[Android/IOS] stream copy very slow

[tanersener]

Copying an input file is expected to complete fast since it does no contain any encoding/decoding.

Unfortunately this is not the case in IOS v3.0 release. -i input_path -c copy output_path command completes in 34 seconds by default. If redirection is disabled then copying completes in 1.5 seconds. This means that enabling log/statistics redirection slows down the copying operation. Reason of this case should be analyzed.

Additional testing confirms that only copy mode (-c copy) is affected from this issue. The speed of other operations is not effected by enabling/disabling redirection.

[tanersener]

On Android the same copy command completes in 4.3 seconds by default. If redirection is disabled duration decreases to 1.2 seconds. This decrease should be analyzed too.

[tanersener]

Analysis shows that log level validation for log callbacks is performed too late. This causes too many (unwanted) low severity log messages to be processed, which decreases the whole processing speed. Log level validation should be performed as early as possible not to have a performance decrease.

ps: Both platforms suffer from this issue.