我应该对.mp4文件使用MP3或AAC编解码器吗? [英] Should I use the MP3 or AAC codec for a .mp4 file?

问题描述

在Mac OS X上，我们已经使用 ffmpeg 进行了编码.该过程将获取源视频以及其中的几个文件:.m3u8视频，.mp4视频和.mp3音频文件

We have an encoding process in place using ffmpeg on Mac OS X. This process will take a source video and a couple files from that: .m3u8 video, .mp4 video and .mp3 audio file.

默认情况下，我们使用了m3u8流程中的视频，该视频是带有AAC(通过 libfaac )音频的h264(通过 libx264 )视频.

By default we've used the video from our m3u8 process which is a h264 (via libx264) video with AAC (via libfaac) audio.

我们主要在移动设备上使用这些视频(因此m3u8文件)，但我们也将.mp4文件用于Android，Windows Phone等.越来越多的我们还需要通过以下两种方式在网络上提供这些视频: Flash播放器或HTML5播放器.

We are mostly using these videos on mobile devices (hence the m3u8 files) but we also use the .mp4 files for Android, Windows Phone, etc. More and more we also need to offer these same videos on the web via either a flash player or HTML5 player.

因此，我们希望为所有这些用途提供最佳的音频/视频编解码器组合……我感到困惑的是.mp4文件的标准"是什么?

Therefore, we'd like to have the best audio/video codec combo for all these uses ... where I'm confused is to what is "standard" for a .mp4 file?

如果.mp4使用mp3编解码器，则可以在除QuickTime之外的任何地方正常播放，在QuickTime中可以播放视频，但没有音频(在VLC播放器中可以正常播放)

If the .mp4 uses the mp3 codec then it plays just fine everywhere but QuickTime, in QuickTime the video plays but there is not audio (works just fine in VLC player tho.)

有人告诉我，这是由于QuickTime如何使用文件扩展名来假定有关视频的信息，而不是试图从文件中实际获取编解码器数据?如果我们对同一个文件进行编码，但对音频编解码器使用AAC，则确实有道理，那么在QuickTime中它就可以正常工作.

I've been told it's due to how QuickTime uses file extensions to assume information about the video instead of trying to actually get the codec data from the file? This does make some sense, if we encode the same file but use AAC for the audio codec then it works just fine in QuickTime.

所以---什么是正确的"或理想的"音频/视频编解码器组合---使用AAC最好且安全(即使它不是免费"编解码器?

So --- what's the "correct" or "ideal" audio/video codec combo --- is it best and safe to use AAC (i.e. will it work on a broad range of devices) even though it's not a "free" codec?

推荐答案

预留了兼容性问题，您可能需要考虑从mp3到aac的代码转换引起的质量损失.由于您的原始音频是mp3编码的，因此，通过重新混合mp3比特流而不是转码为aac(即使在给定的比特率下aac比mp3更好)，您将获得更好的最终结果.

Compatibility issues set aside, you might want to take into account the quality loss induced by transcoding from mp3 to aac. As your original audio is mp3 encoded, you will have a better end result by remuxing the mp3 bitstream instead of transcoding to aac (even if aac is better than mp3 at a given bitrate).

如果您的工作流程要求降低原始mp3的比特率，那么我的观点失去了相关性.

If your workflow requires lowering the bitrate of the original mp3, then my point looses relevance.

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