media3/demos/transformer
andrewlewis cc046d5ce7 Remove most nullness marking from Transformer demos
The nullness checking is very verbose and redundant in some places, for
example, the ensures-non-null marking in the transformer activity, and it makes
changing features in the demo app more time consuming. The cost/benefit balance
seems to be in favor of removing this for demo code.

Note: the ExoPlayer main demo has nullness checks turned off.
PiperOrigin-RevId: 641890618
2024-06-10 07:14:10 -07:00
..

Transformer demo

This app demonstrates how to use the Transformer API to modify videos, for example by removing audio or video.

See the demos README for instructions on how to build and run this demo.

MediaPipe frame processing demo

Building the demo app with MediaPipe integration enabled requires some extra manual steps.

  1. Follow the instructions to install MediaPipe.

  2. Copy the Transformer demo's build configuration and MediaPipe graph text protocol buffer under the MediaPipe source tree. This makes it easy to build an AAR with bazel by reusing MediaPipe's workspace.

    cd "<path to MediaPipe checkout>"
    MEDIAPIPE_ROOT="$(pwd)"
    MEDIAPIPE_TRANSFORMER_ROOT="${MEDIAPIPE_ROOT}/mediapipe/java/com/google/mediapipe/transformer"
    cd "<path to the transformer demo (containing this readme)>"
    TRANSFORMER_DEMO_ROOT="$(pwd)"
    mkdir -p "${MEDIAPIPE_TRANSFORMER_ROOT}"
    mkdir -p "${TRANSFORMER_DEMO_ROOT}/libs"
    cp ${TRANSFORMER_DEMO_ROOT}/BUILD.bazel ${MEDIAPIPE_TRANSFORMER_ROOT}/BUILD
    cp ${TRANSFORMER_DEMO_ROOT}/src/withMediaPipe/assets/edge_detector_mediapipe_graph.pbtxt \
      ${MEDIAPIPE_TRANSFORMER_ROOT}
    
  3. Build the AAR and the binary proto for the demo's MediaPipe graph, then copy them to Transformer.

    cd ${MEDIAPIPE_ROOT}
    bazel build -c opt --strip=ALWAYS \
      --host_crosstool_top=@bazel_tools//tools/cpp:toolchain \
      --fat_apk_cpu=arm64-v8a,armeabi-v7a \
      --legacy_whole_archive=0 \
      --features=-legacy_whole_archive \
      --copt=-fvisibility=hidden \
      --copt=-ffunction-sections \
      --copt=-fdata-sections \
      --copt=-fstack-protector \
      --copt=-Oz \
      --copt=-fomit-frame-pointer \
      --copt=-DABSL_MIN_LOG_LEVEL=2 \
      --linkopt=-Wl,--gc-sections,--strip-all \
      mediapipe/java/com/google/mediapipe/transformer:edge_detector_mediapipe_aar.aar
    cp bazel-bin/mediapipe/java/com/google/mediapipe/transformer/edge_detector_mediapipe_aar.aar \
      ${TRANSFORMER_DEMO_ROOT}/libs
    bazel build mediapipe/java/com/google/mediapipe/transformer:edge_detector_binary_graph
    cp bazel-bin/mediapipe/java/com/google/mediapipe/transformer/edge_detector_mediapipe_graph.binarypb \
      ${TRANSFORMER_DEMO_ROOT}/src/withMediaPipe/assets
    
  4. In Android Studio, gradle sync and select the withMediaPipe build variant (this will only appear if the AAR is present), then build and run the demo app and select a MediaPipe-based effect.