ffmpeg-Filtering-and-streamcopy-cannot-be-used-together？

Yes, that's correct. In FFmpeg, filtering and stream copying (also known as "passthrough") are two different operations that cannot be used together on the same stream.

When you apply a filter to a video or audio stream, FFmpeg needs to decode the stream, apply the filter, and then re-encode the stream with the new filter settings. This process can be CPU-intensive and time-consuming, but it allows you to modify the content of the stream in various ways.

On the other hand, when you use the stream copy option (-c:v copy or -c:a copy) in FFmpeg, you are telling the program to simply copy the original stream without decoding or re-encoding it. This is much faster and less resource-intensive than filtering, but it only allows you to copy the stream as-is, without any modifications.

Therefore, if you want to apply a filter to a video or audio stream, you cannot use the stream copy option at the same time. You need to use a codec that supports filtering (such as libx264 for video or libmp3lame for audio) and apply the filter using the appropriate FFmpeg command.