Twitter’s H.264 video requirements

I tried adding a video to a tweet. A video I encoded myself with ffmpeg.

It’s not like I know nothing about H.264 and ffmpeg, and I chose what I thought were sane and common parameters (mainly ffmpeg defaults), also sane aspect ratio and resolution etc.

Yet, no matter what I tried, I got the following error message when trying to send the tweet:

Your video file could not be processed. Please see tips for upload videos.

It linked to https://help.twitter.com/en/using-twitter/twitter-videos.

That is a rather unspecific help page. At the bottom it talks about constraints with respect to resolution, frame rate, aspect ratio — I got all that right.

I found other people’s ramblings about this error message:

But those resources were not really helping.

I then found https://developer.twitter.com/en/docs/twitter-api/v1/media/upload-media/uploading-media/media-best-practices which has a section “Video specifications and recommendations”. I double-checked things like pixel aspect ratio etc, and then I found two rather rather specific boundary conditions:

  • “Only YUV 4:2:0 pixel format is supported”
  • “H264 High Profile” (emphasis mine)

I was indeed using the “high” profile (see this for learning more about these profiles). However, the video file(s) I tried all used the yuv444p pixel format, as shown by this line of output of ffprobe:

Stream #0:0(und): Video: h264 (High 4:4:4 Predictive) (avc1 / 0x31637661), yuv444p, 1280x720 [SAR 1:1 DAR 16:9], 271 kb/s, 30 fps, 30 tbr, 15360 tbn, 60 tbc (default)

So, I followed this lovely resource and added the following command line flags to ffmpeg to explicitly set the profile High, level 4.0, and to set the pixel format to yuv420p:

-profile:v high
-level:v 4.0
-pix_fmt yuv420p

With these choices, ffprobe emitted

Video: h264 (High) (avc1 / 0x31637661), yuv420p

and Twitter accepted my H.264 video. Hope this helps!

By the way, the following resources help understanding the role of the pixel format and also the differences between yuv444 and yuv420: