Android MediaCodec 简明教程（一）：使用 MediaCodecList 查询 Codec 信息，并创建 MediaCodec 编解码器

分类:热门推荐日期:2024-03-07浏览:1评论:0

系列文章目录

文章目录

  • 系列文章目录
  • 前言
  • 一、MediaCodecList 是什么？
  • 二、MediaCodecList 使用方法
    • 1. 获取 MediaCodecList 实例
    • 2. 列出设备上支持的编解码器
    • 3. 获取编解码器详细信息
    • 4. 判断设备是否支持某种编解码器
    • 5. 查询默认的编解码器
    • 三、通过 MediaCodecList 创建 MediaCodec
      • 3.1 创建解码器
      • 3.2 创建编码器
      • 总结
      • 参考

        前言

        最近在学习 Android MediaCodec 相关的知识，准备开个新坑把学习过程记录下来，总结成 MediaCodec 教程。在介绍 MediaCodec 编解码之前，让我们学习一些其他与之配套的组件，今天要讲的是 MediaCodecList。

        提示：以下是本篇文章正文内容，下面案例可供参考

        一、MediaCodecList 是什么？

        MediaCodecList 是 Android 提供的一个类，用于查询设备上可用的编解码器（codecs）。编解码器是用于编码和解码数据的软件组件，例如音频或视频数据。

        MediaCodecList 提供了一种方法来获取设备上所有可用的编解码器的信息，包括它们的名称、支持的数据格式等。这对于开发需要处理音频或视频数据的应用程序非常有用。

        例如，你可以使用 MediaCodecList 来查找设备上是否有支持特定视频格式的编解码器，如果有，你可以使用这个编解码器来处理这种格式的视频数据。

        二、MediaCodecList 使用方法

        1. 获取 MediaCodecList 实例

        可以通过以下方式获取 MediaCodecList 实例：

        MediaCodecList codecList = new MediaCodecList(MediaCodecList.ALL_CODECS);

        其中，ALL_CODECS 表示列出所有编解码器，也可以使用 REGULAR_CODECS 表示只列出正常编解码器。在笔者的华为测试机上，ALL_CODECS 与 REGULAR_CODECS 有部分差别，在 ALL_CODECS 中有一些带 .secure 的解码器类型 ，例如 OMX.hisi.video.decoder.avc.secure

        2. 列出设备上支持的编解码器

        可以通过以下方式列出设备上支持的编解码器：

        MediaCodecInfo[] codecInfos = codecList.getCodecInfos();

        其中，codecInfos 是一个包含所有支持的编解码器信息的数组。

        3. 获取编解码器详细信息

        可以通过以下方式获取编解码器的详细信息：

        MediaCodecInfo codecInfo = codecInfos[i];
String name = codecInfo.getName(); // 编解码器名称
String canonicalName = codecInfo.getCanonicalName(); // 编解码器规范名称
boolean isEncoder = codecInfo.isEncoder(); // 是编码器吗？
boolean isVendor = codecInfo.isVendor(); // 是厂商提供的吗？
boolean isSoftwareOnly = codecInfo.isSoftwareOnly(); // 纯软件实现的编解码器？
boolean isHardwareAccelerated = codecINfo.isHardwareAccelerated(); // 有硬件加速？
String[] types = codecInfo.getSupportedTypes(); // 支持的媒体类型
MediaCodecInfo.CodecCapabilities capabilities = codecInfo.getCapabilitiesForType(type); // 编解码器的配置参数

        canonicalName 是编码器规范名称，在 Android 中，一个编解码器可能有多个别名，为了保持向后兼容性，设备实现可能会为同一个编解码器提供多个别名。getCanonicalName() 方法返回的是编解码器的规范名称，它必须是唯一的，不能是别名。

