如何设置VTCompressionSession的MaxH264SliceBytes属性 [英] How to set MaxH264SliceBytes property of VTCompressionSession

问题描述

iOS VTCompressionSession的属性为kVTCompressionPropertyKey_MaxH264SliceBytes.但是，我无法设置VTCompressionSession的kVTCompressionPropertyKey_MaxH264SliceBytes属性.它会返回-12900错误代码(kVTPropertyNotSupportedErr)，并且VTCompressionProperties.h文件中的描述为如果受H.264编码器支持，则该值将尽可能限制编码器生成的切片的字节大小."

iOS VTCompressionSession has a property which is kVTCompressionPropertyKey_MaxH264SliceBytes. However, I cannot set the kVTCompressionPropertyKey_MaxH264SliceBytes property of VTCompressionSession. It returns a -12900 error code (kVTPropertyNotSupportedErr) and the description in VTCompressionProperties.h file says "If supported by an H.264 encoder, the value limits the size in bytes of slices produced by the encoder, where possible."

因此，我了解到某些编码器设置支持使用此属性.有人知道这些设置是什么吗?

So I understand that usage of this property is supported for some encoder settings. Does anybody know what that settings are?

谢谢.

推荐答案

Apple开发者技术支持回答了我们: 如果VTSessionCopySupportedPropertyDictionary返回的字典包含kVTCompressionPropertyKey_MaxH264SliceBytes键，则VTCompressionSession仅支持配置最大切片大小.

As Apple Developer Technical Support answered us: The VTCompressionSession only supports configuring the maximum slice size if the dictionary returned by VTSessionCopySupportedPropertyDictionary contains the kVTCompressionPropertyKey_MaxH264SliceBytes key.

事实证明，在我测试过的任何设备(iPhone 5、6s)上，iOS 8.4都不支持它->可能没有实现，至少在iOS上没有实现.

Turns out that it is not supported by iOS 8.4 on any of the devices I've tested (iPhone 5, 6s) -> it's probably not implemented, at least not on iOS.

技术支持建议我们使用 Apple Bug Reporter 提出增强请求.我提交了一份，建议您也提交一份，因为苹果公司根据提交的重复件数报告了优先级错误报告.

The technical support suggested we file an enhancement request using the Apple Bug Reporter. I filed one, and I suggest you file one as well, as Apple priorities bug reports based on the number of duplicates filed.

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