[libavg-devel] Fwd: Audio Support Patch

[Nick Hebner]

---------- Forwarded message ----------
From: Nick Hebner <hebnern at gmail.com>
Date: Jan 30, 2008 12:40 PM
Subject: Re: [libavg-devel] Audio Support Patch
To: Ulrich von Zadow <uzadow at libavg.de>


Hey all,

After a few false starts and much hard work, I have finally gotten
asynchronous audio decoding working. My final approach is to mirror the
VideoDecoderThread with an AudioDecoderThread which lines up audio packets
which are consumed in the audio thread. Seeking is performed by one thread
or the other depending on what streams are being played back. In the
AsyncDemuxer, streams now have individual EOF flags so that all packets are
delivered.

My work has now been committed. With that, I believe that the core of the
audio subsystem is now complete. I will of course be addressing this
formally with test code in the coming days. On this, does anyone have a
suggestion on how I might go about synthesizing test files including audio?
I found a test tone wav file which sweeps a sine wave from 20Hz to 20KHz
which I thought could work for testing audio alone. I would like to test a
video with audio as well, but have not really found a way to combine them.
Any ideas?

On the subject of adding a node for audio-only files, I am again wondering
if a general 'media' node would be better than an 'audio' node. As I
remember the objection to a 'media' node was that layout parameters of such
a node (x, y, width, height, etc.) are nonsensical when the node is
audio-only. However, since the base Node class is the source of these
properties, an 'audio' node would have these properties anyway. So as I see
it, there are three options: 1. Create a media node which can play any media
file back, 2. Create seperate 'video' and 'audio' nodes both extending the
current Node, 3. Create seperate 'video' and 'audio' nodes, make Node less
layout oriented, and add a LayoutNode or something that encapsulates all
layout properties.

Let me know what you think.

Thanks,
Nick Hebner
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