Fix playback after seek

[derpoliuk]

Use estimated byte offset (if available) instead of calculated byte offset (Close #273).

Issue

I create STKAudioPlayer with URL to mp3 file. File duration is 38:05 (2285 s). After seeking to 37:40 (2260 s), player stopped.

Solution

After debugging player I figured out that offset is missing after seek: 6d00aa0#diff-b23113711075e5d630996cbb4e38dfe7L1500

I guess it was a typo and I removed ! before (ioFlags & kAudioFileStreamSeekFlag_OffsetIsEstimated). But this caused another issue: seek started working as expected, but progress was off.

For example after seeking to 37:40 (2260 s), progress was 37:15 (2235 s), not 37:40 (2260 s). The difference was exact value of delta variable. So I removed this code and now it works as expected.

Important

I test this code only with mp3 files and I don't know how it'll work with other formats.

[derpoliuk]

@tumtumtum I updated commit and PR's description.

[chuckkreuser]

@derpoliuk I've been stuck on this for a while when trying to stream mp3s. I'm glad your fix works for you. I tried and it's still the broken for me.

I'm curious, how are you instantiating the player? I've tried { .flushQueueOnSeek = YES } and { .gracePeriodAfterSeekInSeconds = 5.0f } but no luck.

Also, are you just calling play or queueing your mp3s? I'm not sure if that would make a difference, just trying different things.

Thanks

[derpoliuk]

@chuckkreuser, I've been stuck on this for a while when trying to stream mp3s.

I didn't try mp3s, only mp3.

I'm curious, how are you instantiating the player?

static func player(withDelegate delegate: STKAudioPlayerDelegate) -> STKAudioPlayer {
    let player = STKAudioPlayer(options: (STKAudioPlayerOptions(flushQueueOnSeek: true, enableVolumeMixer: false, equalizerBandFrequencies: (50, 100, 200, 400, 800, 1600, 2600, 3200, 4800, 5600, 6400, 7200, 8200, 9200, 11200, 12800, 13200, 14200, 15000, 15600, 16400, 17200, 18200, 1900), readBufferSize: 0, bufferSizeInSeconds: 30, secondsRequiredToStartPlaying: 0.5, gracePeriodAfterSeekInSeconds: 0.5, secondsRequiredToStartPlayingAfterBufferUnderun: 0.5)))
    player.meteringEnabled = true
    player.volume = 1
    player.delegate = delegate
    return player
}

I'm glad your fix works for you. I tried and it's still the broken for me.

This change did fix seek on some files, but on other files playback was really broken after seek - I hear only loud noice instead of audio file.

I tried to fix it and reverted back to previous version.

[chuckkreuser]

@derpoliuk Ah I see, thanks for your feedback.