Since there is no more specific information, it is difficult to locate the problem. One possible reason is that the video playback library you use only supports real devices and does not support simulators. Because the CPU architecture corresponding to the real machine is armv7/armv7s/arm64, etc., and the CPU architecture corresponding to the simulator is i386/x86_64, etc.
As SamirChen said, try using the soft solution. Soft decoding has better errors and effects in most cases, as well as some smoothness, but it consumes a lot of power
Since there is no more specific information, it is difficult to locate the problem. One possible reason is that the video playback library you use only supports real devices and does not support simulators. Because the CPU architecture corresponding to the real machine is armv7/armv7s/arm64, etc., and the CPU architecture corresponding to the simulator is i386/x86_64, etc.
As SamirChen said, try using the soft solution. Soft decoding has better errors and effects in most cases, as well as some smoothness, but it consumes a lot of power