claincly 85ce0bc181 Add SSIM helper for transcoding quality measurements.
We use SSIM to measure the transcoding quality between. SSIM is a widely used
tool that compares the luma channel between two images, and generates a score
from 0 to 1 that indicates "how similar" the two images are.

In `SsimHelper`, we decode the two videos, extract matching frames and
calculates the mean SSIM (SSIM averaged all matching frames) for both videos.
Matching frames are referred to as "comparisonFrame" in the CL, which is
selected based on the frame number and a user-set comparison interval.
For instance, if the interval is 7, then every seventh frames are compared.

We use MediaCodec/MediaExtractor to decode the video, and use ImageReader to
extract the decoded frame.

The SSIM calculation logic is a inspired by and modified from the CTS
[MSSIMMatcher](https://cs.android.com/android/platform/superproject/+/master:cts/tests/tests/uirendering/src/android/uirendering/cts/bitmapcomparers/MSSIMComparer.java;l=1?q=mssimcom)
that has some errors and extra features we don't need (like handling RGB
images).

Adds TranscodeQualityTest to ensure high quality transcoding.

PiperOrigin-RevId: 430951206
2022-03-01 10:00:32 +00:00
2022-02-23 16:28:08 +00:00
2021-02-23 16:53:06 +00:00
2021-11-01 16:24:56 +00:00
2021-10-26 14:15:54 +01:00
2021-10-26 14:19:43 +01:00
2022-03-01 09:39:29 +00:00
2022-03-01 09:39:29 +00:00
2014-06-16 12:56:04 +01:00
2022-03-01 09:49:59 +00:00
2021-11-05 11:44:08 +00:00

ExoPlayer

ExoPlayer is an application level media player for Android. It provides an alternative to Androids MediaPlayer API for playing audio and video both locally and over the Internet. ExoPlayer supports features not currently supported by Androids MediaPlayer API, including DASH and SmoothStreaming adaptive playbacks. Unlike the MediaPlayer API, ExoPlayer is easy to customize and extend, and can be updated through Play Store application updates.

Documentation

Using ExoPlayer

ExoPlayer modules can be obtained from the Google Maven repository. It's also possible to clone the repository and depend on the modules locally.

From the Google Maven repository

1. Add ExoPlayer module dependencies

The easiest way to get started using ExoPlayer is to add it as a gradle dependency in the build.gradle file of your app module. The following will add a dependency to the full library:

implementation 'com.google.android.exoplayer:exoplayer:2.X.X'

where 2.X.X is your preferred version.

As an alternative to the full library, you can depend on only the library modules that you actually need. For example the following will add dependencies on the Core, DASH and UI library modules, as might be required for an app that only plays DASH content:

implementation 'com.google.android.exoplayer:exoplayer-core:2.X.X'
implementation 'com.google.android.exoplayer:exoplayer-dash:2.X.X'
implementation 'com.google.android.exoplayer:exoplayer-ui:2.X.X'

When depending on individual modules they must all be the same version.

The available library modules are listed below. Adding a dependency to the full ExoPlayer library is equivalent to adding dependencies on all of the library modules individually.

  • exoplayer-core: Core functionality (required).
  • exoplayer-dash: Support for DASH content.
  • exoplayer-hls: Support for HLS content.
  • exoplayer-rtsp: Support for RTSP content.
  • exoplayer-smoothstreaming: Support for SmoothStreaming content.
  • exoplayer-transformer: Media transformation functionality.
  • exoplayer-ui: UI components and resources for use with ExoPlayer.

In addition to library modules, ExoPlayer has extension modules that depend on external libraries to provide additional functionality. Some extensions are available from the Maven repository, whereas others must be built manually. Browse the extensions directory and their individual READMEs for details.

More information on the library and extension modules that are available can be found on the Google Maven ExoPlayer page.

2. Turn on Java 8 support

If not enabled already, you also need to turn on Java 8 support in all build.gradle files depending on ExoPlayer, by adding the following to the android section:

compileOptions {
  targetCompatibility JavaVersion.VERSION_1_8
}

3. Enable multidex

If your Gradle minSdkVersion is 20 or lower, you should enable multidex in order to prevent build errors.

Locally

Cloning the repository and depending on the modules locally is required when using some ExoPlayer extension modules. It's also a suitable approach if you want to make local changes to ExoPlayer, or if you want to use a development branch.

First, clone the repository into a local directory:

git clone https://github.com/google/ExoPlayer.git
cd ExoPlayer

Next, add the following to your project's settings.gradle file, replacing path/to/exoplayer with the path to your local copy:

gradle.ext.exoplayerModulePrefix = 'exoplayer-'
apply from: file("path/to/exoplayer/core_settings.gradle")

You should now see the ExoPlayer modules appear as part of your project. You can depend on them as you would on any other local module, for example:

implementation project(':exoplayer-library-core')
implementation project(':exoplayer-library-dash')
implementation project(':exoplayer-library-ui')

Developing ExoPlayer

Project branches

  • Development work happens on the dev-v2 branch. Pull requests should normally be made to this branch.
  • The release-v2 branch holds the most recent release.

Using Android Studio

To develop ExoPlayer using Android Studio, simply open the ExoPlayer project in the root directory of the repository.

Description
About Jetpack Media3 support libraries for media use cases, including ExoPlayer, an extensible media player for Android
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