{"about":{"site":"https://codewithpapers.app","non_affiliation":"Code with Papers and Syntology are not affiliated with, endorsed by, or sponsored by Papers with Code, Meta, or the pwc-archive mirror.","licence":"CC BY-SA 4.0","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","attribution":"https://codewithpapers.app/attribution","modified":"archive material modified by Syntology; see the attribution page"},"url":"/paper/bidirectional-decoding-improving-action","title":"Bidirectional Decoding: Improving Action Chunking via Guided Test-Time Sampling","arxiv_id":"2408.17355","date":"2024-08-30","proceeding":null,"authors":["Yuejiang Liu","Jubayer Ibn Hamid","Annie Xie","Yoonho Lee","Maximilian Du","Chelsea Finn"],"abstract":"Predicting and executing a sequence of actions without intermediate replanning, known as action chunking, is increasingly used in robot learning from human demonstrations. Yet, its effects on the learned policy remain inconsistent: some studies find it crucial for achieving strong results, while others observe decreased performance. In this paper, we first dissect how action chunking impacts the divergence between a learner and a demonstrator. We find that action chunking allows the learner to better capture the temporal dependencies in demonstrations but at the cost of reduced reactivity to unexpected states. To address this tradeoff, we propose Bidirectional Decoding (BID), a test-time inference algorithm that bridges action chunking with closed-loop adaptation. At each timestep, BID samples multiple candidate predictions and searches for the optimal one based on two criteria: (i) backward coherence, which favors samples that align with previous decisions; (ii) forward contrast, which seeks samples of high likelihood for future plans. By coupling decisions within and across action chunks, BID promotes both long-term consistency and short-term reactivity. Experimental results show that our method boosts the performance of two state-of-the-art generative policies across seven simulation benchmarks and two real-world tasks. Code and videos are available at https://bid-robot.github.io.","url_abs":"https://arxiv.org/abs/2408.17355v4","url_pdf":"https://arxiv.org/pdf/2408.17355v4.pdf","source":{"archive":"pwc-archive (Hugging Face), CC BY-SA 4.0","snapshot":"2025-07-28","licence_url":"https://creativecommons.org/licenses/by-sa/4.0/legalcode","row_kind":"abstracts"},"code_links":[{"paper_slug":"bidirectional-decoding-improving-action","repo_url":"https://github.com/YuejiangLIU/bid_diffusion","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"pytorch","reach":null},{"paper_slug":"bidirectional-decoding-improving-action","repo_url":"https://github.com/jubayer-hamid/bid_lerobot","is_official":1,"mentioned_in_paper":1,"mentioned_in_github":1,"framework":"pytorch","reach":{"status":"ok","spdx":"Apache-2.0"}}],"tasks":[{"task_slug":"chunking","task_name":"Chunking"}],"methods":[{"method_slug":"align","method_name":"ALIGN"}],"datasets_introduced":[],"methods_introduced":[],"results":[],"syntology":{"syntology_url":"https://syntology.ai/paper/2408.17355","atlas_url":"https://app.syntology.ai/?focus=2408.17355","mcp":{"get_harvested_code_for_paper":{"arxiv_id":"2408.17355"}},"developers":"https://syntology.ai/developers","read_at":"2026-09-25T09:33:49+00:00","read_at_is":"when the build read Syntology's graph, not when any sample ran","claim":"Per-sample execution status on synthesized fixtures; not a correctness claim about the paper. Samples come from repositories linked to the paper, official or community; repo_kind says which.","repos":[{"provenance":"external:paperswithcode_snapshot_2025-07-28","url":"https://github.com/jubayer-hamid/bid_lerobot","reach":{"status":"ok","spdx":"Apache-2.0"}},{"provenance":"external:paperswithcode_snapshot_2025-07-28","url":"https://github.com/YuejiangLIU/bid_diffusion","reach":null}],"summary":{"ran":7,"unverified":7},"by_repo_kind":{"official":{"samples":14,"ran":7,"repositories":2}},"repo_kind_vocabulary":{"official":"The archive marks this repository official for the paper","named_in_paper":"The archive records that the paper mentions this repository; it is not marked official","listed":"In the archive's code links for this paper, not marked official and not recorded as mentioned in the paper","found_in_text":"Syntology found this repository in the paper's own text; whether it is the authors' implementation is not asserted","community":"Not in the archive's code links for this paper; a community repository Syntology harvested"},"n_pointer_only_for_licence":3,"samples":[{"code_sha256_prefix":"96806d7bcd376422","entry":"aggregate_stats","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/datasets/compute_stats.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/datasets/compute_stats.py","link_basis":"first_harvest_node","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"96806d7bcd376422"}},{"code_sha256_prefix":"0ce2ef6e4d74b8e1","entry":"cfg_to_group","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/logger.