ffmpeg AVChapter problems

sample_chapters.c

	/**
	 * This code is designed to create 5 chapters that are each 1 second apart, and then
	 * set its metadata to 'Chapter #'.
	 *
	 * There are two problems happening:
	 *
	 * 1) The chapter titles are all set to whatever the last metadata entry is. In this
	 *    case, they are all 'Chapter 5'.
	 *
	 * 2) The range of the chapters is wrong for all of them. They should be 0:00 to 0:01,
	 *    0:01 to 0:02, etc.
	 *
	 * See ffprobe output below for what the output is.
	 */

	unsigned int num_chapters = 5;
	unsigned int chapter_ix = 0;
	unsigned char chapter_title[80];
	memset(chapter_title, '\0', 80);

	AVChapter *chapter = calloc(1, sizeof(AVChapter));

	chapter->time_base.num = 1;
	chapter->time_base.den = 1000;

	AVChapter **chapters = calloc(num_chapters, sizeof(AVChapter*));

	for(chapter_ix = 0; chapter_ix < num_chapters; chapter_ix++) {

		chapter->id = chapter_ix + 1;
		chapter->start = 1000 * chapter_ix;
		chapter->end = chapter->start + 1000;

		printf("chapter range: %i-%i\n", chapter->start, chapter->end);

		sprintf(chapter_title, "Chapter %u", chapter_ix + 1);

		av_dict_set(&chapter->metadata, "title", chapter_title, 0);

		chapters[chapter_ix] = chapter;

	}

	output->nb_chapters = num_chapters;

	output->chapters = chapters;

	/**

	ffprobe output:

	 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'dvd_rip_00.mp4':
	  Metadata:
	    major_brand     : isom
	    minor_version   : 512
	    compatible_brands: isomiso2avc1mp41
	    encoder         : Lavf58.45.100
	  Duration: 00:00:05.00, start: 0.000000, bitrate: 9020 kb/s
	    Chapter #0:0: start 0.000000, end 4.000000
	    Metadata:
	      title           : Chapter 5
	    Chapter #0:1: start 4.000000, end 4.000000
	    Metadata:
	      title           : Chapter 5
	    Chapter #0:2: start 4.000000, end 4.000000
	    Metadata:
	      title           : Chapter 5
	    Chapter #0:3: start 4.000000, end 4.000000
	    Metadata:
	      title           : Chapter 5
	    Chapter #0:4: start 4.000000, end 5.000000
	    Metadata:
	      title           : Chapter 5

	*/

Forgot to add, I'm using ffmpeg 4.3.1