text: /*
   *  Copyright (c) 2013 The WebM project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree. An additional intellectual property rights grant can be found
   *  in the file PATENTS.  All contributing project authors may
   *  be found in the AUTHORS file in the root of the source tree.
   */
  
  #include "./warnings.h"
  
  #include <assert.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "vpx/vpx_encoder.h"
  
  #include "./tools_common.h"
  #include "./vpxenc.h"
  
  static const char quantizer_warning_string[] =
      "Bad quantizer values. Quantizer values should not be equal, and should "
      "differ by at least 8.";
  static const char lag_in_frames_with_realtime[] =
      "Lag in frames is ignored when deadline is set to realtime for cbr mode.";
  
  struct WarningListNode {
    const char *warning_string;
    struct WarningListNode *next_warning;
  };
  
  struct WarningList {
    struct WarningListNode *warning_node;
  };
  
  static void add_warning(const char *warning_string,
                          struct WarningList *warning_list) {
    struct WarningListNode **node = &warning_list->warning_node;
  
    struct WarningListNode *new_node = malloc(sizeof(*new_node));
    if (new_node == NULL) {
      fatal("Unable to allocate warning node.");
    }
  
    new_node->warning_string = warning_string;
    new_node->next_warning = NULL;
  
    while (*node != NULL) node = &(*node)->next_warning;
  
    *node = new_node;
  }
  
  static void free_warning_list(struct WarningList *warning_list) {
    while (warning_list->warning_node != NULL) {
      struct WarningListNode *const node = warning_list->warning_node;
      warning_list->warning_node = node->next_warning;
      free(node);
    }
  }
  
  static int continue_prompt(int num_warnings) {
    int c;
    fprintf(stderr,
            "%d encoder configuration warning(s). Continue? (y to continue) ",
            num_warnings);
    c = getchar();
    return c == 'y';
  }
  
  static void check_quantizer(int min_q, int max_q,
                              struct WarningList *warning_list) {
    const int lossless = min_q == 0 && max_q == 0;
    if (!lossless && (min_q == max_q || abs(max_q - min_q) < 8))
      add_warning(quantizer_warning_string, warning_list);
  }
  
  static void check_lag_in_frames_realtime_deadline(
      int lag_in_frames, int deadline, int rc_end_usage,
      struct WarningList *warning_list) {
    if (deadline == VPX_DL_REALTIME && lag_in_frames != 0 && rc_end_usage == 1)
      add_warning(lag_in_frames_with_realtime, warning_list);
  }
  
  void check_encoder_config(int disable_prompt,
                            const struct VpxEncoderConfig *global_config,
                            const struct vpx_codec_enc_cfg *stream_config) {
    int num_warnings = 0;
    struct WarningListNode *warning = NULL;
    struct WarningList warning_list = { 0 };
  
    check_quantizer(stream_config->rc_min_quantizer,
                    stream_config->rc_max_quantizer, &warning_list);
    check_lag_in_frames_realtime_deadline(
        stream_config->g_lag_in_frames, global_config->deadline,
        stream_config->rc_end_usage, &warning_list);
    /* Count and print warnings. */
    for (warning = warning_list.warning_node; warning != NULL;
         warning = warning->next_warning, ++num_warnings) {
      warn(warning->warning_string);
    }
  
    free_warning_list(&warning_list);
  
    if (num_warnings) {
      if (!disable_prompt && !continue_prompt(num_warnings)) exit(EXIT_FAILURE);
    }
  }
  