mjpeg 和 h264 编解码器

发布于 2024-10-17 03:44:38 字数 26 浏览 3 评论 0原文

mjpeg 和 h264 有什么区别?

What is the difference between mjpeg and h264?

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飘逸的'云 2024-10-24 03:44:38

Mjpeg 只是单个文件或数据流中的 jpeg 文件列表。没有帧间压缩。换句话说,每一帧都是关键帧。

h264 与 Mjpeg 非常不同 - 从这里开始:http://en.wikipedia.org /wiki/H.264/MPEG-4_AVC

(Mpeg(无“j”)与 Mjpeg 不同,但与 H264 非常相似)

Mjpeg is just a list of jpeg files in a single file or data stream. There is no interframe compression. Put another way, every frame is a key frame.

h264 is very different from Mjpeg - start here: http://en.wikipedia.org/wiki/H.264/MPEG-4_AVC

(Mpeg (no 'j') is different from Mjpeg, but very similar to H264)

檐上三寸雪 2024-10-24 03:44:38

首先知道H.264& MPEG-4 AVC 和MPEG-4 第 10 部分是相同的。立即查看

  1. 对于移动摄像机或高活动区域的图像,MPEG4 和 H.264 提供相对于 MJPEG,节省的带宽很少。

  2. 正确的网络设计需要考虑最坏的情况,因此无论您是否使用 MJPEG、MPEG4 还是 H.264,您都需要专用相同数量的带宽。

  3. 由于没有帧内压缩,MJPEG 提供了更高的质量。

  4. 与 MJPEG 不同,MPEG-4 供应商偏离标准,增加了潜在的集成成本。

虽然 H.264 通常会显着降低带宽消耗,但它取决于多种因素(包括复杂性、流模式、帧速率和 i 帧速率)。 VBR 与 CBR 的选择尤其重要,对使用和性能影响特别大。最后,虽然 H.264 可以提供与 MJPEG 相同的可见图像质量,但根据您使用的设置(尤其是流模式),您很容易生成更差的质量。

first know that The H.264 & MPEG-4 AVC & MPEG-4 part 10 are the same. check this

now

  1. With moving cameras or images of high activity areas, MPEG4 and H.264 provide little bandwidth savings relative to MJPEG.

  2. Proper network design requires factoring in worse case scenarios so you will need to dedicate the same amount of bandwidth whether or not you use MJPEG, MPEG4 or H.264.

  3. MJPEG provides higher quality because of no intra-frame compression.

  4. Unlike MJPEG, with MPEG-4 vendors deviate from standards, increasing potential integration costs.

While H.264 generally reduces bandwidth consumption significantly, it depends on multiple factors (including complexity, streaming mode, frame rate and i frame rate). VBR vs CBR selection is especially important, having a especially large impact on use and performance. Finally, while H.264 can deliver the same visible image quality as MJPEG, depending on the settings you use (especially streaming mode), you can easily generate worse quality.

一瞬间的火花 2024-10-24 03:44:38

视频压缩通过两种形式的预测来实现:

  • 帧内预测:使用来自同一帧内的信息。
  • 帧间预测:使用来自参考帧的信息。

帧间预测通常要好得多,因为它允许以非常低的成本对帧之间相似的视频区域进行编码。这是 H.264 获得大部分压缩效果的地方。

单个 JPEG 图像只是一个帧内帧,而 MJPEG 只是 JPEG 图像的序列。 MJPEG 根本没有帧间。

事实上,即使是 H.264 帧内帧也能提供比 JPEG 帧更好的压缩(这就是 Google 推动 WebP 的部分原因)。

对于大多数用例,H.264 的压缩比 MJPEG 好得多,但编码/解码过程要复杂得多,这就是为什么没有太多计算能力的东西(例如网络摄像头)会输出 MJPEG。

对于一个好的 H.264 编码器来说,如果它的性能与一个好的 MJPEG 编码器一样差(例如随机生成的像素值),那一定是一种相当病态的情况。

Video compression is achieved from 2 forms of prediction:

  • Intra prediction: using information from within the same frame.
  • Inter prediction: using information from a reference frame.

Inter prediction is generally a lot better, as it allows areas of the video that are similar between frames to be encoded very cheaply. This is where H.264 gains most of its compression.

A single JPEG image is just an intra frame, and MJPEG is just a sequence of JPEG images. MJPEG has no inter frames at all.

In fact even an H.264 intra frame will offer much better compression than a JPEG frame (this is partly why Google pushed WebP).

For most use cases H.264 will have much better compression than MJPEG, but the encode/decode process is a lot more complex, which is why things without much computing power e.g. webcams spit out MJPEG.

It would have to be a rather pathological case for an good H.264 encoder to perform as badly as a good MJPEG encoder, e.g. randomly generated pixel values.

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