概覽
處理
通過設置在Zencoder作業上啟用CAE generate_dynamic_profiledynamic_profile_rendition值到作業的輸出。另外，您可以添加dynamic_profile_options，但這不是必需的。下載並檢查作業的輸入源文件後，Zencoder在源文件上運行CAE動態配置文件生成器。生成的動態輪廓梯形圖設置在編碼之前已添加到每個相應的輸出。對於具有dynamic_profile_rendition值的輸出，將自動設置以下設置：
widthheightframe_ratevideo_codecvideo_codec_profilevideo_codec_tiervideo_codec_levelvideo_reference_framesvideo_bframesvideo_bitratedecoder_bitrate_capdecoder_buffer_sizekeyframe_ratefixed_keyframe_interval
混合編解碼器輸出：您可以輸出混合的HEVC / H.264再現。看到CAE設置有關詳細信息。
其他輸出沒有dynamic_profile_rendition將在動態配置文件生成器運行時同時檢查輸入源後立即開始編碼。
配置準則dynamic_profile_options
渲染數量
創建的最小和最大演繹次數由min_renditions和max_renditions設置。為了獲得最佳性能，建議在這些限制之間留出一定的差距（例如，min_renditions到2和max_renditions到10），允許CAE配置文件生成器選擇最適合每個內容的編號。為了易於編碼內容，它可以產生更少的演繹，而對於更複雜的內容，它可以產生更多。還建議將min_renditions設置得盡可能小，以在不需要更多再現時節省帶寬。
決議案
默認情況下，CAE使用大約30種標準分辨率的階梯，範圍從192x108至7680x4320。可以通過以下方式將其限制在低端或高端最小分辨率和max_resolution設置。或者，可以在屏幕上提供分辨率和相關編解碼器設置的自定義列表。video_configurations設置。
GOP長度
的keyframe_rate設置控制最大值GOP編碼內容的長度。將此設置為與segment_seconds用於HLS / DASH編碼。否則，建議值為0.5，相當於2秒GOP長度。
比特率覆蓋
可以使用的比特率限制可以通過min_bitrate和max_bitrate設置。這將指示CAE至少分配min_bitrate第一次重演的Kbps，並將最後一次重演限制為最大max_bitrate Kbps。
為確保演繹比特率間隔適當，請使用min_granularity和max_granularity設置。例如，這些可用於確保從一個比特率到下一個比特率的步幅不小於50％的比特率增加或大於100％的比特率增加。請注意，大多數流創作指南均建議粒度不超過100％。
啟動延遲，惡劣網絡條件下的可靠性
為確保比特率階梯始終以足夠低的比特率開始，請使用max_first_rendition_bitrate設置。設置的第一個再現比特率越低，由於連接速度低，視頻播放器需要緩衝的可能性就越小。此外，如果流式清單表明首先加載最低比特率，則這也將直接影響啟動延遲。
支持舊設備
支持僅能Baselineselect_baseline_profile_configuration設置。設定此項後，至少一個演繹將被編碼為Baseline個人資料。附加約束（編解碼器配置文件，級別，參考幀數，b幀等）可以通過自定義進行控制video_configurations設置。
注意select_baseline_profile_configuration是true默認情況下，它要求至少一次演繹具有512x288或以下的分辨率。
VBR可變性控制
最大峰值比特率可以通過bitrate_cap_to_bitrate_ratio和bitrate_cap_offset設置。如果是比特率“R選擇“”進行演繹，然後coder_bitrate_cap計算為：
decoder_bitrate_cap = R * bitrate_cap_to_bitrate_ratio + bitrate_cap_offset
同樣，解碼器緩衝區限制可以通過buffer_size_to_bitrate_ratio和buffer_size_offset設置。的decoder_buffer_size計算為：
decoder_buffer_size = R * buffer_size_to_bitrate_ratio + buffer_size_offset
請注意，峰值比特率和緩衝區限制也可能受編解碼器配置文件和/或級別設置的約束。一些一般的設備兼容性問題可以通過限制來避免bitrate_cap_to_bitrate_ratio到2.0或更低，以及buffer_size_to_bitrate_ratio至2.0 * GOP length（馬上）。
CAE和分段輸出
CAE與Zencoder中的分段輸出兼容。在Output再現設置，設置type如segmented和適當的segment_seconds值。也，keyframe_rate和fixed_keyframe_interval設置必須在dynamic_profile_options。
CAE-HLS示例
{
"input": "s3://test_bucket/test_media.mp4",
"generate_dynamic_profile": true,
"dynamic_profile_options": {
"max_renditions": 6,
"min_renditions": 2,
"select_baseline_profile_configuration": true,
"keyframe_rate": "0.5",
"fixed_keyframe_interval": "true"
},
"outputs": [
{
"label": "CAE1",
