以下是一个使用ExoPlayer直接播放原始mp4（h264）片段的示例代码：

import android.net.Uri;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.google.android.exoplayer2.ExoPlayerFactory;
import com.google.android.exoplayer2.SimpleExoPlayer;
import com.google.android.exoplayer2.extractor.DefaultExtractorsFactory;
import com.google.android.exoplayer2.source.ExtractorMediaSource;
import com.google.android.exoplayer2.trackselection.AdaptiveTrackSelection;
import com.google.android.exoplayer2.trackselection.DefaultTrackSelector;
import com.google.android.exoplayer2.trackselection.TrackSelector;
import com.google.android.exoplayer2.ui.SimpleExoPlayerView;
import com.google.android.exoplayer2.upstream.BandwidthMeter;
import com.google.android.exoplayer2.upstream.DefaultBandwidthMeter;
import com.google.android.exoplayer2.upstream.DefaultDataSourceFactory;

public class MainActivity extends AppCompatActivity {

    private SimpleExoPlayerView simpleExoPlayerView;
    private SimpleExoPlayer player;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        simpleExoPlayerView = (SimpleExoPlayerView) findViewById(R.id.simple_exo_player_view);

        // 创建一个默认的TrackSelector
        BandwidthMeter bandwidthMeter = new DefaultBandwidthMeter();
        TrackSelector trackSelector = new DefaultTrackSelector(new AdaptiveTrackSelection.Factory(bandwidthMeter));

        // 创建ExoPlayer实例
        player = ExoPlayerFactory.newSimpleInstance(this, trackSelector);

        // 将player关联到simpleExoPlayerView
        simpleExoPlayerView.setPlayer(player);

        // 准备要播放的视频
        Uri videoUri = Uri.parse("your_mp4_video_url_here");
        DefaultDataSourceFactory dataSourceFactory = new DefaultDataSourceFactory(this, "ExoPlayerDemo");
        ExtractorMediaSource videoSource = new ExtractorMediaSource.Factory(dataSourceFactory)
                .setExtractorsFactory(new DefaultExtractorsFactory())
                .createMediaSource(videoUri);

        // 准备播放器
        player.prepare(videoSource);
        // 开始播放
        player.setPlayWhenReady(true);
    }

    @Override
    protected void onPause() {
        super.onPause();
        // 暂停播放
        player.setPlayWhenReady(false);
        // 释放播放器资源
        player.release();
    }
}

在上面的代码中，你需要将your_mp4_video_url_here替换为你想要播放的mp4视频的URL。此代码使用了ExoPlayer库来处理视频播放。它创建了一个ExoPlayer实例，将其关联到SimpleExoPlayerView上，并准备要播放的视频源。在onPause方法中，暂停播放并释放播放器资源。

请确保在项目的build.gradle文件中添加了ExoPlayer库的依赖：

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

其中2.X.X是你想要使用的ExoPlayer版本号。

希望这可以解决你的问题！