Function ff_get_format

libavcodec/decode.c:1210–1346

}

int ff_get_format(AVCodecContext *avctx, const enum AVPixelFormat *fmt)
{
    const AVPixFmtDescriptor *desc;
    enum AVPixelFormat *choices;
    enum AVPixelFormat ret, user_choice;
    const AVCodecHWConfigInternal *hw_config;
    const AVCodecHWConfig *config;
    int i, n, err;

    // Find end of list.
    for (n = 0; fmt[n] != AV_PIX_FMT_NONE; n++);
    // Must contain at least one entry.
    av_assert0(n >= 1);
    // If a software format is available, it must be the last entry.
    desc = av_pix_fmt_desc_get(fmt[n - 1]);
    if (desc->flags & AV_PIX_FMT_FLAG_HWACCEL) {
        // No software format is available.
    } else {
        avctx->sw_pix_fmt = fmt[n - 1];
    }

    choices = av_memdup(fmt, (n + 1) * sizeof(*choices));
    if (!choices)
        return AV_PIX_FMT_NONE;

    for (;;) {
        // Remove the previous hwaccel, if there was one.
        ff_hwaccel_uninit(avctx);

        user_choice = avctx->get_format(avctx, choices);
        if (user_choice == AV_PIX_FMT_NONE) {
            // Explicitly chose nothing, give up.
            ret = AV_PIX_FMT_NONE;
            break;
        }

        desc = av_pix_fmt_desc_get(user_choice);
        if (!desc) {
            av_log(avctx, AV_LOG_ERROR, "Invalid format returned by "
                   "get_format() callback.\n");
            ret = AV_PIX_FMT_NONE;
            break;
        }
        av_log(avctx, AV_LOG_DEBUG, "Format %s chosen by get_format().\n",
               desc->name);

        for (i = 0; i < n; i++) {
            if (choices[i] == user_choice)
                break;
        }
        if (i == n) {
            av_log(avctx, AV_LOG_ERROR, "Invalid return from get_format(): "
                   "%s not in possible list.\n", desc->name);
            ret = AV_PIX_FMT_NONE;
            break;
        }

        if (ffcodec(avctx->codec)->hw_configs) {