最近在解决HLS的EXT-X-STREAM-INF信息中显示CODECS信息的时候遇到了解析HEVC的NALUnit的问题，经过与赵军聊过后，发现使用ffmpeg的bitstream filter的trace_headers参数可以很有效率的解决分析NALU的问题，很方便，所以大概总结一下分享给大家。
首先我们了解一下 trace_headers 的基础信息，看一下官方文档的说明：
Log trace output containing all syntax elements in
the coded stream headers (everything above the level of
individual coded blocks). This can be useful for debugging
low-level stream issues.
Supports AV1, H.264, H.265, (M)JPEG, MPEG-2 and VP9,
but depending on the build only a subset of these may be
available.翻译一下内容：
日志跟踪输出，其中包含编码流标头中的所有语法元素
（高于单个编码块级别的所有元素）。
这对于调试低级流问题很有用。
支持AV1，H.264，H.265，（M）JPEG，MPEG-2和VP9，
但根据内部版本，可能只有其中一部分可用。大概意思已经很明显了，虽然翻译得不是很好，但是应该足够获得需要的信息了，那么接下来可以尝试着确认一下：
命令行如下：
./ffmpeg -i input.mp4 -c copy -bsf:v trace_headers -y output.mp4这是一个只有 2 帧的 hevc 的 input.mp4 视频文件，然后通过 codec copy 的方式将编码数据存入 output.mp4 中，输出的信息如下：
ffmpeg version N-99816-g3da35b7cc7 Copyright (c) 2000-2020 the FFmpeg developers
built with Apple LLVM version 10.0.0 (clang-1000.11.45.5)
configuration: --enable-fontconfig --enable-gpl --enable-libass --enable-libbluray --enable-libfreetype --enable-libmp3lame --enable-libspeex --enable-libx264 --enable-libx265 --enable-libfdk-aac --enable-version3 --enable-nonfree --enable-videotoolbox --enable-libxml2 --samples=fate-suite/ --enable-libopencv --enable-libopus --enable-opengl --enable-libzmq --disable-optimizations --disable-stripping
libavutil 56. 60.100 / 56. 60.100
libavcodec 58.112.100 / 58.112.100
libavformat 58. 64.100 / 58. 64.100
libavdevice 58. 11.102 / 58. 11.102
libavfilter 7. 88.100 / 7. 88.100
libswscale 5. 8.100 / 5. 8.100
libswresample 3. 8.100 / 3. 8.100
libpostproc 55. 8.100 / 55. 8.100
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'input.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf58.35.100
Duration: 00:00:00.08, start: 0.000000, bitrate: 295 kb/s
Stream #0:0(und): Video: hevc (Main) (hev1 / 0x31766568), yuv420p(tv, progressive), 176x144 [SAR 1:1 DAR 11:9], 6 kb/s, 25 fps, 25 tbr, 12800 tbn, 25 tbc (default)
Metadata:
handler_name : VideoHandler
[trace_headers @ 0x7fb8d9603a00] Extradata
[trace_headers @ 0x7fb8d9603a00] Video Parameter Set
[trace_headers @ 0x7fb8d9603a00] 0 forbidden_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 1 nal_unit_type 100000 = 32
[trace_headers @ 0x7fb8d9603a00] 7 nuh_layer_id 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 13 nuh_temporal_id_plus1 001 = 1
[trace_headers @ 0x7fb8d9603a00] 16 vps_video_parameter_set_id 0000 = 0
[trace_headers @ 0x7fb8d9603a00] 20 vps_base_layer_internal_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 21 vps_base_layer_available_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 22 vps_max_layers_minus1 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 28 vps_max_sub_layers_minus1 000 = 0
[trace_headers @ 0x7fb8d9603a00] 31 vps_temporal_id_nesting_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 32 vps_reserved_0xffff_16bits 1111111111111111 = 65535
[trace_headers @ 0x7fb8d9603a00] 48 general_profile_space 00 = 0
[trace_headers @ 0x7fb8d9603a00] 50 general_tier_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 51 general_profile_idc 00001 = 1
[trace_headers @ 0x7fb8d9603a00] 56 general_profile_compatibility_flag[0] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 57 general_profile_compatibility_flag[1] 1 = 1
[trace_headers @ 0x7fb8d9603a00] 58 general_profile_compatibility_flag[2] 1 = 1
[trace_headers @ 0x7fb8d9603a00] 59 general_profile_compatibility_flag[3] 0 = 0
为了节省篇幅干掉了好多内容，自己脑补吧。
[trace_headers @ 0x7fb8d9603a00] 84 general_profile_compatibility_flag[28] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 85 general_profile_compatibility_flag[29] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 86 general_profile_compatibility_flag[30] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 87 general_profile_compatibility_flag[31] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 88 general_progressive_source_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 89 general_interlaced_source_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 90 general_non_packed_constraint_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 91 general_frame_only_constraint_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 92 general_reserved_zero_7bits 0000000 = 0
[trace_headers @ 0x7fb8d9603a00] 99 general_one_picture_only_constraint_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 100 general_reserved_zero_35bits 000000000000000000000000 = 0
[trace_headers @ 0x7fb8d9603a00] 124 general_reserved_zero_35bits 00000000000 = 0
