Which transcoding cloud providers provide the best video quality?

When it comes to cloud transcoding, all services (including Amazon AWS Elemental MediaConvert, Google Cloud Video Intelligence API, Microsoft Azure Media Services, Zencoder, encoding.com) promote FAST and Good quality transcoding. What they don't say is that you cannot get both at once, as fast transcoding will inherently result in a lower quality, and high quality will result in longer transcoding times. As they all give some of their servers CPU or GPU time, there's a bigger chance they mostly focus on time-to-encode.

All of them use ffmpeg x264 but which one of them provide some objective video quality results ?

How to get metrics about the video quality of x264 output produced by ffmpeg?

To get metrics about the video quality of x264 output produced by ffmpeg, you can use video quality analysis tools such as VMAF, PSNR, and SSIM. These tools can help you measure the video quality by comparing the original video with the compressed output video.

Here are the general steps you can follow to get video quality metrics using VMAF:

1. Install VMAF: You can download and install VMAF from the Netflix VMAF GitHub repository.
2. Prepare the input video and the output video: You should have the original input video and the compressed output video (produced by ffmpeg x264) ready for analysis.
3. Run VMAF: Use the following command to run VMAF and generate the video quality metrics:

./vmafossexec yuv420p <input_video_file> <output_video_file> model_path=<vmaf_model_file_path>

This command will generate a score file containing the VMAF score, PSNR, and SSIM values. The score file will also include the number of I, B, and P frames in the output video, as well as the QP values used during encoding.

By analyzing the score file, you can get an idea of the video quality and how it is affected by the encoding parameters such as QP and the number of I, B, and P frames. You can then adjust the encoding parameters to optimize the video quality for your specific use case.

Which cloud transcoding providers display VMAF score for their output?

Several cloud transcoding providers display VMAF scores for their output. Here are some of them:

iReplay.TV: as the service focuses on video quality and transparency, a VMAF score is provided for any offline transcoding.

AWS Elemental MediaConvert: AWS Elemental MediaConvert displays VMAF scores in its job completion report. You can use these scores to evaluate the quality of your transcoded videos and fine-tune your encoding settings.

Google Cloud Video Intelligence API: Google Cloud Video Intelligence API provides VMAF scores as part of its video analysis services. You can use these scores to evaluate the quality of your videos and optimize your encoding settings.

Encoding.com: Encoding.com provides VMAF scores as part of its quality control services. You can use these scores to evaluate the quality of your videos and make adjustments to your encoding settings.

Bitmovin: Bitmovin provides VMAF scores as part of its analytics services. You can use these scores to evaluate the quality of your videos and optimize your encoding settings.

Not all cloud transcoding providers display VMAF scores or other quality metrics for their output. Therefore, it's recommended to check the documentation and features of each provider to determine which one offers the most suitable video quality analysis tools for your specific needs.

If no VMAF score can be provided, there is a good chance that video quality is simply a marketing bullet point. If getting a VMAF score comes optional for an additional cost over transcoding, expect your cloud provider to focus on (its) margin more than video quality for customers.

Article written by
Sylvain Corvaisier

Independent streaming and iOS engineer

Last modified: January 8th, 2025