-Resolution Video Quality Assessment», in Proc. IEEE Int. Conf. Acoustics, Speech, and Signal Processing (ICASSP), virt/online, May 2020. Paper manuscript, paper, web page.

C. R. Helmrich, S. Bosse, H. Schwarz, D. Marpe, and T. Wiegand, «A Study of the Extended Perceptually Weighted Peak Signal-to-Noise Ratio (XPSNR) for Video Compression with Different Resolutions and Bit Depths», ITU Journal: ICT Discoveries – Special Issue: The Future of Video and Immersive Media, vol. 3, no. 1, online, May 2020. Article manuscript, article, web page.

J. Pfaff, H. Schwarz, D. Marpe, B. Bross, S. De-Luxán-Hernández, P. Helle, C. R. Helmrich, T. Hinz, W.-Q. Lim, J. Ma, T. Nguyen, J. Rasch, M. Schäfer, M. Siekmann, G. Venugopal, A. Wieckowski, M. Winken, and T. Wiegand, «Video Compression Using Generalized Binary Partitioning, Trellis Coded Quantization, Perceptually Optimized Encoding, and Advanced Prediction and Transform Coding», IEEE Trans. on Circuits and Systems for Video Technology, vol. 30, no. 5, pp. 1281–1295, May 2020. Article manuscript (with different title), article.

C. R. Helmrich, «Crosscheck of JVET-S0180 (Addition of a GOP hierarchy of 32 for random access configuration for VTM)», document JVET-S0262, Teleconf., June 2020. Zip file.

A. Wieckowski, J. Brandenburg, C. Bartnik, V. George, J. Güther, G. Hege, C. Helmrich, A. Henkel, T. Hinz, C. Lehmann, C. Stoffers, I. Zupancic, B. Bross, H. Schwarz, and D. Marpe, «Open optimized VVC encoder (VVenC) and decoder (VVdeC) implementations», document JVET-T0099, Teleconf., Oct. 2020. Zip file.

C. R. Helmrich, B. Bross, J. Pfaff, H. Schwarz, D. Marpe, and T. Wiegand, «Information on and analysis of the VVC encoders in the SDR UHD verification test», document JVET-T0103, Teleconf., Oct. 2020. Zip file.

2019

C. R. Helmrich, H. Schwarz, D. Marpe, and T. Wiegand, «Clean-up and Finalization of Perceptually Optimized QP Adaptation Method in VTM», document JVET-M0091, Marrakech, Jan. 2019. Zip file.

C. R. Helmrich and B. Bross, «CE11: Very Strong Deblocking with Conditional Activation Signaling (Test 11.1.1)», document JVET-M0092, Marrakech, Jan. 2019. Zip file.

C. R. Helmrich, H. Schwarz, D. Marpe, and T. Wiegand, «Non-CE3: Improved Robustness for Calculation of Cross-Component Linear Model Parameters», document JVET-M0093, Marrakech, Jan. 2019. Zip file.

C. R. Helmrich, S. Bosse, M. Siekmann, H. Schwarz, D. Marpe, and T. Wiegand, «Perceptually Optimized Bit-Allocation and Associated Distortion Measure for Block-Based Image or Video Coding», in Proc. IEEE Data Compression Conf. (DCC), Snowbird, pp. 172–181, Mar. 2019. Paper manuscript, paper, web page.

C. R. Helmrich, C. Rudat, T. Nguyen, H. Schwarz, D. Marpe, and T. Wiegand, «CE7-related: Joint Chroma Residual Coding with Multiple Modes», document JVET-N0282, Geneva, Mar. 2019. Zip file.

C. R. Helmrich, H. Schwarz, T. Nguyen, C. Rudat, D. Marpe, and T. Wiegand, «CE7: Joint Chroma Residual Coding with Multiple Modes (Tests CE7-2.1, CE7-2.2)», document JVET-O0105, Gothenburg, July 2019. Zip file.

C. R. Helmrich, H. Schwarz, T. Nguyen, C. Rudat, D. Marpe, and T. Wiegand, «CE7-related: Alternative Configuration for Joint Chroma Residual Coding», document JVET-O0543, Gothenburg, July 2019. Zip file.

J. Erfurt, C. R. Helmrich, S. Bosse, H. Schwarz, D. Marpe, and T. Wiegand, «A Study of the Perceptually Weighted Peak Signal-to-Noise Ratio (WPSNR) for Image Compression», in Proc. IEEE International Conf. Image Processing (ICIP), Taipei, pp. 2339–2343, Sep. 2019. Paper manuscript, paper, web page.

