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  • Safari sends excessive HTTP range requests during HTML5 MOV playback

    28 mai, par Lucy

    I am currently developing a web application based on React and Next.js, and I use the react-player library to play user-uploaded videos stored on AWS S3. The supported upload video formats are mp4, mov, and mkv, with codecs including H.264 or H.265 (HEVC).

    


    Problem

    


    However, some H.264 videos in the mov format exhibit noticeably poor playback performance only in the Safari browser. The videos do not play smoothly and frequently experience stuttering or delays.

    


    How Safari Handles Range Requests (As I Understand It) :

    


      

    1. Safari first sends a normal GET request to check if the server supports Range requests. If the server responds with the header Accept-Ranges : bytes, Safari closes the connection.

      2. 


    2. Then, Safari sends a very small range request like Range : bytes=0-1 to confirm it receives a 206 Partial Content response.

      3. 


    3. Next, Safari requests some parts from the beginning and the end of the file to locate metadata such as the moov atom in MP4 files.

      4. 


    4. After that, actual streaming begins, but Safari does not request the entire file at once ; instead, it divides the needed parts into multiple small Range requests.

      5. 


    


    Example of Actual Problematic Requests

    


    Below are some of the Range requests Safari makes for the problematic .mov video (H.264 codec) :

    


    # Request - 1
Connection: keep-alive
Range: bytes=0-1

# Response
HTTP/1.1 206 Partial Content
Accept-Ranges: bytes
Content-Disposition: attachment;filename*=utf-8''test.mov
Content-Length: 2
Content-Range: bytes 0-1/102801747
Content-Type: video/quicktime

-------------------------------------
# Request - 2
Connection: Keep-Alive
Range: bytes=0-102801746

# Response
HTTP/1.1 206 Partial Content
Accept-Ranges: bytes
Content-Disposition: attachment;filename*=utf-8''test.mov
Content-Length: 102801747
Content-Range: bytes 0-102801746/102801747
Content-Type: video/quicktime

-------------------------------------
# Request - 3
Connection: Keep-Alive
Range: bytes=102760448-102801746

# Response - 3
HTTP/1.1 206 Partial Content
Accept-Ranges: bytes
Content-Disposition: attachment;filename*=utf-8''test.mov
Content-Length: 41299
Content-Range: bytes 102760448-102801746/102801747
Content-Type: video/quicktime

-------------------------------------
# Request - 4
Connection: keep-alive
Range: bytes=3014656-3080191 # 64KB

# Response - 4
HTTP/1.1 206 Partial Content
Accept-Ranges: bytes
Content-Disposition: attachment;filename*=utf-8''IMG_7929.mov
Content-Length: 65536
Content-Range: bytes 3014656-3080191/102801747
Content-Type: video/quicktime


    


    Safari continues to send hundreds of similar small Range requests repeatedly, gradually downloading the file.

    


    This causes increased network load, which ultimately leads to video stuttering or playback delays.

    


    Example of another .mov file that works properly :

    


    In contrast, another .mov video using the same format and codec (H.264) sends Range requests over much larger byte ranges, downloading about 30MB of data at once. In this case, the video plays smoothly.

    


    # Request 
Connection: Keep-Alive
Range: bytes=1310534-673918954 # Request : 672MB, Actual Downloaded : 32MB

# Response
Accept-Ranges: bytes
Content-Disposition: attachment;filename*=utf-8''mov-example-video-download-4k-uhd-3840x2160.mov
Content-Length: 672608421
Content-Range: bytes 1310534-673918954/673918955
Content-Type: video/quicktime


    


    Question

    


    In Safari, for certain video files, the browser repeatedly closes the connection after receiving only a few kilobytes per request and immediately sends the next request. As a result, dozens or even hundreds of small range requests occur consecutively. This causes increased connection overhead and latency, and although the web server can deliver data at sufficient speed, the player does not receive data in time, leading to poor and stuttering video playback.

    


      

    1. What could be the reason Safari repeatedly makes these very small requests for certain files ?

      2. 


    2. Could the internal structure of the video file (such as the moov atom) influence this request pattern ?

      3. 


    


    f you have any similar experience or advice, please share.

    


    What I'ved tried

    


      

    • Using ffmpeg to move the moov atom to the beginning of the file with -movflags faststart does not resolve the issue — the same problem persists.

      • 


    • Converting the exact same video to MP4 format and testing it results in normal playback without issues.

      • 


    


    Test Environment

    


      

    • Macbook pro 16

      • 


    • mac OS - Sequoia 15.5

      • 


    • Safari - Latest

      • 


    


    File information

    


    Due to company policy, I am unable to share the problematic video files directly. However, I am attaching the file information obtained via ffprobe for your reference.

