{"id":2005,"date":"2020-01-20T18:18:00","date_gmt":"2020-01-20T16:18:00","guid":{"rendered":"https:\/\/alax.info\/blog\/?p=2005"},"modified":"2020-01-20T18:41:07","modified_gmt":"2020-01-20T16:41:07","slug":"telegram-bot-to-extract-contents-of-h-264-parameter-set-nal-units","status":"publish","type":"post","link":"https:\/\/alax.info\/blog\/2005","title":{"rendered":"Telegram bot to extract contents of H.264 parameter set NAL units"},"content":{"rendered":"\n

In continuation of previous post about C++\/WinRT and Telegram<\/a>, here we with @ParameterSetAnalyzeBot<\/a>: “Your buddy to extract H.264 parameter set NAL data”. In a chat, it expects an MP4 file with an H.264 video track sent him (her?). Then it extracts data from sample description box and deciphers into readable form:<\/p>\n\n\n\n

\"\"<\/figure>\n\n\n\n

It’s literally taking the MP4 file to the Media Foundation Source Reader API<\/a>, pulls MF_MT_MPEG_SEQUENCE_HEADER<\/a><\/code> and pipe the data to h264_analyze<\/a><\/code> tool (my fork of it has Visual Studio 2019 project, and is added ability to take input from stdin<\/code> for piping needs).<\/p>\n\n\n\n

It will probably not be online forever, but it’s live. Be aware that Telegram limits file transmissions to 20 MB per file<\/a> at the moment.<\/p>\n\n\n\n\n\n\n\n