[trace_headers @ 0x7fb8d9603a00] 135 general_inbld_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 136 general_level_idc 00111100 = 60
[trace_headers @ 0x7fb8d9603a00] 144 vps_sub_layer_ordering_info_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 145 vps_max_dec_pic_buffering_minus1[0] 00101 = 4
[trace_headers @ 0x7fb8d9603a00] 150 vps_max_num_reorder_pics[0] 011 = 2
[trace_headers @ 0x7fb8d9603a00] 153 vps_max_latency_increase_plus1[0] 00110 = 5
[trace_headers @ 0x7fb8d9603a00] 158 vps_max_layer_id 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 164 vps_num_layer_sets_minus1 1 = 0
[trace_headers @ 0x7fb8d9603a00] 165 vps_timing_info_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 166 vps_extension_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 167 rbsp_stop_one_bit 1 = 1
[trace_headers @ 0x7fb8d9603a00] Sequence Parameter Set
[trace_headers @ 0x7fb8d9603a00] 0 forbidden_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 1 nal_unit_type 100001 = 33
[trace_headers @ 0x7fb8d9603a00] 7 nuh_layer_id 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 13 nuh_temporal_id_plus1 001 = 1
[trace_headers @ 0x7fb8d9603a00] 16 sps_video_parameter_set_id 0000 = 0
[trace_headers @ 0x7fb8d9603a00] 20 sps_max_sub_layers_minus1 000 = 0
[trace_headers @ 0x7fb8d9603a00] 23 sps_temporal_id_nesting_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 24 general_profile_space 00 = 0
[trace_headers @ 0x7fb8d9603a00] 26 general_tier_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 27 general_profile_idc 00001 = 1
[trace_headers @ 0x7fb8d9603a00] 32 general_profile_compatibility_flag[0] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 33 general_profile_compatibility_flag[1] 1 = 1
[trace_headers @ 0x7fb8d9603a00] 34 general_profile_compatibility_flag[2] 1 = 1
[trace_headers @ 0x7fb8d9603a00] 35 general_profile_compatibility_flag[3] 0 = 0
为了节省篇幅，干掉了好多，自己脑补吧。
[trace_headers @ 0x7fb8d9603a00] 57 general_profile_compatibility_flag[25] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 58 general_profile_compatibility_flag[26] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 59 general_profile_compatibility_flag[27] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 60 general_profile_compatibility_flag[28] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 61 general_profile_compatibility_flag[29] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 62 general_profile_compatibility_flag[30] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 63 general_profile_compatibility_flag[31] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 64 general_progressive_source_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 65 general_interlaced_source_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 66 general_non_packed_constraint_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 67 general_frame_only_constraint_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 68 general_reserved_zero_7bits 0000000 = 0
[trace_headers @ 0x7fb8d9603a00] 75 general_one_picture_only_constraint_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 76 general_reserved_zero_35bits 000000000000000000000000 = 0
[trace_headers @ 0x7fb8d9603a00] 100 general_reserved_zero_35bits 00000000000 = 0
[trace_headers @ 0x7fb8d9603a00] 111 general_inbld_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 112 general_level_idc 00111100 = 60
[trace_headers @ 0x7fb8d9603a00] 120 sps_seq_parameter_set_id 1 = 0
[trace_headers @ 0x7fb8d9603a00] 121 chroma_format_idc 010 = 1
[trace_headers @ 0x7fb8d9603a00] 124 pic_width_in_luma_samples 000000010110001 = 176
[trace_headers @ 0x7fb8d9603a00] 139 pic_height_in_luma_samples 000000010010001 = 144
[trace_headers @ 0x7fb8d9603a00] 154 conformance_window_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 155 bit_depth_luma_minus8 1 = 0
[trace_headers @ 0x7fb8d9603a00] 156 bit_depth_chroma_minus8 1 = 0
[trace_headers @ 0x7fb8d9603a00] 157 log2_max_pic_order_cnt_lsb_minus4 00101 = 4
[trace_headers @ 0x7fb8d9603a00] 162 sps_sub_layer_ordering_info_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 163 sps_max_dec_pic_buffering_minus1[0] 00101 = 4
[trace_headers @ 0x7fb8d9603a00] 168 sps_max_num_reorder_pics[0] 011 = 2
[trace_headers @ 0x7fb8d9603a00] 171 sps_max_latency_increase_plus1[0] 00110 = 5
[trace_headers @ 0x7fb8d9603a00] 176 log2_min_luma_coding_block_size_minus3 1 = 0
[trace_headers @ 0x7fb8d9603a00] 177 log2_diff_max_min_luma_coding_block_size 00100 = 3
[trace_headers @ 0x7fb8d9603a00] 182 log2_min_luma_transform_block_size_minus2 1 = 0
[trace_headers @ 0x7fb8d9603a00] 183 log2_diff_max_min_luma_transform_block_size 00100 = 3
