Function libopus_encode_init

libavcodec/libopusenc.c:259–440

}

static av_cold int libopus_encode_init(AVCodecContext *avctx)
{
    LibopusEncContext *opus = avctx->priv_data;
    OpusMSEncoder *enc;
    uint8_t libopus_channel_mapping[255];
    int ret = OPUS_OK;
    int channels = avctx->ch_layout.nb_channels;
    int av_ret;
    int coupled_stream_count, header_size, frame_size;
    int mapping_family;

    frame_size = opus->opts.frame_duration * 48000 / 1000;
    switch (frame_size) {
    case 120:
    case 240:
        if (opus->opts.application != OPUS_APPLICATION_RESTRICTED_LOWDELAY)
            av_log(avctx, AV_LOG_WARNING,
                   "LPC mode cannot be used with a frame duration of less "
                   "than 10ms. Enabling restricted low-delay mode.\n"
                   "Use a longer frame duration if this is not what you want.\n");
        /* Frame sizes less than 10 ms can only use MDCT mode, so switching to
         * RESTRICTED_LOWDELAY avoids an unnecessary extra 2.5ms lookahead. */
        opus->opts.application = OPUS_APPLICATION_RESTRICTED_LOWDELAY;
    case 480:
    case 960:
    case 1920:
    case 2880:
#ifdef OPUS_FRAMESIZE_120_MS
    case 3840:
    case 4800:
    case 5760:
#endif
        opus->opts.packet_size =
        avctx->frame_size      = frame_size * avctx->sample_rate / 48000;
        break;
    default:
        av_log(avctx, AV_LOG_ERROR, "Invalid frame duration: %g.\n"
               "Frame duration must be exactly one of: 2.5, 5, 10, 20, 40"
#ifdef OPUS_FRAMESIZE_120_MS
               ", 60, 80, 100 or 120.\n",
#else
               " or 60.\n",
#endif
               opus->opts.frame_duration);
        return AVERROR(EINVAL);
    }

    if (avctx->compression_level < 0 || avctx->compression_level > 10) {
        av_log(avctx, AV_LOG_WARNING,
               "Compression level must be in the range 0 to 10. "
               "Defaulting to 10.\n");
        opus->opts.complexity = 10;
    } else {
        opus->opts.complexity = avctx->compression_level;
    }

    if (avctx->cutoff) {
        switch (avctx->cutoff) {