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• sws_scale performance comparison to media players real time resize

  14 juillet 2018, par Andrey Katkov

  While playing 4K video user can resize players window - and result image will be scaled smoothly in run time.

  On the other hand - program written with libav which reads 4k video file frame by frame and scale it down with sws_scale function do it less effective : it took more time then video duration to resize it.

  Why is it so ? Maybe because player fps is less and some frames are skipped - but video still looks smooth ?

• Invalid data stream in media could not be discarded by FFMPEG. Why is it staying and how to discard it ?

  5 décembre 2020, par Link-akro

  I have downloaded a [short media][1] i intend to convert then i will use the result as basis to practice and test any and all FFMPEG commands i learn or use later.

  


  That video seems to have an unknown invalid stream which never disappears no matter everything i tried to discard it. When i try to work with it later i get various problems like missing codec or no stream which is not the focus here but the reason why i got stubborn to remove the things i cannot deal with.

  


  The following probing prints a warning in yellow color on last row.

  


   > ffprobe -hide_banner -show_streams Movie_Countdown-youtube_I1vMKZ1kvg0.mov

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'Movie_Countdown-youtube_I1vMKZ1kvg0.mov':
  Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    creation_time   : 2015-05-20T13:45:55.000000Z
  Duration: 00:00:10.00, start: 0.000000, bitrate: 11474 kb/s
    Stream #0:0(eng): Video: h264 (Main) (avc1 / 0x31637661), yuv420p(tv, bt709), 1920x1080, 9930 kb/s, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 25 tbn, 50 tbc (default)
    Metadata:
      creation_time   : 2015-05-20T13:45:55.000000Z
      handler_name    : Apple Video Media Handler
      encoder         : H.264
      timecode        : 00:00:00:00
    Stream #0:1(eng): Audio: pcm_s16le (sowt / 0x74776F73), 48000 Hz, stereo, s16, 1536 kb/s (default)
    Metadata:
      creation_time   : 2015-05-20T13:45:56.000000Z
      handler_name    : Apple Sound Media Handler
      timecode        : 00:00:00:00
    Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s (default)
    Metadata:
      creation_time   : 2015-05-20T13:46:11.000000Z
      handler_name    : Time Code Media Handler
      timecode        : 00:00:00:00
Unsupported codec with id 0 for input stream 2


  


  Below the streams output. I split the text so you see the warning without searching in the middle.

  


  [STREAM]
index=0
codec_name=h264
codec_long_name=H.264 / AVC / MPEG-4 AVC / MPEG-4 part 10
profile=Main
codec_type=video
codec_time_base=1/50
codec_tag_string=avc1
codec_tag=0x31637661
width=1920
height=1080
coded_width=1920
coded_height=1088
closed_captions=0
has_b_frames=0
sample_aspect_ratio=1:1
display_aspect_ratio=16:9
pix_fmt=yuv420p
level=40
color_range=tv
color_space=bt709
color_transfer=bt709
color_primaries=bt709
chroma_location=left
field_order=unknown
timecode=N/A
refs=1
is_avc=true
nal_length_size=4
id=N/A
r_frame_rate=25/1
avg_frame_rate=25/1
time_base=1/25
start_pts=0
start_time=0.000000
duration_ts=250
duration=10.000000
bit_rate=9930739
max_bit_rate=N/A
bits_per_raw_sample=8
nb_frames=250
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
DISPOSITION:timed_thumbnails=0
TAG:creation_time=2015-05-20T13:45:55.000000Z
TAG:language=eng
TAG:handler_name=Apple Video Media Handler
TAG:encoder=H.264
TAG:timecode=00:00:00:00
[/STREAM]
[STREAM]
index=1
codec_name=pcm_s16le
codec_long_name=PCM signed 16-bit little-endian
profile=unknown
codec_type=audio
codec_time_base=1/48000
codec_tag_string=sowt
codec_tag=0x74776f73
sample_fmt=s16
sample_rate=48000
channels=2
channel_layout=stereo
bits_per_sample=16
id=N/A
r_frame_rate=0/0
avg_frame_rate=0/0
time_base=1/48000
start_pts=0
start_time=0.000000
duration_ts=480000
duration=10.000000
bit_rate=1536000
max_bit_rate=N/A
bits_per_raw_sample=N/A
nb_frames=480000
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
DISPOSITION:timed_thumbnails=0
TAG:creation_time=2015-05-20T13:45:56.000000Z
TAG:language=eng
TAG:handler_name=Apple Sound Media Handler
TAG:timecode=00:00:00:00
[/STREAM]
[STREAM]
index=2
codec_name=unknown
codec_long_name=unknown
profile=unknown
codec_type=data
codec_tag_string=tmcd
codec_tag=0x64636d74
id=N/A
r_frame_rate=0/0
avg_frame_rate=25/1
time_base=1/25
start_pts=0
start_time=0.000000
duration_ts=250
duration=10.000000
bit_rate=3
max_bit_rate=N/A
bits_per_raw_sample=N/A
nb_frames=1
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
DISPOSITION:timed_thumbnails=0
TAG:creation_time=2015-05-20T13:46:11.000000Z
TAG:language=eng
TAG:handler_name=Time Code Media Handler
TAG:timecode=00:00:00:00
[/STREAM]


  


  I scaled it down and recoded it for starters and i tried to discard the data stream with -dn and failed other methods i will mention at the end.
The output so far suggests that discarding should have worked since alternative datas are 0kB and no stream 2 is listed.