    


    ffprobe -v error -show_format -show_streams -print_format json test.mov

{
    "streams": [
        {
            "index": 0,
            "codec_name": "h264",
            "codec_long_name": "H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10",
            "profile": "High",
            "codec_type": "video",
            "codec_tag_string": "avc1",
            "codec_tag": "0x31637661",
            "width": 3840,
            "height": 2160,
            "coded_width": 3840,
            "coded_height": 2160,
            "closed_captions": 0,
            "film_grain": 0,
            "has_b_frames": 0,
            "pix_fmt": "yuv420p",
            "level": 51,
            "color_range": "tv",
            "color_space": "bt709",
            "color_transfer": "bt709",
            "color_primaries": "bt709",
            "chroma_location": "left",
            "field_order": "progressive",
            "refs": 1,
            "is_avc": "true",
            "nal_length_size": "4",
            "id": "0x1",
            "r_frame_rate": "30000/1001",
            "avg_frame_rate": "18200/607",
            "time_base": "1/600",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 10925,
            "duration": "18.208333",
            "bit_rate": "44900923",
            "bits_per_raw_sample": "8",
            "nb_frames": "546",
            "extradata_size": 158,
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "non_diegetic": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0,
                "multilayer": 0
            },
            "tags": {
                "creation_time": "",
                "language": "und",
                "handler_name": "Core Media Video",
                "vendor_id": "[0][0][0][0]",
                "encoder": "H.264"
            }
        },
        {
            "index": 1,
            "codec_name": "aac",
            "codec_long_name": "AAC (Advanced Audio Coding)",
            "profile": "LC",
            "codec_type": "audio",
            "codec_tag_string": "mp4a",
            "codec_tag": "0x6134706d",
            "sample_fmt": "fltp",
            "sample_rate": "44100",
            "channels": 2,
            "channel_layout": "stereo",
            "bits_per_sample": 0,
            "initial_padding": 0,
            "id": "0x2",
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/44100",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 802988,
            "duration": "18.208345",
            "bit_rate": "187218",
            "nb_frames": "787",
            "extradata_size": 2,
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "non_diegetic": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0,
                "multilayer": 0
            },
            "tags": {
                "creation_time": "",
                "language": "und",
                "handler_name": "Core Media Audio",
                "vendor_id": "[0][0][0][0]"
            }
        },
        {
            "index": 2,
            "codec_type": "data",
            "codec_tag_string": "mebx",
            "codec_tag": "0x7862656d",
            "id": "0x3",
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/600",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 10925,
            "duration": "18.208333",
            "bit_rate": "4",
            "nb_frames": "1",
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "non_diegetic": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0,
                "multilayer": 0
            },
            "tags": {
                "creation_time": "",
                "language": "und",
                "handler_name": "Core Media Metadata"
            }
        },
        {
            "index": 3,
            "codec_type": "data",
            "codec_tag_string": "mebx",
            "codec_tag": "0x7862656d",
            "id": "0x4",
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/600",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 10925,
            "duration": "18.208333",
            "bit_rate": "6756",
            "nb_frames": "80",
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "non_diegetic": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0,
                "multilayer": 0
            },
            "tags": {
                "creation_time": "",
                "language": "und",
                "handler_name": "Core Media Metadata"
            }
        },
        {
            "index": 4,
            "codec_type": "data",
            "codec_tag_string": "mebx",
            "codec_tag": "0x7862656d",
            "id": "0x5",
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/600",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 10925,
            "duration": "18.208333",
            "bit_rate": "50764",
            "nb_frames": "546",
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "non_diegetic": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0,
                "multilayer": 0
            },
            "tags": {
                "creation_time": "",
                "language": "und",
                "handler_name": "Core Media Metadata"
            }
        },
        {
            "index": 5,
            "codec_type": "data",
            "codec_tag_string": "mebx",
            "codec_tag": "0x7862656d",
            "id": "0x6",
            "r_frame_rate": "0/0",
            "avg_frame_rate": "0/0",
            "time_base": "1/600",
            "start_pts": 0,
            "start_time": "0.000000",
            "duration_ts": 10925,
            "duration": "18.208333",
            "bit_rate": "19",
            "nb_frames": "1",
            "disposition": {
                "default": 1,
                "dub": 0,
                "original": 0,
                "comment": 0,
                "lyrics": 0,
                "karaoke": 0,
                "forced": 0,
                "hearing_impaired": 0,
                "visual_impaired": 0,
                "clean_effects": 0,
                "attached_pic": 0,
                "timed_thumbnails": 0,
                "non_diegetic": 0,
                "captions": 0,
                "descriptions": 0,
                "metadata": 0,
                "dependent": 0,
                "still_image": 0,
                "multilayer": 0
            },
            "tags": {
                "creation_time": "",
                "language": "und",
                "handler_name": "Core Media Metadata"
            }
        }
    ],
    "format": {
        "filename": "test.mov",
        "nb_streams": 6,
        "nb_programs": 0,
        "nb_stream_groups": 0,
        "format_name": "mov,mp4,m4a,3gp,3g2,mj2",
        "format_long_name": "QuickTime / MOV",
        "start_time": "0.000000",
        "duration": "18.208345",
        "size": "102801747",
        "bit_rate": "45166871",
        "probe_score": 100,
        "tags": {
            "major_brand": "qt  ",
            "minor_version": "0",
            "compatible_brands": "qt  ",
            "creation_time": "",
            "com.apple.quicktime.location.accuracy.horizontal": "76.200233",
            "com.apple.quicktime.full-frame-rate-playback-intent": "0",
            "com.apple.quicktime.location.ISO6709": "",
            "com.apple.quicktime.make": "Apple",
            "com.apple.quicktime.model": "iPhone 15 Pro",
            "com.apple.quicktime.software": "18.4.1",
            "com.apple.quicktime.creationdate": ""
        }
    }
}