"dynamic_profile_rendition": 1,
"base_url": "s3://test_bucket/outputs/HLS_CAE/CAE1",
"filename": "CAE1.m3u8",
"type": "segmented",
"segment_seconds": 2,
"byte_range_segmenting": true,
"generate_keyframe_manifest": "true",
"hls_protocol_version": 7,
"skip_audio": true
},
{
"label": "CAE2",
"dynamic_profile_rendition": 2,
"base_url": "s3://test_bucket/outputs/HLS_CAE/CAE2",
"filename": "CAE2.m3u8",
"type": "segmented",
"segment_seconds": 2,
"byte_range_segmenting": true,
"generate_keyframe_manifest": "true",
"hls_protocol_version": 7,
"skip_audio": true
},
{
"label": "CAE3",
"dynamic_profile_rendition": 3,
"base_url": "s3://test_bucket/outputs/HLS_CAE/CAE3",
"filename": "CAE3.m3u8",
"type": "segmented",
"segment_seconds": 2,
"byte_range_segmenting": true,
"generate_keyframe_manifest": "true",
"hls_protocol_version": 7,
"skip_audio": true
},
{
"label": "CAE4",
"dynamic_profile_rendition": 4,
"base_url": "s3://test_bucket/outputs/HLS_CAE/CAE4",
"filename": "CAE4.m3u8",
"type": "segmented",
"segment_seconds": 2,
"byte_range_segmenting": true,
"generate_keyframe_manifest": "true",
"hls_protocol_version": 7,
"skip_audio": true
},
{
"label": "CAE5",
"dynamic_profile_rendition": 5,
"base_url": "s3://test_bucket/outputs/HLS_CAE/CAE5",
"filename": "CAE5.m3u8",
"type": "segmented",
"segment_seconds": 2,
"byte_range_segmenting": true,
"generate_keyframe_manifest": "true",
"hls_protocol_version": 7,
"skip_audio": true
},
{
"label": "CAE6",
"dynamic_profile_rendition": 6,
"base_url": "s3://test_bucket/outputs/HLS_CAE/CAE6",
"filename": "CAE6.m3u8",
"type": "segmented",
"segment_seconds": 2,
"byte_range_segmenting": true,
"generate_keyframe_manifest": "true",
"hls_protocol_version": 7,
"skip_audio": true
}
{
"label": "Audio",
"audio_bitrate": "128",
"type": "segmented",
"segment_seconds": 2,
"byte_range_segmenting": true,
"skip_video": true,
"base_url": "s3://test_bucket/outputs/HLS_CAE/Audio/128k/",
"filename": "audio_128k.ac3"
},
{
"base_url": "s3://test_bucket/outputs/HLS_CAE/",
"filename": "master_playlist.m3u8",
"hls_protocol_version": 7,
"type": "playlist",
"allow_skipped_sources": true,
"alternate_audio": {
"128k_audio": {
"path": "Audio/128k/audio_128k.m3u8",
"language": "en",
"source": "Audio"
}
}
],
"streams": [
{
"path": "CAE1/CAE1.m3u8",
"source": "CAE1",
"audio": "128k_audio"
},
{
"path": "CAE2/CAE2.m3u8",
"source": "CAE2",
"audio": "128k_audio"
},
{
"path": "CAE3/CAE3.m3u8",
"source": "CAE3",
"audio": "128k_audio"
},
{
"path": "CAE4/CAE4.m3u8",
"source": "CAE4",
"audio": "128k_audio"
},
{
"path": "CAE5/CAE5.m3u8",
"source": "CAE5",
"audio": "128k_audio"
},
{
"path": "CAE6/CAE6.m3u8",