[trace_headers @ 0x7fb8d9603a00] 188 max_transform_hierarchy_depth_inter 1 = 0
[trace_headers @ 0x7fb8d9603a00] 189 max_transform_hierarchy_depth_intra 1 = 0
[trace_headers @ 0x7fb8d9603a00] 190 scaling_list_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 191 amp_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 192 sample_adaptive_offset_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 193 pcm_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 194 num_short_term_ref_pic_sets 1 = 0
[trace_headers @ 0x7fb8d9603a00] 195 long_term_ref_pics_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 196 sps_temporal_mvp_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 197 strong_intra_smoothing_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 198 vui_parameters_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 199 aspect_ratio_info_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 200 aspect_ratio_idc 00000001 = 1
[trace_headers @ 0x7fb8d9603a00] 208 overscan_info_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 209 video_signal_type_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 210 video_format 101 = 5
[trace_headers @ 0x7fb8d9603a00] 213 video_full_range_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 214 colour_description_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 215 chroma_loc_info_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 216 neutral_chroma_indication_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 217 field_seq_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 218 frame_field_info_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 219 default_display_window_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 220 vui_timing_info_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 221 vui_num_units_in_tick 00000000000000000000000000000001 = 1
[trace_headers @ 0x7fb8d9603a00] 253 vui_time_scale 00000000000000000000000000011001 = 25
[trace_headers @ 0x7fb8d9603a00] 285 vui_poc_proportional_to_timing_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 286 vui_hrd_parameters_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 287 bitstream_restriction_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 288 sps_extension_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 289 rbsp_stop_one_bit 1 = 1
[trace_headers @ 0x7fb8d9603a00] 290 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 291 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 292 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 293 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 294 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 295 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] Picture Parameter Set
[trace_headers @ 0x7fb8d9603a00] 0 forbidden_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 1 nal_unit_type 100010 = 34
[trace_headers @ 0x7fb8d9603a00] 7 nuh_layer_id 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 13 nuh_temporal_id_plus1 001 = 1
[trace_headers @ 0x7fb8d9603a00] 16 pps_pic_parameter_set_id 1 = 0
[trace_headers @ 0x7fb8d9603a00] 17 pps_seq_parameter_set_id 1 = 0
[trace_headers @ 0x7fb8d9603a00] 18 dependent_slice_segments_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 19 output_flag_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 20 num_extra_slice_header_bits 000 = 0
[trace_headers @ 0x7fb8d9603a00] 23 sign_data_hiding_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 24 cabac_init_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 25 num_ref_idx_l0_default_active_minus1 1 = 0
[trace_headers @ 0x7fb8d9603a00] 26 num_ref_idx_l1_default_active_minus1 1 = 0
[trace_headers @ 0x7fb8d9603a00] 27 init_qp_minus26 1 = 0
[trace_headers @ 0x7fb8d9603a00] 28 constrained_intra_pred_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 29 transform_skip_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 30 cu_qp_delta_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 31 diff_cu_qp_delta_depth 010 = 1
[trace_headers @ 0x7fb8d9603a00] 34 pps_cb_qp_offset 1 = 0
[trace_headers @ 0x7fb8d9603a00] 35 pps_cr_qp_offset 1 = 0
[trace_headers @ 0x7fb8d9603a00] 36 pps_slice_chroma_qp_offsets_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 37 weighted_pred_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 38 weighted_bipred_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 39 transquant_bypass_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 40 tiles_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 41 entropy_coding_sync_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 42 pps_loop_filter_across_slices_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 43 deblocking_filter_control_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 44 pps_scaling_list_data_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 45 lists_modification_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 46 log2_parallel_merge_level_minus2 1 = 0
