I can hear audio but no video from mp4

Question

I have two mp4 videos. I want to stream the video to a UDP multicast address. One of the video streams (video and audio) but the other only streams audio. Both videos are h264 encoded.

I checked the moov atom on both videos and they exist at the start of the file so it is not that the moov atom is at the end of the file.

Any ideas why one of the videos does not show any video (only hear the audio)?

One thing I noticed is we are using an old version of VLC but when we move to a newer version both videos stream video and audio. In order convince our customers to move to newer versions of VLC I first need to know what has caused the issue.

Answer 1

H.264 has multiple profiles ... baseline, main, and high to name a few of the more common ones ... along with multiple levels. If a video stream can't be played in an older version of VLC, one possibility is that it's using a high profile and level which might not have been supported in the old version of VLC you're dealing with.

You can use ffprobe to help determine this info for a given stream:

ffprobe -loglevel error -show_streams [videofile]