        isHardwareAccelerated 查询是否有硬件加速，很多厂商提供编解码器都有硬件加速。

        下面是笔者机器上的编解码器信息：

        codec: c2.android.aac.decoder, canonicalName: c2.android.aac.decoder, types: [audio/mp4a-latm], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.aac.decoder, canonicalName: c2.android.aac.decoder, types: [audio/mp4a-latm], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.aac.encoder, canonicalName: c2.android.aac.encoder, types: [audio/mp4a-latm], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.aac.encoder, canonicalName: c2.android.aac.encoder, types: [audio/mp4a-latm], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.amrnb.decoder, canonicalName: c2.android.amrnb.decoder, types: [audio/3gpp], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.amrnb.decoder, canonicalName: c2.android.amrnb.decoder, types: [audio/3gpp], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.amrnb.encoder, canonicalName: c2.android.amrnb.encoder, types: [audio/3gpp], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.amrnb.encoder, canonicalName: c2.android.amrnb.encoder, types: [audio/3gpp], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.amrwb.decoder, canonicalName: c2.android.amrwb.decoder, types: [audio/amr-wb], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.amrwb.decoder, canonicalName: c2.android.amrwb.decoder, types: [audio/amr-wb], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.amrwb.encoder, canonicalName: c2.android.amrwb.encoder, types: [audio/amr-wb], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.amrwb.encoder, canonicalName: c2.android.amrwb.encoder, types: [audio/amr-wb], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.flac.decoder, canonicalName: c2.android.flac.decoder, types: [audio/flac], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.flac.decoder, canonicalName: c2.android.flac.decoder, types: [audio/flac], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.flac.encoder, canonicalName: c2.android.flac.encoder, types: [audio/flac], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.flac.encoder, canonicalName: c2.android.flac.encoder, types: [audio/flac], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.g711.alaw.decoder, canonicalName: c2.android.g711.alaw.decoder, types: [audio/g711-alaw], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.g711.alaw.decoder, canonicalName: c2.android.g711.alaw.decoder, types: [audio/g711-alaw], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.g711.mlaw.decoder, canonicalName: c2.android.g711.mlaw.decoder, types: [audio/g711-mlaw], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.g711.mlaw.decoder, canonicalName: c2.android.g711.mlaw.decoder, types: [audio/g711-mlaw], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.gsm.decoder, canonicalName: c2.android.gsm.decoder, types: [audio/gsm], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.gsm.decoder, canonicalName: c2.android.gsm.decoder, types: [audio/gsm], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.mp3.decoder, canonicalName: c2.android.mp3.decoder, types: [audio/mpeg], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.mp3.decoder, canonicalName: c2.android.mp3.decoder, types: [audio/mpeg], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.opus.decoder, canonicalName: c2.android.opus.decoder, types: [audio/opus], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.opus.decoder, canonicalName: c2.android.opus.decoder, types: [audio/opus], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.opus.encoder, canonicalName: c2.android.opus.encoder, types: [audio/opus], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.raw.decoder, canonicalName: c2.android.raw.decoder, types: [audio/raw], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.raw.decoder, canonicalName: c2.android.raw.decoder, types: [audio/raw], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.vorbis.decoder, canonicalName: c2.android.vorbis.decoder, types: [audio/vorbis], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.vorbis.decoder, canonicalName: c2.android.vorbis.decoder, types: [audio/vorbis], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.dolby.ac3.decoder, canonicalName: OMX.dolby.ac3.decoder, types: [audio/ac3], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.dolby.ac4.decoder, canonicalName: OMX.dolby.ac4.decoder, types: [audio/ac4], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.dolby.eac3.decoder, canonicalName: OMX.dolby.eac3.decoder, types: [audio/eac3], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.dolby.eac3_joc.decoder, canonicalName: OMX.dolby.eac3_joc.decoder, types: [audio/eac3-joc], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.avc, canonicalName: OMX.hisi.video.decoder.avc, types: [video/avc], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.avc.secure, canonicalName: OMX.hisi.video.decoder.avc.secure, types: [video/avc], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.hevc, canonicalName: OMX.hisi.video.decoder.hevc, types: [video/hevc], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.hevc.secure, canonicalName: OMX.hisi.video.decoder.hevc.secure, types: [video/hevc], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.mpeg2, canonicalName: OMX.hisi.video.decoder.mpeg2, types: [video/mpeg2], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.mpeg4, canonicalName: OMX.hisi.video.decoder.mpeg4, types: [video/mp4v-es], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.vp8, canonicalName: OMX.hisi.video.decoder.vp8, types: [video/x-vnd.on2.vp8], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.vp9, canonicalName: OMX.hisi.video.decoder.vp9, types: [video/x-vnd.on2.vp9], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.decoder.vp9.secure, canonicalName: OMX.hisi.video.decoder.vp9.secure, types: [video/x-vnd.on2.vp9], isEncoder = false, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.encoder.avc, canonicalName: OMX.hisi.video.encoder.avc, types: [video/avc], isEncoder = true, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: OMX.hisi.video.encoder.hevc, canonicalName: OMX.hisi.video.encoder.hevc, types: [video/hevc], isEncoder = true, isVendor = true, isAlias = false, isSoftwareOnly = false, isHardwareAccelerated = true
codec: c2.android.av1.decoder, canonicalName: c2.android.av1.decoder, types: [video/av01], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.avc.decoder, canonicalName: c2.android.avc.decoder, types: [video/avc], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.h264.decoder, canonicalName: c2.android.avc.decoder, types: [video/avc], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.avc.encoder, canonicalName: c2.android.avc.encoder, types: [video/avc], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.h264.encoder, canonicalName: c2.android.avc.encoder, types: [video/avc], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.h263.decoder, canonicalName: c2.android.h263.decoder, types: [video/3gpp], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.h263.decoder, canonicalName: c2.android.h263.decoder, types: [video/3gpp], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.h263.encoder, canonicalName: c2.android.h263.encoder, types: [video/3gpp], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.h263.encoder, canonicalName: c2.android.h263.encoder, types: [video/3gpp], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.hevc.decoder, canonicalName: c2.android.hevc.decoder, types: [video/hevc], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.hevc.decoder, canonicalName: c2.android.hevc.decoder, types: [video/hevc], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.hevc.encoder, canonicalName: c2.android.hevc.encoder, types: [video/hevc], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.mpeg4.decoder, canonicalName: c2.android.mpeg4.decoder, types: [video/mp4v-es], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.mpeg4.decoder, canonicalName: c2.android.mpeg4.decoder, types: [video/mp4v-es], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.mpeg4.encoder, canonicalName: c2.android.mpeg4.encoder, types: [video/mp4v-es], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.mpeg4.encoder, canonicalName: c2.android.mpeg4.encoder, types: [video/mp4v-es], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.vp8.decoder, canonicalName: c2.android.vp8.decoder, types: [video/x-vnd.on2.vp8], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.vp8.decoder, canonicalName: c2.android.vp8.decoder, types: [video/x-vnd.on2.vp8], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.vp8.encoder, canonicalName: c2.android.vp8.encoder, types: [video/x-vnd.on2.vp8], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.vp8.encoder, canonicalName: c2.android.vp8.encoder, types: [video/x-vnd.on2.vp8], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.vp9.decoder, canonicalName: c2.android.vp9.decoder, types: [video/x-vnd.on2.vp9], isEncoder = false, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.vp9.decoder, canonicalName: c2.android.vp9.decoder, types: [video/x-vnd.on2.vp9], isEncoder = false, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false
codec: c2.android.vp9.encoder, canonicalName: c2.android.vp9.encoder, types: [video/x-vnd.on2.vp9], isEncoder = true, isVendor = false, isAlias = false, isSoftwareOnly = true, isHardwareAccelerated = false
codec: OMX.google.vp9.encoder, canonicalName: c2.android.vp9.encoder, types: [video/x-vnd.on2.vp9], isEncoder = true, isVendor = false, isAlias = true, isSoftwareOnly = true, isHardwareAccelerated = false