[trace_headers @ 0x7fb8d9603a00] 47 slice_segment_header_extension_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 48 pps_extension_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 49 rbsp_stop_one_bit 1 = 1
[trace_headers @ 0x7fb8d9603a00] 50 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 51 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 52 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 53 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 54 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 55 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] Prefix Supplemental Enhancement Information
[trace_headers @ 0x7fb8d9603a00] 0 forbidden_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 1 nal_unit_type 100111 = 39
[trace_headers @ 0x7fb8d9603a00] 7 nuh_layer_id 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 13 nuh_temporal_id_plus1 001 = 1
[trace_headers @ 0x7fb8d9603a00] 16 last_payload_type_byte 00000101 = 5
[trace_headers @ 0x7fb8d9603a00] 24 ff_byte 11111111 = 255
[trace_headers @ 0x7fb8d9603a00] 32 ff_byte 11111111 = 255
[trace_headers @ 0x7fb8d9603a00] 40 ff_byte 11111111 = 255
[trace_headers @ 0x7fb8d9603a00] 48 ff_byte 11111111 = 255
[trace_headers @ 0x7fb8d9603a00] 56 ff_byte 11111111 = 255
[trace_headers @ 0x7fb8d9603a00] 64 ff_byte 11111111 = 255
[trace_headers @ 0x7fb8d9603a00] 72 ff_byte 11111111 = 255
[trace_headers @ 0x7fb8d9603a00] 80 last_payload_size_byte 10101001 = 169
[trace_headers @ 0x7fb8d9603a00] User Data Unregistered
[trace_headers @ 0x7fb8d9603a00] 88 uuid_iso_iec_11578[0] 00101100 = 44
[trace_headers @ 0x7fb8d9603a00] 96 uuid_iso_iec_11578[1] 10100010 = 162
[trace_headers @ 0x7fb8d9603a00] 104 uuid_iso_iec_11578[2] 11011110 = 222
。。。。。。 为了节省篇幅，好多东西干掉了，自己脑补吧。
[trace_headers @ 0x7fb8d9603a00] 15724 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 15725 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 15726 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 15727 rbsp_alignment_zero_bit 0 = 0
Output #0, mp4, to 'output.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf58.64.100
Stream #0:0(und): Video: hevc (Main) (hev1 / 0x31766568), yuv420p(tv, progressive), 176x144 [SAR 1:1 DAR 11:9], q=2-31, 6 kb/s, 25 fps, 25 tbr, 12800 tbn, 12800 tbc (default)
Metadata:
handler_name : VideoHandler
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
[trace_headers @ 0x7fb8d9603a00] Packet: 38 bytes, key frame, pts 0, dts 0, duration 512.
[trace_headers @ 0x7fb8d9603a00] Slice Segment Header
[trace_headers @ 0x7fb8d9603a00] 0 forbidden_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 1 nal_unit_type 010100 = 20
[trace_headers @ 0x7fb8d9603a00] 7 nuh_layer_id 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 13 nuh_temporal_id_plus1 001 = 1
[trace_headers @ 0x7fb8d9603a00] 16 first_slice_segment_in_pic_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 17 no_output_of_prior_pics_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 18 slice_pic_parameter_set_id 1 = 0
[trace_headers @ 0x7fb8d9603a00] 19 slice_type 011 = 2
[trace_headers @ 0x7fb8d9603a00] 22 slice_sao_luma_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 23 slice_sao_chroma_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 24 slice_qp_delta 0001110 = 7
[trace_headers @ 0x7fb8d9603a00] 31 slice_loop_filter_across_slices_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 32 num_entry_point_offsets 011 = 2
[trace_headers @ 0x7fb8d9603a00] 35 offset_len_minus1 00100 = 3
[trace_headers @ 0x7fb8d9603a00] 40 entry_point_offset_minus1[0] 1110 = 14
[trace_headers @ 0x7fb8d9603a00] 44 entry_point_offset_minus1[1] 0110 = 6
[trace_headers @ 0x7fb8d9603a00] 48 alignment_bit_equal_to_one 1 = 1
[trace_headers @ 0x7fb8d9603a00] 49 alignment_bit_equal_to_zero 0 = 0
[trace_headers @ 0x7fb8d9603a00] 50 alignment_bit_equal_to_zero 0 = 0
[trace_headers @ 0x7fb8d9603a00] 51 alignment_bit_equal_to_zero 0 = 0
[trace_headers @ 0x7fb8d9603a00] 52 alignment_bit_equal_to_zero 0 = 0
[trace_headers @ 0x7fb8d9603a00] 53 alignment_bit_equal_to_zero 0 = 0
[trace_headers @ 0x7fb8d9603a00] 54 alignment_bit_equal_to_zero 0 = 0
[trace_headers @ 0x7fb8d9603a00] 55 alignment_bit_equal_to_zero 0 = 0
[trace_headers @ 0x7fb8d9603a00] Packet: 23 bytes, pts 512, dts 512, duration 512.
