即使在下载大块时存在延迟，ExoPlayer 也不会使用较低的比特率，这会导致冻结和缓冲

Question

根据我们的经验，即使在下载大块时存在延迟，ExoPlayer 也不会使用较低的比特率，这会导致冻结和缓冲。然而带宽是 6 Mbit，因为 VBR 有时一个 2 秒块的大小从 1.5 MegeByte 到 15 MegaByte 不等。根据我们的经验，当比特率增加时，播放器仍会尝试使用相同的比特率而不是降低比特率来下载下一个块。是什么导致了这个问题。有没有办法或配置来解决这个问题？

我们正在使用缓冲区大小和轨道选择持续时间的默认值。

private const val ADAPTIVE_MIN_DURATION_FOR_QUALITY_INCREASE_MS = 10000
private const val ADAPTIVE_MAX_DURATION_FOR_QUALITY_DECREASE_MS = 25000
private const val ADAPTIVE_MIN_DURATION_TO_RETAIN_AFTER_DISCARD_MS = 25000
private const val ADAPTIVE_BANDWIDTH_FRACTION = 0.70f
private const val ADAPTIVE_BUFFERED_FRACTION_TO_LIVE_EDGE_FOR_QUALITY_INCREASE = 0.75f

public static final int DEFAULT_MIN_BUFFER_MS = 50_000;
public static final int DEFAULT_MAX_BUFFER_MS = 50_000;
public static final int DEFAULT_BUFFER_FOR_PLAYBACK_MS = 2500;
public static final int DEFAULT_BUFFER_FOR_PLAYBACK_AFTER_REBUFFER_MS = 5000;

//MPD File

<?xml version="1.0" encoding="UTF-8"?>
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Answer 1

我为此做了一个解决方法。它主要工作。

protected boolean canSelectFormat(Format format, int trackBitrate, float playbackSpeed, long effectiveBitrate) {
    if (lastBufferEvaluationMediaChunk != null && trackBitrate == lastBufferEvaluationMediaChunk.trackFormat.bitrate) {
        long chunkDurationInSeconds = (lastBufferEvaluationMediaChunk.endTimeUs - lastBufferEvaluationMediaChunk.startTimeUs) / 1_000_000;
        double chunkBitrate = lastBufferEvaluationMediaChunk.bytesLoaded() / chunkDurationInSeconds * 8.0;

        double bitrateCoefficient = chunkBitrate / trackBitrate;
        if (bitrateCoefficient > 1.0f) {
            return Math.round(trackBitrate * playbackSpeed) * bitrateCoefficient <= effectiveBitrate;
        }
    }
    return Math.round(trackBitrate * playbackSpeed) <= effectiveBitrate;
}

即使在下载大块时存在延迟，ExoPlayer 也不会使用较低的比特率，这会导致冻结和缓冲

ExoPlayer does not use lower bitrate even there is latency in downloading big chunks and this causes freezing and buffering

android

mpd

android-tv

mpeg-dash

exoplayer2.x