961618 - [MediaEncoder] Reduce ISOMediaWriter memory usage

Status: RESOLVED FIXED

(Core :: Audio/Video: Recording, defect)

Description

[Alfredo Yang (:alfredo)]

The original design is to create a buffer (150k in this case) to write down the audio/video and ISO box info.
It can be improved by swapping the audio/video data pointer to an array of uint8_t array. So the ISOMediaWriter only need to allocate small memory for ISO boxes.

Comment 1

[Alfredo Yang (:alfredo)]

Attachment: reduce_muxer_memory_usage

Comment 2

[Chris Pearce [:cpearce (Not reading bugmail)]]

Comment on attachment 8362398 [details] [diff] [review]
reduce_muxer_memory_usage

Review of attachment 8362398 [details] [diff] [review]:
-----------------------------------------------------------------

r=cpearce with the const violation fixed.

::: content/media/encoder/fmp4_muxer/ISOMediaBoxes.cpp
@@ +87,5 @@
>        NS_ENSURE_SUCCESS(rv, rv);
>  
>        uint32_t len = frames.Length();
>        for (uint32_t i = 0; i < len; i++) {
> +        mControl->WriteAVData((nsTArray<uint8_t>&)frames.ElementAt(i)->GetFrameData());

You're casting a "const nsTArray" to a nsTArray here so you can change the contents. This is bad because some code may make assumptions based on GetFrameData() being const, and you break it here.

I think you should rename EncodedFrame::SetFrameData() to SwapFrameData(), and call:

nsTArray<uint8_t> frameData;
frames.ElementAt(i)->SwapFrameData(&frameData);
mControl->WriteAVData(frameData);

That way you don't violate the "contract" of that const is supposed to enforce.

Comment 3

[Randy Lin [:rlin] - Be Mozillian on 2015/01/26]

Put the renaming change reqeust of SetFrameData on Bug 959021  :)

Comment 4

[Alfredo Yang (:alfredo)]

Attachment: reduce_muxer_memory_usage

Using SwapOutFrameData(), carry r+.

https://tbpl.mozilla.org/?tree=Try&rev=295643509c0f

Comment 5

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/integration/b2g-inbound/rev/81d4d1ff6333

Comment 6

[Ryan VanderMeulen [:RyanVM]]

https://hg.mozilla.org/mozilla-central/rev/81d4d1ff6333