Bug 226314 - IOS Native player caption font size is varying from small to big as the video plays in full screen
Summary: IOS Native player caption font size is varying from small to big as the video...
Status: NEW
Alias: None
Product: WebKit
Classification: Unclassified
Component: Media (show other bugs)
Version: Safari 14
Hardware: iPhone / iPad iOS 14
: P2 Minor
Assignee: Nobody
URL:
Keywords: InRadar
Depends on:
Blocks:
 
Reported: 2021-05-26 20:44 PDT by Karthik Sundari
Modified: 2021-06-02 20:45 PDT (History)
4 users (show)

See Also:

Attachments
Test video showing varying captions (37.26 MB, video/quicktime)
2021-05-26 20:44 PDT, Karthik Sundari 		no flags Details
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Description Karthik Sundari 2021-05-26 20:44:24 PDT 
Created attachment 429838 [details]
Test video showing varying captions

When an HLS(M3U8) live stream with closed captions is played on the native player in full-screen landscape mode. The captions seem to vary from small to big causing a bad UX experience. Please find a sample manifest. 

```
#EXTM3U
#EXT-X-VERSION:4
#EXT-X-MEDIA:TYPE=CLOSED-CAPTIONS,GROUP-ID="cc",NAME="English",LANGUAGE="en",DEFAULT=YES,AUTOSELECT=YES,INSTREAM-ID="CC1"
#EXT-X-STREAM-INF:BANDWIDTH=762800,CLOSED-CAPTIONS="cc",PROGRAM-ID=1,CODECS="avc1.4d401f,mp4a.40.5",RESOLUTION=512x288
EMP_CH4/track-muxed-repid-root_audio_video3-tc-.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=1018000,CLOSED-CAPTIONS="cc",PROGRAM-ID=1,CODECS="avc1.4d401f,mp4a.40.5",RESOLUTION=640x360
EMP_CH4/track-muxed-repid-root_audio_video2-tc-.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=2290400,CLOSED-CAPTIONS="cc",PROGRAM-ID=1,CODECS="avc1.4d401f,mp4a.40.5",RESOLUTION=1280x720
EMP_CH4/track-muxed-repid-root_audio_video1-tc-.m3u8
#EXT-X-STREAM-INF:BANDWIDTH=3635600,CLOSED-CAPTIONS="cc",PROGRAM-ID=1,CODECS="avc1.640020,mp4a.40.5",RESOLUTION=1280x720
EMP_CH4/track-muxed-repid-root_audio_video0-tc-.m3u8

#EXT-X-I-FRAME-STREAM-INF:BANDWIDTH=352360,PROGRAM-ID=1,CODECS="avc1.640020",RESOLUTION=1280x720,URI="*****/track-iframe-repid-iframe0-tc-.m3u8"
```
Comment 1 Radar WebKit Bug Importer 2021-06-02 20:45:23 PDT 
<rdar://problem/78796280>