LowmemKiller：Excessive native memory usage leads to system low memory conditions.

[yinyongliang94]

Configuring ASS subtitles causes the system's native memory usage to keep increasing the longer playback continues, eventually triggering the low memory killer.I suspect that Bitmaps are being allocated on the native side, but their memory is not being released.

code：AssKt.c -> nativeAssRenderFrame()

[moi15moi]

Have you used the main branch?
A fix has been landed on the main branch a week ago.

[yinyongliang94]

a week ago？Has it been released yet，v0.3.0-beta02?

[peerless2012]

There is a new v0.3.0-rc01 include the leak fix, free to have a try.

[yinyongliang94]

tks

[yinyongliang94]

v0.3.0-rc01 had no effect; the native memory usage is still too high, causing low memory issues. Could it be related to the ass_render_frame function?

[yinyongliang94]

When testing with this demo, after adding ASS subtitles, the app’s native memory usage keeps increasing over time during playback, eventually leading to memory issues

[peerless2012]

The native memory usage increase, because libass will cache the font render result.

But the memory usage increase during playback for ever, it's a problem we are looking for.

[yinyongliang94]

yeah, I tested by keeping only the ass_render_frame() line in the AssKt#nativeAssRenderFrame function, and the memory issue still occurs

[peerless2012]

Maybe the event add from kotlin, not release in jni.

[yinyongliang94]

It's not a Kotlin issue. The third parameter bitmap_max_size in ass_set_cache_limits is in megabytes (MB). You mistakenly passed a value in bytes to an interface that expects megabytes, causing the ASS library to assume an extremely large cache limit. As a result, ass_render_frame() continuously caches bitmaps without releasing them, leading to unbounded native memory growth and eventually triggering a native OOM (Out of Memory) error.

[yinyongliang94]

I simply modified render.setCacheLimit(1024, (totalMemoryBytes / 8).toInt()) to render.setCacheLimit(1024, (totalMemoryBytes / (1024 * 1024) / 8).toInt()) in the AssHandler#createRenderIfNeeded method, and the app's native memory usage no longer grows excessively.

[peerless2012]

I think you find the solution...

/**
 * \brief Set hard cache limits.  Do not set, or set to zero, for reasonable
 * defaults.
 *
 * \param priv renderer handle
 * \param glyph_max maximum number of cached glyphs
 * \param bitmap_max_size maximum bitmap cache size (in MB)
 */
void ass_set_cache_limits(ASS_Renderer *priv, int glyph_max,
                          int bitmap_max_size);

ass_set_cache_limits

The bitmap_max_size should be MB, current is byte. LOL