The reason some people don't get video streaming to work is that they don't pay attention when they read threads or watch videos. Some tiny steps are vital and if they are just skipped then it all goes to pot.
I asked about audio because I took receipt of a very nice H264 from the Far East a few days ago and it struggles with Blynk because of the audio stream rather than the more complex video stream. Audio is not important within our project and I suspect the same applies for other Blynkers who merely want to have "live" moving pictures of some event rather than video with sound.
In the last hour I have managed to get the H264 camera to stream to Blynk on a very cheap Android Alcatel onetouch smartphone. The phone is running Android 4.4.2 and the cost new was around $35.
I have 2 Samsung Android devices that cost perhaps $300 to $500 when new and they run similar Android versions but currently they will not accept the stream in Blynk. One Samsung has Android 4.4.4 and the other has 4.2.2 so as you will see they are quite old and the Android versions are either side of the Alcatel phone that does work.
Now getting the Alcatel to accept the stream in Blynk didn't happen by chance and I have spent many man days working with video since the widget was introduced a few months ago. This has involved working with $3 USB webcams (no good for Blynk without adding extra hardware), Android cameras and the H264 camera.
I suspect one of the Samsung's is simply running out of memory when it tries to play the video stream in Blynk as the phone is crammed full of applications, many of which insist on running in the background despite serious efforts to stop them. In the coming days I will check with a friend who has the same phone, but less background apps, to see if it works for them.
@scientist1995 what are the make and model of your cameras?