PHP如何获取DASH流媒体信息 DASH流媒体解析技巧获取播放信息

<?php

$mpd_url = 'your_dash_mpd_url.mpd'; // 替换为你的MPD文件URL

$xml = new DOMDocument();
$xml->load($mpd_url);

// 检查是否成功加载
if (!$xml) {
    die('Failed to load MPD file.');
}

// 现在你可以使用XPath来查询特定的元素
$xpath = new DOMXPath($xml);

// 例如，获取所有Representation节点的带宽信息
$representations = $xpath->query('//Representation');

foreach ($representations as $representation) {
    $bandwidth = $representation->getAttribute('bandwidth');
    echo "Bandwidth: " . $bandwidth . "\n";
    // 还可以获取其他属性，如width, height, codecs等
    $width = $representation->getAttribute('width');
    $height = $representation->getAttribute('height');
    echo "Width: " . $width . ", Height: " . $height . "\n";
}

?>

<SegmentList duration="4000" timescale="1000">
    <SegmentURL media="segment1.m4s"/>
    <SegmentURL media="segment2.m4s"/>
    <SegmentURL media="segment3.m4s"/>
</SegmentList>

$segment_urls = $xpath->query('//SegmentList/SegmentURL');
foreach ($segment_urls as $segment_url) {
    $media_url = $segment_url->getAttribute('media');
    echo "Segment URL: " . $media_url . "\n";
}

<SegmentTemplate media="segment_$Number$.m4s" startNumber="1" timescale="1000" duration="4000"/>

$segment_template = $xpath->query('//SegmentTemplate')->item(0); // 获取第一个SegmentTemplate
$media_template = $segment_template->getAttribute('media');
$start_number = $segment_template->getAttribute('startNumber');
$duration = $segment_template->getAttribute('duration');
$timescale = $segment_template->getAttribute('timescale');

$number_of_segments = 10; // 假设有10个分片

for ($i = 0; $i < $number_of_segments; $i++) {
    $segment_number = $start_number + $i;
    $media_url = str_replace('$Number$', $segment_number, $media_template);
    echo "Segment URL: " . $media_url . "\n";
}

<?php

// ... (前面的MPD文件解析代码) ...

$representations = $xpath->query('//Representation');

$available_bitrates = [];
foreach ($representations as $representation) {
    $bandwidth = $representation->getAttribute('bandwidth');
    $width = $representation->getAttribute('width');
    $height = $representation->getAttribute('height');

    $available_bitrates[] = [
        'bandwidth' => $bandwidth,
        'width' => $width,
        'height' => $height
    ];
}

// 返回JSON格式的码率信息
header('Content-Type: application/json');
echo json_encode($available_bitrates);

?>