Azure Media Services编码的mp4文件大小是原始的10倍 [英] Azure Media Services encoded mp4 file size is 10x the original

问题描述

我上传了一个15MB的mp4文件，并选择了通过HTML5播放选项进行编码。它创建了一个新的mp4文件，现在是158MB！这大小是10倍，为什么会这样呢？事实上，我选择的每个编码预设使得文件大小比原始的mp4文件的原始15MB大得多。我需要将视频传递给具有低带宽的PC客户端，因此将文件大小提高到这么大的程度是有效的。任何建议或洞察力是非常感激的。

I uploaded a 15MB mp4 file and chose the "Playback via HTML5" option for encoding. It created a new mp4 file that is now 158MB! This is 10x larger in size, why does this happen? In fact, every encoding preset that I choose makes the file size much larger than the original 15MB for the source mp4 file. I need to deliver the video to PC clients that have low bandwidth, so having the file size increase to this magnitude is counter productive. Any advice or insight is really appreciated.

推荐答案

您的原始输入文件几乎肯定以非常低的质量设置编码。 通过HTML5播放预设是一个非常高的质量水平，因为上一代HTML5流技术，您只能向用户呈现一个质量水平，所以Microsoft预设使这个质量水平相当不错（720p @ 4500 Kbps）

Your original input file was almost certainly encoded with very low quality settings. The "Playback via HTML5" preset is a very high quality level because with the previous-generation "HTML5 streaming" technology you can only present one quality level to users so the Microsoft presets make this a fairly good quality level (720p @ 4500 Kbps).

通常，为了通过互联网向第一世界的最终用户流式传输，我将使用具有以下质量等级的自适应流格式（例如DASH）：

Generally, for streaming over the internet to end-users in the 1st world, I would use an adaptive streaming format (e.g. DASH) with the following quality levels:

• 288p @ 400 Kbps


• 360p @ 900 Kbps


• 480p @ 1500 Kbps


• 720p @ 3000 Kbps


• 1080p @ 6000 Kbps

• 288p @ 400 Kbps
• 360p @ 900 Kbps
• 480p @ 1500 Kbps
• 720p @ 3000 Kbps
• 1080p @ 6000 Kbps

如果我们完全忽略音频并与您的15 MB输入文件进行比较，即使是最低的这些设置（非常恶劣的质量），只能编码只有5分钟的视频，最高质量等级编码只有20秒！

If we ignore audio entirely and compare against your 15 MB input file, even the lowest of these settings (at quite atrocious quality) would encode only 5 minutes of video with the highest quality level encoding only 20 seconds!

如果您希望提供最佳的最终用户体验，您应该使用自适应流技术，如DASH。这将使您能够为每个用户提供其网络连接最佳应对的质量水平。 dash.js 播放器能够在现代浏览器中播放这些视频。

If you wish to provide the best end-user experience, you should use an adaptive streaming technology such as DASH. This will enable you to serve each user with a quality level that their network connection can best cope with. The dash.js player is capable of playing such videos in modern browsers.

或者，您可以提供自定义预设将Azure Media Services编码为较低质量级别的视频。

Alternatively, you can provide custom presets to Azure Media Services to encode videos for a lower quality level.

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