Method SetOutputFormat

src/core/audiosource.cpp:216–250

}

void FFMS_AudioSource::SetOutputFormat(FFMS_ResampleOptions const& opt) {
    if (opt.SampleRate != AP.SampleRate)
        throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_UNSUPPORTED,
            "Sample rate changes are currently unsupported.");

    // Cache stores audio in the output format, so clear it and reopen the file
    Cache.clear();
    PacketNumber = 0;
    OpenFile();
    avcodec_flush_buffers(CodecContext);

    BytesPerSample = av_get_bytes_per_sample(static_cast<AVSampleFormat>(opt.SampleFormat)) * PopCount(opt.ChannelLayout);
    NeedsResample =
        opt.SampleFormat != (int)CodecContext->sample_fmt ||
        opt.SampleRate != AP.SampleRate ||
        opt.ChannelLayout != AP.ChannelLayout ||
        opt.ForceResample;

    if (!NeedsResample) return;

    SwrContext *rawCtx = swr_alloc();

    AVChannelLayout ChLayoutOut = { AV_CHANNEL_ORDER_NATIVE, PopCount(opt.ChannelLayout), static_cast<uint64_t>(opt.ChannelLayout), nullptr };
    AVChannelLayout ChLayoutIn = { AV_CHANNEL_ORDER_NATIVE, PopCount(AP.ChannelLayout), static_cast<uint64_t>(AP.ChannelLayout), nullptr };
    swr_alloc_set_opts2(&rawCtx, &ChLayoutOut, (AVSampleFormat)opt.SampleFormat, opt.SampleRate, &ChLayoutIn, CodecContext->sample_fmt, AP.SampleRate, 0, nullptr);

    FFResampleContext newContext{ rawCtx };

    SetOptions(opt, newContext.get(), resample_options);

    if (swr_init(newContext.get()))
        throw FFMS_Exception(FFMS_ERROR_RESAMPLING, FFMS_ERROR_UNKNOWN,
            "Could not open avresample context");
    newContext.swap(ResampleContext);
}

std::unique_ptr<FFMS_ResampleOptions> FFMS_AudioSource::CreateResampleOptions() const {
    auto ret = ReadOptions(ResampleContext.get(), resample_options);