    


  • What is the bitrate of my audio file based on ffmpeg output ?

    21 avril 2015, par blueether

    Is it the 40kb/s under Format, or is it the 16kb/s under Stream ? What is the relationship between the Format and the Stream ?
    The below output is for a file generated using Core Audio on an iphone, with an Audio Unit. The output format was specified by an AudioStreamBasicDescription descriptor

    Updated :
    Output from ffprobe -v error -show_format -show_streams 123_1429602551009.051025.m4a :

    [STREAM]
    
index=0
    
codec_name=aac
    
codec_long_name=AAC (Advanced Audio Coding)
    
profile=LC
    
codec_type=audio
    
codec_time_base=1/8000
    
codec_tag_string=mp4a
    
codec_tag=0x6134706d
    
sample_fmt=fltp
    
sample_rate=8000
    
channels=1
    
channel_layout=mono
    
bits_per_sample=0
    
id=N/A
    
r_frame_rate=0/0
    
avg_frame_rate=0/0
    
time_base=1/8000
    
start_pts=0
    
start_time=0.000000
    
duration_ts=43008
    
duration=5.376000
    
bit_rate=16501
    
max_bit_rate=N/A
    
bits_per_raw_sample=N/A
    
nb_frames=42
    
nb_read_frames=N/A
    
nb_read_packets=N/A
    
DISPOSITION:default=1
    
DISPOSITION:dub=0
    
DISPOSITION:original=0
    
DISPOSITION:comment=0
    
DISPOSITION:lyrics=0
    
DISPOSITION:karaoke=0
    
DISPOSITION:forced=0
    
DISPOSITION:hearing_impaired=0
    
DISPOSITION:visual_impaired=0
    
DISPOSITION:clean_effects=0
    
DISPOSITION:attached_pic=0
    
TAG:creation_time=1970-04-16 22:36:01
    
TAG:language=eng
    
[/STREAM]
    
[FORMAT]
    
filename=123_1429602551009.051025.m4a
    
nb_streams=1
    
nb_programs=0
    
format_name=mov,mp4,m4a,3gp,3g2,mj2
    
format_long_name=QuickTime / MOV
    
start_time=0.000000
    
duration=5.376000
    
size=27473
    
bit_rate=40882
    
probe_score=100
    
TAG:major_brand=M4A
    
TAG:minor_version=0
    
TAG:compatible_brands=M4A mp42isom
    
TAG:creation_time=1970-04-16 22:36:01
    
TAG:iTunSMPB= 00000000 00000840 00000361 0000000000009C5F 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
    
[/FORMAT]

  • How do I upscale an iOS App Preview video to 1080 x 1920 ?

    30 août 2016, par Benjamin Thiel

    I just captured a video of my new app running on an iPhone 6 using QuickTime Player and a Lightning cable. Afterwards I created an App Preview project in iMovie, exported it and could successfully upload it to iTunes Connect.

    Apple requires developers to upload App Previews in different resolutions dependent on screen size, namely :

    • iPhone 5(S) : 1080 x 1920 or 640 x 1136
    • iPhone 6 : 750 x 1334 (what I have)
    • iPhone 6+ : 1080 x 1920

    Obviously, 1080 x 1920 is killing two birds with one stone. I know that upscaling isn’t the perfect solution, but it’s meeting my needs. Since I don’t own a 6+, another recording session won’t do the trick.

    Unfortunately, iTunes Connect is extremely picky about what to accept. Here’s what I tried, to no avail :

    • Handbrake, iMovie, QuickTime do not support upscaling
    • MPEG Streamclip
    • ffmpeg -i input.mp4 -acodec copy -vf scale=1080:1920 output.mp4

    Strangely enough, iTunes Connect keeps complaining about the wrong resolution when I try to upload the output.mp4 of ffmpeg.

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