S. Bosse, M. Dietzel, S. Becker, C. R. Helmrich, M. Siekmann, H. Schwarz, D. Marpe, and T. Wiegand, «Neural Network Guided Perceptually Optimized Bit-Allocation for Block-Based Image and Video Compression», in Proc. IEEE Int. Conf. Image Processing (ICIP), Taipei, pp. 126–130, Sep. 2019. Paper.

C. Rudat, C. R. Helmrich, J. Lainema, T. Nguyen, H. Schwarz, D. Marpe, and T. Wiegand, «Inter-Component Transform for Color Video Coding», in Proc. IEEE Picture Coding Symposium (PCS), Ningbo, Nov. 2019. Paper manuscript, paper.

2018

C. R. Helmrich, H. Schwarz, D. Marpe, and T. Wiegand, «Improved Perceptually Optimized QP Adaptation and Associated Distortion Measure», document JVET-K0206, Ljubljana, July 2018. Zip file.

C. R. Helmrich, S. Bosse, P. Keydel, H. Schwarz, D. Marpe, and T. Wiegand, «A Spectrally Adaptive Noise Filling Tool for Perceptual Transform Coding of Still Images», in Proc. IEEE Int. Conf. Consumer Electron. (ICCE), Berlin, Sep. 2018. Paper manuscript, paper, web page.

C. R. Helmrich, B. Bross, and J. Erfurt, «AHG10: Corrected Operation of ALF Encoding with Perceptually Optimized QP Adaptation», document JVET-L0181, Macau, Oct. 2018. Zip file.

C. R. Helmrich, «CE7: Adaptive Quantization via Perceptually Optimized QP Adaptation (Test 7.2.6)», document JVET-L0210, Macau, Oct. 2018. Zip file.

C. R. Helmrich and B. Bross, «Very Strong Deblocking Filtering with Conditional Activation Signaling», document JVET-L0523, Macau, Oct. 2018. Zip file.

2017

C. R. Helmrich, Efficient Perceptual Audio Coding Using Cosine and Sine Modulated Lapped Transforms, Dr.-Ing. dissertation, Friedrich-Alexander-Universität Erlangen-Nürnberg, May 2017. Third edition (Nov. 2017).

S. Bosse, C. R. Helmrich, H. Schwarz, D. Marpe, and T. Wiegand, «Perceptually Optimized QP Adaptation and Associated Distortion Measure», document JVET-H0047, Macau, Oct. 2017. Zip file (Dec. 2017).

2016

C. R. Helmrich and B. Edler, «Signal-Adaptive Switching of Overlap Ratio in Audio Transform Coding», in Proc. IEEE ICASSP, Shanghai, pp. 639–643, Mar. 2016. Paper.

C. R. Helmrich and B. Edler, «Audio Coding Using Overlap and Kernel Adaptation», IEEE Signal Processing Letters, vol. 23, no. 5, pp. 590–594, May 2016. Article manuscript, article.

C. R. Helmrich, R. Füg, and B. Edler, «Frequency-Domain Prediction for Audio Coding», submitted to IEEE Signal Processing Letters, Aug. 2016. Article manuscript.

F. Schuh, S. Dick, R. Füg, C. R. Helmrich, N. Rettelbach, and T. Schwegler, «Efficient Multichannel Audio Transform Coding with Low Delay and Complexity», in Proc. AES 141^st Convention, Los Angeles, preprint 9660, Oct. 2016. Paper.

S. Disch, A. Niedermeier, C. R. Helmrich, C. Neukam, K. Schmidt, R. Geiger, J. Lecomte, F. Ghido, F. Nagel, and B. Edler, «Intelligent Gap Filling in Perceptual Transform Coding of Audio», in Proc. AES 141^st Convention, Los Angeles, preprint 9661, Oct. 2016. Paper.

2015

C. Helmrich, A. Niedermeier, S. Disch, and F. Ghido, «Spectral Envelope Reconstruction via IGF for Audio Transform Coding», in Proc. IEEE ICASSP, Brisbane, pp. 389–393, Apr. 2015. Paper.

T. Bäckström and C. R. Helmrich, «Arithmetic Coding of Speech and Audio Spectra Using TCX Based on Linear Predictive Spectral Envelopes», in Proc. IEEE ICASSP, Brisbane, pp. 5127–5131, Apr. 2015. Paper.