        4. 判断设备是否支持某种编解码器

        可以使用以下方式判断设备是否支持某种编解码器：

        boolean isEncoder = true; // 是否为编码器
String mimeType = "video/avc"; // 媒体类型
MediaCodecInfo codecInfo = codecList.findCodecForType(mimeType);
if (codecInfo != null) { String name = codecInfo.getName();
    if (isEncoder) { MediaCodecInfo.CodecCapabilities capabilities = codecInfo.getCapabilitiesForType(mimeType);
        if (capabilities != null && capabilities.isEncoder()) { // 设备支持该编码器
        }
    } else { // 设备支持该解码器
    }
}

        其中，isEncoder 表示是否为编码器，mimeType 表示媒体类型。

        5. 查询默认的编解码器

        对于某种 MediaFormat，MediaCodecList 支持查询哪种 Codec 支持这种 Format：

        MediaCodecInfo codecInfo = codecList.findEncoderForFormat(format);
if (codecInfo != null) { String name = codecInfo.getName();
    // 使用默认编码器
}

        其中，format 表示媒体格式。

        三、通过 MediaCodecList 创建 MediaCodec

        3.1 创建解码器

        想要解码某个文件，首先要创建 MediaCodec 解码器，基本步骤是

        1. 创建 MediaCodecList 实例
        2. 使用 MediaExtractor 获取 Track 的 Format 信息
        3. 根据 Format 找到默认的解码器信息 MediaCodecInfo
        4. 根据 MediaCodecInfo 中的信息创建 MediaCodec

          代码如下：

        public class Decoder { public void decodeFile(String filePath) { MediaExtractor extractor = new MediaExtractor();
        try { extractor.setDataSource(filePath);
        } catch (IOException e) { e.printStackTrace();
        }
        // 获取文件中的第一个轨道
        MediaFormat format = extractor.getTrackFormat(0);
        String mime = format.getString(MediaFormat.KEY_MIME);
        // 使用 MediaCodecList 来找到支持这个媒体类型的解码器
        MediaCodecList codecList = new MediaCodecList(MediaCodecList.ALL_CODECS);
        String decoderName = codecList.findDecoderForFormat(format);
        // 创建 MediaCodec 解码器
        MediaCodec decoder = null;
        try { decoder = MediaCodec.createByCodecName(decoderName);
        } catch (IOException e) { e.printStackTrace();
        }
        // 配置解码器
        decoder.configure(format, null, null, 0);
        decoder.start();
        // ... 这里可以开始解码操作
    }
}

        3.2 创建编码器

        1. 创建 MediaCodecList 实例
        2. 构建 MediaFormat 用于描述目标编码的格式
        3. 通过 MediaCodecList 查询 MediaFormat 的默认编码器信息 MediaCodecInfo
        4. 根据 MediaCodecInfo 中的信息创建 MediaCodec

          代码如下：

        public class Encoder { public void encodeToFormat(String mimeType) { // 创建 MediaCodecList 实例
        MediaCodecList codecList = new MediaCodecList(MediaCodecList.ALL_CODECS);
        // 构建 MediaFormat 用于描述目标编码的格式
        MediaFormat format = MediaFormat.createVideoFormat(mimeType, 640, 480);
        // 通过 MediaCodecList 查询 MediaFormat 的默认编码器信息 MediaCodecInfo
        String encoderName = codecList.findEncoderForFormat(format);
        // 根据 MediaCodecInfo 中的信息创建 MediaCodec
        MediaCodec encoder = null;
        try { encoder = MediaCodec.createByCodecName(encoderName);
        } catch (IOException e) { e.printStackTrace();
        }
        // 配置编码器
        encoder.configure(format, null, null, MediaCodec.CONFIGURE_FLAG_ENCODE);
        encoder.start();
        // ... 这里可以开始编码操作
    }
}

        总结

        本文介绍了 MediaCodecList 的基本使用方法，并展示了如何使用 MediaCodecList 来创建 MediaCodec 编解码器。

        参考

        • MediaCodecList

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