!! Found NAL at offset 3 (0x0003), size 31 (0x001F) \n 0.8: forbidden_zero_bit: 0 \n 0.7: nal->nal_ref_idc: 3 \n 0.5: nal->nal_unit_type: 7 \n 1.8: sps->profile_idc: 77 \n 2.8: sps->constraint_set0_flag: 0 \n 2.7: sps->constraint_set1_flag: 0 \n 2.6: sps->constraint_set2_flag: 0 \n 2.5: sps->constraint_set3_flag: 0 \n 2.4: sps->constraint_set4_flag: 0 \n 2.3: sps->constraint_set5_flag: 0 \n 2.2: reserved_zero_2bits: 0 \n 3.8: sps->level_idc: 31 \n 4.8: sps->seq_parameter_set_id: 0 \n 4.7: sps->log2_max_frame_num_minus4: 3 \n 4.2: sps->pic_order_cnt_type: 0 \n 4.1: sps->log2_max_pic_order_cnt_lsb_minus4: 0 \n 5.8: sps->num_ref_frames: 4 \n 5.3: sps->gaps_in_frame_num_value_allowed_flag: 0 \n 5.2: sps->pic_width_in_mbs_minus1: 79 \n 7.5: sps->pic_height_in_map_units_minus1: 44 \n 8.2: sps->frame_mbs_only_flag: 1 \n 8.1: sps->direct_8x8_inference_flag: 1 \n 9.8: sps->frame_cropping_flag: 0 \n 9.7: sps->vui_parameters_present_flag: 1 \n 9.6: sps->vui.aspect_ratio_info_present_flag: 1 \n 9.5: sps->vui.aspect_ratio_idc: 255 \n 10.5: sps->vui.sar_width: 1 \n 12.5: sps->vui.sar_height: 1 \n 14.5: sps->vui.overscan_info_present_flag: 0 \n 14.4: sps->vui.video_signal_type_present_flag: 1 \n 14.3: sps->vui.video_format: 0 \n 15.8: sps->vui.video_full_range_flag: 0 \n 15.7: sps->vui.colour_description_present_flag: 0 \n 15.6: sps->vui.chroma_loc_info_present_flag: 0 \n 15.5: sps->vui.timing_info_present_flag: 1 \n 15.4: sps->vui.num_units_in_tick: 1 \n 19.4: sps->vui.time_scale: 50 \n 23.4: sps->vui.fixed_frame_rate_flag: 1 \n 23.3: sps->vui.nal_hrd_parameters_present_flag: 0 \n 23.2: sps->vui.vcl_hrd_parameters_present_flag: 0 \n 23.1: sps->vui.pic_struct_present_flag: 0 \n 24.8: sps->vui.bitstream_restriction_flag: 1 \n 24.7: sps->vui.motion_vectors_over_pic_boundaries_flag: 1 \n 24.6: sps->vui.max_bytes_per_pic_denom: 2 \n 24.3: sps->vui.max_bits_per_mb_denom: 1 \n 25.8: sps->vui.log2_max_mv_length_horizontal: 16 \n 26.7: sps->vui.log2_max_mv_length_vertical: 16 \n 27.6: sps->vui.num_reorder_frames: 0 \n 27.5: sps->vui.max_dec_frame_buffering: 4 \n 28.8: rbsp_stop_one_bit: 1 \n 28.7: rbsp_alignment_zero_bit: 0 \n 28.6: rbsp_alignment_zero_bit: 0 \n 28.5: rbsp_alignment_zero_bit: 0 \n 28.4: rbsp_alignment_zero_bit: 0 \n 28.3: rbsp_alignment_zero_bit: 0 \n 28.2: rbsp_alignment_zero_bit: 0 \n 28.1: rbsp_alignment_zero_bit: 0 \n!! Found NAL at offset 37 (0x0025), size 4 (0x0004) \n 0.8: forbidden_zero_bit: 0 \n 0.7: nal->nal_ref_idc: 3 \n 0.5: nal->nal_unit_type: 8 \n 1.8: pps->pic_parameter_set_id: 0 \n 1.7: pps->seq_parameter_set_id: 0 \n 1.6: pps->entropy_coding_mode_flag: 1 \n 1.5: pps->pic_order_present_flag: 0 \n 1.4: pps->num_slice_groups_minus1: 0 \n 1.3: pps->num_ref_idx_l0_active_minus1: 0 \n 1.2: pps->num_ref_idx_l1_active_minus1: 0 \n 1.1: pps->weighted_pred_flag: 0 \n 2.8: pps->weighted_bipred_idc: 0 \n 2.6: pps->pic_init_qp_minus26: 0 \n 2.5: pps->pic_init_qs_minus26: 0 \n 2.4: pps->chroma_qp_index_offset: 0 \n 2.3: pps->deblocking_filter_control_present_flag: 0 \n 2.2: pps->constrained_intra_pred_flag: 0 \n 2.1: pps->redundant_pic_cnt_present_flag: 0 \n 3.8: rbsp_stop_one_bit: 1 \n 3.7: rbsp_alignment_zero_bit: 0 \n 3.6: rbsp_alignment_zero_bit: 0 \n 3.5: rbsp_alignment_zero_bit: 0 \n 3.4: rbsp_alignment_zero_bit: 0 \n 3.3: rbsp_alignment_zero_bit: 0 \n 3.2: rbsp_alignment_zero_bit: 0 \n 3.1: rbsp_alignment_zero_bit: 0<\/pre>\n\n\n\n
Maybe it is worth adding full Media Foundation attribute printout as well, and similar H.265\/HEVC data. This will have to wait for next occasion though.<\/p>\n\n\n\n
And – yeah – it does have support for fragmented MP4 too:<\/p>\n\n\n\n
\"\"<\/a><\/figure>\n","protected":false},"excerpt":{"rendered":"
In continuation of previous post about C++\/WinRT and Telegram, here we with @ParameterSetAnalyzeBot: “Your buddy to extract H.264 parameter set NAL data”. In a chat, it expects an MP4 file with an H.264 video track sent him (her?). Then it extracts data from sample description box and deciphers into readable form: It’s literally taking the… <\/p>\n
Read the full article<\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[105,379,592,486],"class_list":["post-2005","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-bot","tag-h-264","tag-telegram","tag-video"],"_links":{"self":[{"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/posts\/2005","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/comments?post=2005"}],"version-history":[{"count":0,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/posts\/2005\/revisions"}],"wp:attachment":[{"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/media?parent=2005"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/categories?post=2005"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/alax.info\/blog\/wp-json\/wp\/v2\/tags?post=2005"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}