[trace_headers @ 0x7fb8d9603a00] Slice Segment Header
[trace_headers @ 0x7fb8d9603a00] 0 forbidden_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 1 nal_unit_type 000001 = 1
[trace_headers @ 0x7fb8d9603a00] 7 nuh_layer_id 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 13 nuh_temporal_id_plus1 001 = 1
[trace_headers @ 0x7fb8d9603a00] 16 first_slice_segment_in_pic_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 17 slice_pic_parameter_set_id 1 = 0
[trace_headers @ 0x7fb8d9603a00] 18 slice_type 010 = 1
[trace_headers @ 0x7fb8d9603a00] 21 slice_pic_order_cnt_lsb 00000001 = 1
[trace_headers @ 0x7fb8d9603a00] 29 short_term_ref_pic_set_sps_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 30 num_negative_pics 010 = 1
[trace_headers @ 0x7fb8d9603a00] 33 num_positive_pics 1 = 0
[trace_headers @ 0x7fb8d9603a00] 34 delta_poc_s0_minus1[0] 1 = 0
[trace_headers @ 0x7fb8d9603a00] 35 used_by_curr_pic_s0_flag[0] 1 = 1
[trace_headers @ 0x7fb8d9603a00] 36 slice_temporal_mvp_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 37 slice_sao_luma_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 38 slice_sao_chroma_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 39 num_ref_idx_active_override_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 40 luma_log2_weight_denom 0001000 = 7
[trace_headers @ 0x7fb8d9603a00] 47 delta_chroma_log2_weight_denom 011 = -1
[trace_headers @ 0x7fb8d9603a00] 50 luma_weight_l0_flag[0] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 51 chroma_weight_l0_flag[0] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 52 five_minus_max_num_merge_cand 00100 = 3
[trace_headers @ 0x7fb8d9603a00] 57 slice_qp_delta 0001110 = 7
[trace_headers @ 0x7fb8d9603a00] 64 slice_loop_filter_across_slices_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 65 num_entry_point_offsets 011 = 2
[trace_headers @ 0x7fb8d9603a00] 68 offset_len_minus1 011 = 2
[trace_headers @ 0x7fb8d9603a00] 71 entry_point_offset_minus1[0] 010 = 2
[trace_headers @ 0x7fb8d9603a00] 74 entry_point_offset_minus1[1] 011 = 3
[trace_headers @ 0x7fb8d9603a00] 77 alignment_bit_equal_to_one 1 = 1
[trace_headers @ 0x7fb8d9603a00] 78 alignment_bit_equal_to_zero 0 = 0
[trace_headers @ 0x7fb8d9603a00] 79 alignment_bit_equal_to_zero 0 = 0
frame= 2 fps=0.0 q=-1.0 Lsize= 3kB time=00:00:00.04 bitrate= 592.8kbits/s speed=7.63x
video:0kB audio:0kB subtitle:0kB other streams:0kB global headers:2kB muxing overhead: 4768.852539%
liuqideMBP:clang liuqi$数据比较多，但是当我学习HEVC的解析的时候，这些数据还是需要一个一个位，去解析的，当然，如果只是支持HLS的EXT-X-STREAM-INF中存储CODECS信息的话，只解析Profile、Tier、Level基本上就足够的。也就是最开始那一部分，在参考标准中，Profile、Tier、Level是可以从VPS（Video Parameter Set）中获得、也可以从SPS（Sequence Parameter Set）中获得，考虑到有些编码器不一定带VPS信息，所以只从SPS中读取比较稳妥，然后就可以开启解析SPS的旅程。
从上面输出的内容中，我们可以先拿到SPS部分抽出来单独看：
[trace_headers @ 0x7fb8d9603a00] Sequence Parameter Set
[trace_headers @ 0x7fb8d9603a00] 0 forbidden_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 1 nal_unit_type 100001 = 33
[trace_headers @ 0x7fb8d9603a00] 7 nuh_layer_id 000000 = 0
[trace_headers @ 0x7fb8d9603a00] 13 nuh_temporal_id_plus1 001 = 1
[trace_headers @ 0x7fb8d9603a00] 16 sps_video_parameter_set_id 0000 = 0
[trace_headers @ 0x7fb8d9603a00] 20 sps_max_sub_layers_minus1 000 = 0
[trace_headers @ 0x7fb8d9603a00] 23 sps_temporal_id_nesting_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 24 general_profile_space 00 = 0
[trace_headers @ 0x7fb8d9603a00] 26 general_tier_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 27 general_profile_idc 00001 = 1
[trace_headers @ 0x7fb8d9603a00] 32 general_profile_compatibility_flag[0] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 56 general_profile_compatibility_flag[24] 0 = 0
。。。为了节省篇幅，干掉了好多，自己脑补。
[trace_headers @ 0x7fb8d9603a00] 62 general_profile_compatibility_flag[30] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 63 general_profile_compatibility_flag[31] 0 = 0
[trace_headers @ 0x7fb8d9603a00] 64 general_progressive_source_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 65 general_interlaced_source_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 66 general_non_packed_constraint_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 67 general_frame_only_constraint_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 68 general_reserved_zero_7bits 0000000 = 0
[trace_headers @ 0x7fb8d9603a00] 75 general_one_picture_only_constraint_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 76 general_reserved_zero_35bits 000000000000000000000000 = 0
[trace_headers @ 0x7fb8d9603a00] 100 general_reserved_zero_35bits 00000000000 = 0