"source": "CAE6",
"audio": "128k_audio"
}
]
}
]
}
CAE-DASH示例
{
"input": "s3://test_bucket/test.mov",
"generate_dynamic_profile": true,
"dynamic_profile_options": {
"max_renditions": 6,
"min_renditions": 2,
"select_baseline_profile_configuration": true,
"keyframe_rate": "0.5",
"fixed_keyframe_interval": "true"
},
"outputs": [
{
"label": "CAE1",
"dynamic_profile_rendition": 1,
"base_url": "s3://test_bucket/outputs/DASH_CAE/CAE1",
"filename": "CAE1.mpd",
"type": "segmented",
"segment_seconds": 10,
"streaming_delivery_format": "dash",
"skip_audio": true,
"public": true
},
{
"label": "CAE2",
"dynamic_profile_rendition": 2,
"base_url": "s3://test_bucket/outputs/DASH_CAE/CAE2",
"filename": "CAE2.mpd",
"type": "segmented",
"segment_seconds": 10,
"streaming_delivery_format": "dash",
"skip_audio": true,
"public": true
},
{
"label": "CAE3",
"dynamic_profile_rendition": 3,
"base_url": "s3://test_bucket/outputs/DASH_CAE/CAE3",
"filename": "CAE3.mpd",
"type": "segmented",
"segment_seconds": 10,
"streaming_delivery_format": "dash",
"skip_audio": true,
"public": true
},
{
"label": "CAE4",
"dynamic_profile_rendition": 4,
"base_url": "s3://test_bucket/outputs/DASH_CAE/CAE4",
"filename": "CAE4.mpd",
"type": "segmented",
"segment_seconds": 10,
"streaming_delivery_format": "dash",
"skip_audio": true,
"public": true
},
{
"label": "CAE5",
"dynamic_profile_rendition": 5,
"base_url": "s3://test_bucket/outputs/DASH_CAE/CAE5",
"filename": "CAE5.mpd",
"type": "segmented",
"segment_seconds": 10,
"streaming_delivery_format": "dash",
"skip_audio": true,
"public": true
},
{
"label": "CAE6",
"dynamic_profile_rendition": 6,
"base_url": "s3://test_bucket/outputs/DASH_CAE/CAE6",
"filename": "CAE6.mpd",
"type": "segmented",
"segment_seconds": 10,
"streaming_delivery_format": "dash",
"skip_audio": true,
"public": true
},
{
"label": "Audio",
"audio_bitrate": "128",
"type": "segmented",
"segment_seconds": 10,
"streaming_delivery_format": "dash",
"skip_video": true,
"base_url": "s3://test_bucket/outputs/DASH_CAE/Audio/128k/",
"filename": "audio_128k.mpd",
"public": true
},
{
"base_url": "s3://test_bucket/outputs/DASH_CAE/",
"filename": "master_playlist.mpd",
"streaming_delivery_format": "dash",
"type": "playlist",
"allow_skipped_sources": true,
"public": true,
"streams": [
{
"path": "CAE1/CAE1.mpd",
"source": "CAE1"
},
{
"path": "CAE2/CAE2.mpd",
"source": "CAE2"
},
{
"path": "CAE3/CAE3.mpd",
"source": "CAE3"
},
{
"path": "CAE4/CAE4.mpd",
"source": "CAE4"
},
{
"path": "CAE5/CAE5.mpd",
"source": "CAE5"
},
{
"path": "CAE6/CAE6.mpd",
"source": "CAE6"
},
{
"path": "Audio/128k/audio_128k.mpd",
"source": "Audio"
}
]
}
]
}