fix: read the stream quality from HLS variants without FRAME-RATE or CODECS

getStreamInfo returned a resolution only when the top variant of a master playlist had RESOLUTION, FRAME-RATE and CODECS, although playlist:format and playlist:update use only the height. RFC 8216 makes FRAME-RATE and CODECS optional, so such streams never got a quality. The parsing moves to parseStreamInfo, which tests can call without a network.

scripts/utils.ts

@@ -99,8 +99,8 @@ export function truncate(string: string, limit: number = 100) {
 type StreamInfo = {
   resolution: { width: number; height: number }
   bandwidth: number
-  frameRate: number
+  frameRate?: number
-  codecs: string
+  codecs?: string
 }
 
 export async function getStreamInfo(
@@ -162,6 +162,10 @@ export async function getStreamInfo(
 
   if (!data) return undefined
 
+  return parseStreamInfo(url, data)
+}
+
+export function parseStreamInfo(url: string, data: string): StreamInfo | undefined {
   let info: StreamInfo | undefined
 
   if (url.includes('.m3u8')) {
@@ -173,7 +177,7 @@ export async function getStreamInfo(
       if (playlist && playlist.isMasterPlaylist && playlist.variants.length) {
         const v = orderBy(playlist.variants, ['bandwidth'], ['desc'])[0]
 
-        if (v && v.resolution && v.frameRate && v.codecs) {
+        if (v && v.resolution) {
           info = {
             resolution: { width: v.resolution.width, height: v.resolution.height },
             bandwidth: v.bandwidth,

tests/utils.test.ts

@@ -0,0 +1,45 @@
+import { describe, it, expect } from 'vitest'
+import { parseStreamInfo } from '../scripts/utils'
+
+const url = 'https://example.com/live/playlist.m3u8'
+
+describe('parseStreamInfo', () => {
+  it('reads the resolution of a master playlist without FRAME-RATE', () => {
+    const playlist = [
+      '#EXTM3U',
+      '#EXT-X-STREAM-INF:BANDWIDTH=2128000,CODECS="avc1.4d401f,mp4a.40.2",RESOLUTION=1280x720',
+      'chunklist_720p.m3u8',
+      '#EXT-X-STREAM-INF:BANDWIDTH=1064000,CODECS="avc1.4d401e,mp4a.40.2",RESOLUTION=854x480',
+      'chunklist_480p.m3u8'
+    ].join('\n')
+
+    expect(parseStreamInfo(url, playlist)).toEqual({
+      resolution: { width: 1280, height: 720 },
+      bandwidth: 2128000,
+      frameRate: undefined,
+      codecs: 'avc1.4d401f,mp4a.40.2'
+    })
+  })
+
+  it('reads the resolution of a master playlist without CODECS', () => {
+    const playlist = [
+      '#EXTM3U',
+      '#EXT-X-STREAM-INF:BANDWIDTH=1500000,RESOLUTION=1024x576,FRAME-RATE=25.000',
+      'tracks-v1/mono.m3u8'
+    ].join('\n')
+
+    expect(parseStreamInfo(url, playlist)?.resolution).toEqual({ width: 1024, height: 576 })
+  })
+
+  it('returns nothing for a media playlist or a master playlist without RESOLUTION', () => {
+    const media = ['#EXTM3U', '#EXT-X-TARGETDURATION:6', '#EXTINF:6.0,', 'segment_1.ts'].join('\n')
+    const audioOnly = [
+      '#EXTM3U',
+      '#EXT-X-STREAM-INF:BANDWIDTH=128000,CODECS="mp4a.40.2"',
+      'audio.m3u8'
+    ].join('\n')
+
+    expect(parseStreamInfo(url, media)).toBeUndefined()
+    expect(parseStreamInfo(url, audioOnly)).toBeUndefined()
+  })
+})