[trace_headers @ 0x7fb8d9603a00] 111 general_inbld_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 112 general_level_idc 00111100 = 60
[trace_headers @ 0x7fb8d9603a00] 120 sps_seq_parameter_set_id 1 = 0
[trace_headers @ 0x7fb8d9603a00] 121 chroma_format_idc 010 = 1
[trace_headers @ 0x7fb8d9603a00] 124 pic_width_in_luma_samples 000000010110001 = 176
[trace_headers @ 0x7fb8d9603a00] 139 pic_height_in_luma_samples 000000010010001 = 144
[trace_headers @ 0x7fb8d9603a00] 154 conformance_window_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 155 bit_depth_luma_minus8 1 = 0
[trace_headers @ 0x7fb8d9603a00] 156 bit_depth_chroma_minus8 1 = 0
[trace_headers @ 0x7fb8d9603a00] 157 log2_max_pic_order_cnt_lsb_minus4 00101 = 4
[trace_headers @ 0x7fb8d9603a00] 162 sps_sub_layer_ordering_info_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 163 sps_max_dec_pic_buffering_minus1[0] 00101 = 4
[trace_headers @ 0x7fb8d9603a00] 168 sps_max_num_reorder_pics[0] 011 = 2
[trace_headers @ 0x7fb8d9603a00] 171 sps_max_latency_increase_plus1[0] 00110 = 5
[trace_headers @ 0x7fb8d9603a00] 176 log2_min_luma_coding_block_size_minus3 1 = 0
[trace_headers @ 0x7fb8d9603a00] 177 log2_diff_max_min_luma_coding_block_size 00100 = 3
[trace_headers @ 0x7fb8d9603a00] 182 log2_min_luma_transform_block_size_minus2 1 = 0
[trace_headers @ 0x7fb8d9603a00] 183 log2_diff_max_min_luma_transform_block_size 00100 = 3
[trace_headers @ 0x7fb8d9603a00] 188 max_transform_hierarchy_depth_inter 1 = 0
[trace_headers @ 0x7fb8d9603a00] 189 max_transform_hierarchy_depth_intra 1 = 0
[trace_headers @ 0x7fb8d9603a00] 190 scaling_list_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 191 amp_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 192 sample_adaptive_offset_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 193 pcm_enabled_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 194 num_short_term_ref_pic_sets 1 = 0
[trace_headers @ 0x7fb8d9603a00] 195 long_term_ref_pics_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 196 sps_temporal_mvp_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 197 strong_intra_smoothing_enabled_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 198 vui_parameters_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 199 aspect_ratio_info_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 200 aspect_ratio_idc 00000001 = 1
[trace_headers @ 0x7fb8d9603a00] 208 overscan_info_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 209 video_signal_type_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 210 video_format 101 = 5
[trace_headers @ 0x7fb8d9603a00] 213 video_full_range_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 214 colour_description_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 215 chroma_loc_info_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 216 neutral_chroma_indication_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 217 field_seq_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 218 frame_field_info_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 219 default_display_window_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 220 vui_timing_info_present_flag 1 = 1
[trace_headers @ 0x7fb8d9603a00] 221 vui_num_units_in_tick 00000000000000000000000000000001 = 1
[trace_headers @ 0x7fb8d9603a00] 253 vui_time_scale 00000000000000000000000000011001 = 25
[trace_headers @ 0x7fb8d9603a00] 285 vui_poc_proportional_to_timing_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 286 vui_hrd_parameters_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 287 bitstream_restriction_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 288 sps_extension_present_flag 0 = 0
[trace_headers @ 0x7fb8d9603a00] 289 rbsp_stop_one_bit 1 = 1
[trace_headers @ 0x7fb8d9603a00] 290 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 291 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 292 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 293 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 294 rbsp_alignment_zero_bit 0 = 0
[trace_headers @ 0x7fb8d9603a00] 295 rbsp_alignment_zero_bit 然后拿出参考标准对比着看一下内容：
解析的顺序如下：
解析的时候需要注意几个点，就是处理文件中的数据位RBSP先，也就是处理0x000003，而处理RBSP的相关操作在参考标准中也有详细的说明：
如果看不懂的话，可以翻开参考标准，找到对应的章节，然后用google翻译翻译一下，或者有道翻译也行。
好了，HEVC 的 profile、tier、level 的解析到这里应该就可以搞定了，解析出来后，怎么存呢？需要看一下HLS怎么说的，因为只看RFC8216的话，理解起来可能稍微麻烦一些，所以苹果给出了参考例子：
参考链接如下：
https://developer.apple.com/documentation/http_live_streaming/hls_authoring_specification_for_apple_devices/hls_authoring_specification_for_apple_devices_appendixes
直接跳到Example Playlist一节：
The following is an example of a playlist with Dolby Vision, HDR10, and SDR content at resolutions from 720p to 4K.
