Tiny4412 Android5.0 定制media codecs相关的格式

tiny4412 4412 Android 5.0系统上，支持以下的media格式，文件位于: device/friendly-arm/tiny4412/media_codecs.xml

打开后我们可以看到这个xml包含相关的音视频编解码支持的格式:

<?xml version="1.0" encoding="utf-8" ?>
<!-- Copyright (C) 2012 The Android Open Source Project

     Licensed under the Apache License, Version 2.0 (the "License");
     you may not use this file except in compliance with the License.
     You may obtain a copy of the License at

          http://www.apache.org/licenses/LICENSE-2.0

     Unless required by applicable law or agreed to in writing, software
     distributed under the License is distributed on an "AS IS" BASIS,
     WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     See the License for the specific language governing permissions and
     limitations under the License.
-->

<!--
<!DOCTYPE MediaCodecs [
<!ELEMENT MediaCodecs (Decoders,Encoders)>
<!ELEMENT Decoders (MediaCodec*)>
<!ELEMENT Encoders (MediaCodec*)>
<!ELEMENT MediaCodec (Type*,Quirk*)>
<!ATTLIST MediaCodec name CDATA #REQUIRED>
<!ATTLIST MediaCodec type CDATA>
<!ELEMENT Type EMPTY>
<!ATTLIST Type name CDATA #REQUIRED>
<!ELEMENT Quirk EMPTY>
<!ATTLIST Quirk name CDATA #REQUIRED>
]>

There's a simple and a complex syntax to declare the availability of a
media codec:

A codec that properly follows the OpenMax spec and therefore doesn't have any
quirks and that only supports a single content type can be declared like so:

    <MediaCodec name="OMX.foo.bar" type="something/interesting" />

If a codec has quirks OR supports multiple content types, the following syntax
can be used:

    <MediaCodec name="OMX.foo.bar" >
        <Type name="something/interesting" />
        <Type name="something/else" />
        ...
        <Quirk name="requires-allocate-on-input-ports" />
        <Quirk name="requires-allocate-on-output-ports" />
        <Quirk name="output-buffers-are-unreadable" />
    </MediaCodec>

Only the three quirks included above are recognized at this point:

"requires-allocate-on-input-ports"
    must be advertised if the component does not properly support specification
    of input buffers using the OMX_UseBuffer(...) API but instead requires
    OMX_AllocateBuffer to be used.

"requires-allocate-on-output-ports"
    must be advertised if the component does not properly support specification
    of output buffers using the OMX_UseBuffer(...) API but instead requires
    OMX_AllocateBuffer to be used.

"output-buffers-are-unreadable"
    must be advertised if the emitted output buffers of a decoder component
    are not readable, i.e. use a custom format even though abusing one of
    the official OMX colorspace constants.
    Clients of such decoders will not be able to access the decoded data,
    naturally making the component much less useful. The only use for
    a component with this quirk is to render the output to the screen.
    Audio decoders MUST NOT advertise this quirk.
    Video decoders that advertise this quirk must be accompanied by a
    corresponding color space converter for thumbnail extraction,
    matching surfaceflinger support that can render the custom format to
    a texture and possibly other code, so just DON'T USE THIS QUIRK.

-->

<MediaCodecs>
    <Decoders>
        <MediaCodec name="OMX.SEC.MPEG4.Decoder" type="video/mp4v-es" />
        <MediaCodec name="OMX.SEC.H263.Decoder" type="video/3gpp" />
        <MediaCodec name="OMX.SEC.AVC.Decoder" type="video/avc" />
        <MediaCodec name="OMX.SEC.FP.AVC.Decoder" type="video/avc" />
        <MediaCodec name="OMX.SEC.MPEG2.Decoder" type="video/mpeg2" />
        <MediaCodec name="OMX.SEC.WMV.Decoder" type="video/vc1" />
        <MediaCodec name="OMX.SEC.MP3.Decoder" >
          <Type name="audio/mpeg" />
          <Quirk name="supports-multiple-frames-per-inputbuffer" />
          <Quirk name="needs-flush-before-disable" />
	    </MediaCodec>

        <MediaCodec name="OMX.google.mp3.decoder" type="audio/mpeg" />
        <MediaCodec name="OMX.google.amrnb.decoder" type="audio/3gpp" />
        <MediaCodec name="OMX.google.amrwb.decoder" type="audio/amr-wb" />
        <MediaCodec name="OMX.google.aac.decoder" type="audio/mp4a-latm" />
        <MediaCodec name="OMX.google.g711.alaw.decoder" type="audio/g711-alaw" />
        <MediaCodec name="OMX.google.g711.mlaw.decoder" type="audio/g711-mlaw" />
        <MediaCodec name="OMX.google.vorbis.decoder" type="audio/vorbis" />

        <MediaCodec name="OMX.google.mpeg4.decoder" type="video/mp4v-es" />
        <MediaCodec name="OMX.google.h263.decoder" type="video/3gpp" />
        <MediaCodec name="OMX.google.h264.decoder" type="video/avc" />
        <MediaCodec name="OMX.google.vpx.decoder" type="video/x-vnd.on2.vp8" />
        <MediaCodec name="FfmpegVideoDecoder" type="video/ffmpeg" />
        <MediaCodec name="FfmpegAudioDecoder" type="audio/ffmpeg" />
    </Decoders>

    <Encoders>
        <MediaCodec name="OMX.SEC.MPEG4.Encoder" type="video/mp4v-es" />
        <MediaCodec name="OMX.SEC.H263.Encoder" type="video/3gpp" />
        <MediaCodec name="OMX.SEC.AVC.Encoder" type="video/avc" />

        <MediaCodec name="OMX.google.amrnb.encoder" type="audio/3gpp" />
        <MediaCodec name="OMX.google.amrwb.encoder" type="audio/amr-wb" />
        <MediaCodec name="OMX.google.aac.encoder" type="audio/mp4a-latm" />
        <MediaCodec name="OMX.google.flac.encoder" type="audio/flac" />
    </Encoders>
</MediaCodecs>

这里面，一部分是Android系统在发布的时候就自带支持的一些格式，而有一些格式是厂商加进去的，如果正式发布产品，有些格式还不是完全免费的，需要支付一定的认证费用才能使用对应的格式，那么再产品定制环节，我们可以根据需求来删除对应的格式，同时也可以添加对应的格式。
至于这部分，后面找到对应的java文件会再做分析：

(未完待补充!)