G. Fuchs, C. R. Helmrich, G. Marković, M. Neusinger, E. Ravelli, and T. Moriya, «Low Delay LPC and MDCT-Based Audio Coding in the EVS Codec», in Proc. IEEE ICASSP, Brisbane, pp. 5723–5727, Apr. 2015. Paper.

E. Ravelli, C. R. Helmrich, G. Fuchs, and M. Multrus, «Low-Complexity and Robust Coding Mode Decision in the EVS Coder», in Proc. IEEE ICASSP, Brisbane, pp. 5888–5892, Apr. 2015. Paper.

T. Moriya, Y. Kamamoto, N. Harada, T. Bäckström, C. R. Helmrich, and G. Fuchs, «Harmonic Model for MDCT Based Audio Coding with LPC Envelope», in Proc. EURASIP 23^rd EUSIPCO, Nice, pp. 794–798, Sep. 2015. Paper.

C. R. Helmrich, A. Niedermeier, S. Bayer, and B. Edler, «Low-Complexity Semi-Parametric Joint-Stereo Audio Transform Coding», in Proc. EURASIP 23^rd EUSIPCO, Nice, pp. 799–803, Sep. 2015. Paper.

C. R. Helmrich and B. Edler, «Signal-Adaptive Transform Kernel Switching for Stereo Audio Coding», in Proc. IEEE Workshop on Applic. of Signal Processing to Audio and Acoustics (WASPAA), New Paltz, pp. 1–5, Oct. 2015. Paper.

C. R. Helmrich and M. Fischer, «Low-Delay Transform Coding Using the MPEG-H Audio Codec», in Proc. AES 139^th Convention, New York, preprint 9355, Oct. 2015. Paper.

2014

C. R. Helmrich, G. Marković, and B. Edler, «Improved Low-Delay MDCT-Based Coding of Both Stationary and Transient Audio Signals», in Proc. IEEE ICASSP, Florence, Italy, pp. 6954–6958, May 2014. Paper.

2013

M. Neuendorf, M. Multrus, N. Rettelbach, G. Fuchs, J. Robilliard, J. Lecomte, S. Wilde, S. Bayer, S. Disch, C. R. Helmrich, R. Lefebvre, P. Gournay, B. Bessette, J. Lapierre, K. Kjörling, H. Purnhagen, L. Villemoes, W. Oomen, E. Schuijers, K. Kikuiri, T. Chinen, T. Norimatsu, K.-S. Chong, E. Oh, M. Kim, S. Quackenbush, and B. Grill, «The ISO/MPEG Unified Speech and Audio Coding Standard—Consistent High Quality for All Content Types and at All Bitrates», Journal of the AES, vol. 61, no. 12, pp. 956–977, Dec. 2013. Article.

2012

M. Neuendorf, M. Multrus, N. Rettelbach, G. Fuchs, J. Robilliard, J. Lecomte, S. Wilde, S. Bayer, S. Disch, C. R. Helmrich, R. Lefebvre, P. Gournay, B. Bessette, J. Lapierre, K. Kjörling, H. Purnhagen, L. Villemoes, W. Oomen, E. Schuijers, K. Kikuiri, T. Chinen, T. Norimatsu, K.-S. Chong, E. Oh, M. Kim, S. Quackenbush, and B. Grill, «MPEG Unified Speech and Audio Coding—The ISO/MPEG Standard for High-Efficiency Audio Coding of All Content Types», in Proc. AES 132^nd Convention, Budapest, preprint 8654, Apr. 2012. Paper.

2011

C. R. Helmrich, P. Carlsson, S. Disch, B. Edler, J. Hilpert, M. Neusinger, H. Purnhagen, N. Rettelbach, J. Robilliard, and L. Villemoes, «Efficient Transform Coding of Two-Channel Audio Signals by Means of Complex-Valued Stereo Prediction», in Proc. IEEE ICASSP, Prague, pp. 497–500, May 2011. Paper.

2010

C. R. Helmrich, «On the Use of Sums of Sines in the Design of Signal Windows», in Proc. DAFx-10, Graz, poster session 8, Sep. 2010. Paper.

2008

M. Holters, C. R. Helmrich, and U. Zölzer, «Delay-Free Audio Coding Based on ADPCM and Error Feedback», in Proc. DAFx-08, Espoo, paper session 2d, Sep. 2008. Paper.

2007

C. R. Helmrich, M. Holters, and U. Zölzer, «Improved Psychoacoustic Noise Shaping for Requantization of High-Resolution Digital Audio», in Proc. AES 31^st Int. Conf., London, June 2007. Paper manuscript, paper.

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