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<?php

/**
 * Youtube shortcode
 *
 * Contains shortcode + some improvements over the Core Embeds syntax (see http://codex.wordpress.org/Embeds )
 *
 * Examples:
 * [youtube https://www.youtube.com/watch?v=WVbQ-oro7FQ]
 * [youtube=http://www.youtube.com/watch?v=wq0rXGLs0YM&fs=1&hl=bg_BG&autohide=1&rel=0]
 * http://www.youtube.com/watch?v=H2Ncxw1xfck&w=320&h=240&fmt=1&rel=0&showsearch=1&hd=0
 * http://www.youtube.com/v/9FhMMmqzbD8?fs=1&hl=en_US
 * https://www.youtube.com/playlist?list=PLP7HaNDU4Cifov7C2fQM8Ij6Ew_uPHEXW
 *
 * @package Jetpack
 */

/* function youtube_embed_to_short_code() – Replaces YouTube embeds with YouTube shortcodes. */
add_filter( 'pre_kses', 'youtube_embed_to_short_code' );

/* function youtube_link() – Replaces plain-text links to YouTube videos with YouTube embeds. */

/* function youtube_link_callback() – Callback function for the regex that replaces YouTube URLs with
YouTube embeds. */


/**
 * Normalizes a YouTube URL to include a v= parameter and a query string free of encoded ampersands.
 *
 * @param string $url
 * @return string The normalized URL
 */
if ( ! function_exists( 'youtube_sanitize_url' ) ) :
/* function youtube_sanitize_url() – Normalizes a YouTube URL to include a v= parameter and a query string free of encoded ampersands. */
endif;

/* function youtube_id() – Converts a YouTube URL into an embedded YouTube video. */

/* function jetpack_shortcode_youtube_args() – Gets the args present in the YouTube shortcode URL. */

/* function youtube_shortcode() – Display the Youtube shortcode. */
add_shortcode( 'youtube', 'youtube_shortcode' );

/* function jetpack_amp_youtube_shortcode() – Renders the [youtube] shortcode as an AMP component. */

/* function jetpack_shortcode_youtube_dimensions() – Gets the dimensions of the [youtube] shortcode. */

/* function wpcom_youtube_embed_crazy_url() – For bare URLs on their own line of the form
http://www.youtube.com/v/9FhMMmqzbD8?fs=1&hl=en_US */

/* function wpcom_youtube_embed_crazy_url_init() – Add a new handler to automatically transform custom Youtube URLs (like playlists) into embeds. */
add_action( 'init', 'wpcom_youtube_embed_crazy_url_init' );

if (
  ! is_admin()
  
/**
 * Allow oEmbeds in Jetpack's Comment form.
 *
 * @module shortcodes
 *
 * @since 2.8.0
 *
 * @param int $allow_oembed Option to automatically embed all plain text URLs.
 */
  && apply_filters( 'jetpack_comments_allow_oembed', true )
  // No need for this on WordPress.com, this is done for multiple shortcodes at a time there.
  && ( ! defined( 'IS_WPCOM' ) || ! IS_WPCOM )
) {
  /*
	 * We attach wp_kses_post to comment_text in default-filters.php with priority of 10 anyway,
	 * so the iframe gets filtered out.
	 * Higher priority because we need it before auto-link and autop get to it.
	 */
  add_filter( 'comment_text', 'youtube_link', 1 );
}

/* function jetpack_fix_youtube_shortcode_display_filter() – Core changes to do_shortcode (https://core.trac.wordpress.org/changeset/34747) broke "improper" shortcodes
with the format [shortcode=http://url.com]. */
add_filter( 'the_content', 'jetpack_fix_youtube_shortcode_display_filter', 7 );
 

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