#EXTM3U
#EXT-X-VERSION:7
#EXT-X-INDEPENDENT-SEGMENTS
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=2778321,BANDWIDTH=3971374,VIDEO-RANGE=SDR,CODECS="hvc1.2.4.L123.B0",RESOLUTION=1280x720,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=NONE
sdr_720/prog_index.m3u8
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=6759875,BANDWIDTH=10022043,VIDEO-RANGE=SDR,CODECS="hvc1.2.4.L123.B0",RESOLUTION=1920x1080,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=TYPE-0
sdr_1080/prog_index.m3u8
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=20985770,BANDWIDTH=28058971,VIDEO-RANGE=SDR,CODECS="hvc1.2.4.L150.B0",RESOLUTION=3840x2160,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=TYPE-1
sdr_2160/prog_index.m3u8
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=3385450,BANDWIDTH=5327059,VIDEO-RANGE=PQ,CODECS="dvh1.05.01",RESOLUTION=1280x720,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=NONE
dolby_720/prog_index.m3u8
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=7999361,BANDWIDTH=12876596,VIDEO-RANGE=PQ,CODECS="dvh1.05.03",RESOLUTION=1920x1080,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=TYPE-0
dolby_1080/prog_index.m3u8
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=24975091,BANDWIDTH=30041698,VIDEO-RANGE=PQ,CODECS="dvh1.05.06",RESOLUTION=3840x2160,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=TYPE-1
dolby_2160/prog_index.m3u8
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=3320040,BANDWIDTH=5280654,VIDEO-RANGE=PQ,CODECS="hvc1.2.4.L123.B0",RESOLUTION=1280x720,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=NONE
hdr10_720/prog_index.m3u8
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=7964551,BANDWIDTH=12886714,VIDEO-RANGE=PQ,CODECS="hvc1.2.4.L123.B0",RESOLUTION=1920x1080,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=TYPE-0
hdr10_1080/prog_index.m3u8
#EXT-X-STREAM-INF:AVERAGE-BANDWIDTH=24833402,BANDWIDTH=29983769,VIDEO-RANGE=PQ,CODECS="hvc1.2.4.L150.B0",RESOLUTION=3840x2160,FRAME-RATE=23.976,CLOSED-CAPTIONS=NONE,HDCP-LEVEL=TYPE-1
hdr10_2160/prog_index.m3u8
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=248586,BANDWIDTH=593626,VIDEO-RANGE=SDR,CODECS="hvc1.2.4.L123.B0",RESOLUTION=1280x720,HDCP-LEVEL=NONE,URI="sdr_720/iframe_index.m3u8"
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=399790,BANDWIDTH=956552,VIDEO-RANGE=SDR,CODECS="hvc1.2.4.L123.B0",RESOLUTION=1920x1080,HDCP-LEVEL=TYPE-0,URI="sdr_1080/iframe_index.m3u8"
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=826971,BANDWIDTH=1941397,VIDEO-RANGE=SDR,CODECS="hvc1.2.4.L150.B0",RESOLUTION=3840x2160,HDCP-LEVEL=TYPE-1,URI="sdr_2160/iframe_index.m3u8"
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=232253,BANDWIDTH=573073,VIDEO-RANGE=PQ,CODECS="dvh1.05.01",RESOLUTION=1280x720,HDCP-LEVEL=NONE,URI="dolby_720/iframe_index.m3u8"
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=365337,BANDWIDTH=905037,VIDEO-RANGE=PQ,CODECS="dvh1.05.03",RESOLUTION=1920x1080,HDCP-LEVEL=TYPE-0,URI="dolby_1080/iframe_index.m3u8"
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=739114,BANDWIDTH=1893236,VIDEO-RANGE=PQ,CODECS="dvh1.05.06",RESOLUTION=3840x2160,HDCP-LEVEL=TYPE-1,URI="dolby_2160/iframe_index.m3u8"
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=232511,BANDWIDTH=572673,VIDEO-RANGE=PQ,CODECS="hvc1.2.4.L123.B0",RESOLUTION=1280x720,HDCP-LEVEL=NONE,URI="hdr10_720/iframe_index.m3u8"
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=364552,BANDWIDTH=905053,VIDEO-RANGE=PQ,CODECS="hvc1.2.4.L123.B0",RESOLUTION=1920x1080,HDCP-LEVEL=TYPE-0,URI="hdr10_1080/iframe_index.m3u8"
#EXT-X-I-FRAME-STREAM-INF:AVERAGE-BANDWIDTH=739757,BANDWIDTH=1895477,VIDEO-RANGE=PQ,CODECS="hvc1.2.4.L150.B0",RESOLUTION=3840x2160,HDCP-LEVEL=TYPE-1,URI="hdr10_2160/iframe_index.m3u8"
The HEVC codec values are described in ISO/IEC 14496-15.