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/logger.py","link_basis":"first_harvest_node","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"0ce2ef6e4d74b8e1"}},{"code_sha256_prefix":"e2adf71cdd509f3e","entry":"flatten_dict","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/datasets/utils.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/datasets/utils.py","link_basis":"first_harvest_node","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"e2adf71cdd509f3e"}},{"code_sha256_prefix":"34feb637b36db73f","entry":"get_wandb_run_id_from_filesystem","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/logger.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/logger.py","link_basis":"first_harvest_node","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"34feb637b36db73f"}},{"code_sha256_prefix":"099e51f9595e2381","entry":"hf_transform_to_torch","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/datasets/utils.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/datasets/utils.py","link_basis":"first_harvest_node","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"099e51f9595e2381"}},{"code_sha256_prefix":"e6d251290c05dab4","entry":"preprocess_observation","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/envs/utils.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/envs/utils.py","link_basis":"first_harvest_node","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"e6d251290c05dab4"}},{"code_sha256_prefix":"ad190f7467ea58ae","entry":"unflatten_dict","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/datasets/utils.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/datasets/utils.py","link_basis":"first_harvest_node","language":"python","status":"ran","verification_level":1,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"ad190f7467ea58ae"}},{"code_sha256_prefix":"50b733cd61beee6e","entry":"decode_video_frames_torchvision","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/datasets/video_utils.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/datasets/video_utils.py","link_basis":"first_harvest_node","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"50b733cd61beee6e"}},{"code_sha256_prefix":"41456dc6464cef69","entry":"get_image_transforms","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/datasets/transforms.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/datasets/transforms.py","link_basis":"first_harvest_node","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"41456dc6464cef69"}},{"code_sha256_prefix":"08e3707d74a100d9","entry":"load_from_videos","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/datasets/video_utils.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/datasets/video_utils.py","link_basis":"first_harvest_node","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"08e3707d74a100d9"}},{"code_sha256_prefix":"a46ac2680ddd2dbe","entry":"make_env","repo":"jubayer-hamid/bid_lerobot","repo_kind":"official","path":"lerobot/common/envs/factory.py","file_url":"https://github.com/jubayer-hamid/bid_lerobot/blob/HEAD/lerobot/common/envs/factory.py","link_basis":"first_harvest_node","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"Apache-2.0","inline_ok":true,"mcp_get_code":{"code_sha256":"a46ac2680ddd2dbe"}},{"code_sha256_prefix":"597482ebd2495227","entry":"postprocess_action_batch","repo":"YuejiangLIU/bid_diffusion","repo_kind":"official","path":"diffusion_policy/sampler/base.py","file_url":"https://github.com/YuejiangLIU/bid_diffusion/blob/HEAD/diffusion_policy/sampler/base.py","link_basis":"first_harvest_node","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"NOASSERTION","inline_ok":false,"mcp_get_code":{"code_sha256":"597482ebd2495227"}},{"code_sha256_prefix":"e1f5a88e179e4f79","entry":"preprocess_obs_batch","repo":"YuejiangLIU/bid_diffusion","repo_kind":"official","path":"diffusion_policy/sampler/base.py","file_url":"https://github.com/YuejiangLIU/bid_diffusion/blob/HEAD/diffusion_policy/sampler/base.py","link_basis":"first_harvest_node","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"NOASSERTION","inline_ok":false,"mcp_get_code":{"code_sha256":"e1f5a88e179e4f79"}},{"code_sha256_prefix":"205ee75fa1a06a47","entry":"slice_action_batch","repo":"YuejiangLIU/bid_diffusion","repo_kind":"official","path":"diffusion_policy/sampler/base.py","file_url":"https://github.com/YuejiangLIU/bid_diffusion/blob/HEAD/diffusion_policy/sampler/base.py","link_basis":"first_harvest_node","language":"python","status":"unverified","verification_level":0,"contract_check":null,"metamorphic_tier":null,"behaviour_fingerprint":false,"licence":"NOASSERTION","inline_ok":false,"mcp_get_code":{"code_sha256":"205ee75fa1a06a47"}}]},"arxiv_metadata":null,"syntology_extracted_results":null}