A short description is
"Codec.Profile.Flags.TierLevel.Constraints",
so in hvc1.2.4.L123.B0,
the 2 means Main 10 profile,
and the L123 means normal tier, level 4.1.
The Dolby Video codec values are described in
Dolby Vision streams within the HTTP Live Streaming
format v1.1. A short description is Codec.Profile.Level,
so in dvh1.05.03 the Profile is 5 and the Level is 3.上面的信息中能够看到有相关的解释，重点是最后两段。
CODECS信息展示的顺序为“Codec.Profile.Flags.TierLevel.Constraints”
从example的例子可以拿出来看到是这样：”hvc1.2.4.L150.B0″
而从最开始我们的input文件中拿到的信息，应该是这样”hvc1.1.4.L60.B01″
因为profile和level读到的值是这样：
[trace_headers @ 0x7fb8d9603a00] 27 general_profile_idc 00001 = 1
[trace_headers @ 0x7fb8d9603a00] 112 general_level_idc 所以代码实现是这样：
if (st->codecpar->codec_id == AV_CODEC_ID_HEVC) {
uint8_t *data = st->codecpar->extradata;
int profile = FF_PROFILE_UNKNOWN;
int level = FF_LEVEL_UNKNOWN;
if (st->codecpar->profile != FF_PROFILE_UNKNOWN)
profile = st->codecpar->profile;
if (st->codecpar->level != FF_LEVEL_UNKNOWN)
level = st->codecpar->level;
/* check the boundary of data which from current position is small than extradata_size */
while (data && (data - st->codecpar->extradata + 19) < st->codecpar->extradata_size) {
/* get HEVC SPS NAL and seek to profile_tier_level */
if (!(data[0] | data[1] | data[2]) && data[3] == 1 && ((data[4] & 0x7E) == 0x42)) {
uint8_t *rbsp_buf;
int remain_size = 0;
int rbsp_size = 0;
/* skip start code + nalu header */
data += 6;
/* process by reference General NAL unit syntax */
remain_size = st->codecpar->extradata_size - (data - st->codecpar->extradata);
rbsp_buf = ff_nal_unit_extract_rbsp(data, remain_size, &rbsp_size, 0);
if (!rbsp_buf)
return;
if (rbsp_size < 13) {
av_freep(&rbsp_buf);
break;
}
/* skip sps_video_parameter_set_id u(4),
* sps_max_sub_layers_minus1 u(3),
* and sps_temporal_id_nesting_flag u(1) */
profile = rbsp_buf[1] & 0x1f;
/* skip 8 + 8 + 32 + 4 + 43 + 1 bit */
level = rbsp_buf[12];
av_freep(&rbsp_buf);
break;
}
data++;
}
if (st->codecpar->codec_tag == MKTAG('h','v','c','1') &&
profile != FF_PROFILE_UNKNOWN &&
level != FF_LEVEL_UNKNOWN) {
snprintf(attr, sizeof(attr), "%s.%d.4.L%d.B01", av_fourcc2str(st->codecpar->codec_tag), profile, level);
} else
goto fail;
}到这里在 FFmpeg 中解析 HEVC 的 extradata 数据就完成了，接下来看一下执行的效果：
./ffmpeg -i input.mp4 -c copy -bsf:v trace_headers -y -tag:v hvc1 -master_pl_name index.m3u8 output.m3u8说明一下：因为ffmpeg默认生成mp4的时候是Hev1的存储，所以这里需要手动设置一下tag为hvc1，因为苹果推荐这样。
然后查看一下生成的m3u8内容
#EXTM3U
#EXT-X-VERSION:3
#EXT-X-STREAM-INF:BANDWIDTH=6710,RESOLUTION=176x144,CODECS="hvc1.1.4.L60.B01"
output.m3u8完全符合预期，到这里，使用 FFmpeg 分析编码的数据信息的操作就完成了。
作者：大师兄悟空 公众号：流媒体技术
版权声明：本文内容转自互联网，本文观点仅代表作者本人。本站仅提供信息存储空间服务，所有权归原作者所有。如发现本站有涉嫌抄袭侵权/违法违规的内容， 请发送邮件至1393616908@qq.com 举报，一经查实，本站将立刻删除。