  


   > ffmpeg -hide_banner -dn -i C:\Users\admin-dix\Downloads\Movie_Countdown-youtube_I1vMKZ1kvg0.mov -vf "scale=h=450:w=800" -f mp4 -c:a aac -c:v libx264 mov_countdown.mp4

Output #0, mp4, to 'mov_countdown.mp4':
  Metadata:
    major_brand     : qt
    minor_version   : 537199360
    compatible_brands: qt
    encoder         : Lavf58.45.100
    Stream #0:0(eng): Video: h264 (libx264) (avc1 / 0x31637661), yuv420p(progressive), 800x450 [SAR 1:1 DAR 16:9], q=-1--1, 0.04 fps, 12800 tbn, 25 tbc (default)
    Metadata:
      creation_time   : 2015-05-20T13:45:55.000000Z
      handler_name    : Apple Video Media Handler
      timecode        : 00:00:00:00
      encoder         : Lavc58.91.100 libx264
    Side data:
      cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: N/A
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 128 kb/s (default)
    Metadata:
      creation_time   : 2015-05-20T13:45:56.000000Z
      handler_name    : Apple Sound Media Handler
      timecode        : 00:00:00:00
      encoder         : Lavc58.91.100 aac
frame=  250 fps= 43 q=-1.0 Lsize=     342kB time=00:00:10.00 bitrate= 280.1kbits/s speed= 1.7x
video:175kB audio:159kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 2.710857%


  


  Then ffprobe disagrees, there is still the stream and the warning.

  


  ffprobe mov_countdown.mp4

Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'mov_countdown.mp4':
  Metadata:
    major_brand     : isom
    minor_version   : 512
    compatible_brands: isomiso2avc1mp41
    encoder         : Lavf58.45.100
  Duration: 00:00:10.02, start: 0.000000, bitrate: 279 kb/s
    Stream #0:0(eng): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 800x450 [SAR 1:1 DAR 16:9], 142 kb/s, 25 fps, 25 tbr, 12800 tbn, 50 tbc (default)
    Metadata:
      handler_name    : Apple Video Media Handler
      timecode        : 00:00:00:00
    Stream #0:1(eng): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 129 kb/s (default)
    Metadata:
      handler_name    : Apple Sound Media Handler
    Stream #0:2(eng): Data: none (tmcd / 0x64636D74), 0 kb/s
    Metadata:
      handler_name    : Apple Video Media Handler
      timecode        : 00:00:00:00
Unsupported codec with id 0 for input stream 2


  


  I tried negative mapping as per this answer -map 0:d which failed. I did not understand -discard option as ffmpeg documentation refers to from the -vn,-an,-dn entries as it does not specify a stream.

  


  Why does it do that and how can i remove that stream i do not know and do not want to care about in future tests ?

  


  [1] : Clean Retro Movie Countdown - YouTube from Philippe Moesch https://www.youtube.com/watch?v=I1vMKZ1kvg0

  


• Read ID3 tags generated using Apple's id3taggenerator

  9 octobre 2024, par Damiaan Dufaux

  Hi I am creating an HLS stream with ID3 tags using Apple's HTTP Live Streaming (HLS) Tools, FFmpeg and NodeJS. When I try to read out the stream using an AVPlayer and AVPlayerItemMetadataOutput on macOS I'm not able to read out the ID3 tags. When I use the same code to read out a sample stream containing ID3 tags I do see them popping up. What am I doing wrong ?

  


  Reproduction :

  


  Streaming

  


  I generate an infinite HLS stream from a 5 minute long mpeg ts file using this command :

  


  ffmpeg -stream_loop -1 -re -i 5m.ts -c:v copy -c:a copy -f mpegts -strict -2 - | mediastreamsegmenter -b http://DamiaanTheoPro14.local:8081/ -f /tmp/hlsId3/video -D -m -M 50000 -log /tmp/hlsId3/log.txt


  


  I serve that HLS stream using nodejs builtin http-server

  


  ID3 tag generation

  


  Then I emit some ID3 tags using the following commands :

  


  id3taggenerator -title foo -artist bar -a localhost:50000
id3taggenerator -text "foo bar" -d "sample text" -r -a localhost:50000


  


  Reading

  


  Now to read out the tags I use this little SwiftUI app :

  


  import SwiftUI
import AVKit

let bipbopUrl = URL(string: "https://devstreaming-cdn.apple.com/videos/streaming/examples/bipbop_16x9/bipbop_16x9_variant.m3u8")!
let localUrl = URL(string: "http://damiaantheopro14.local:8081/prog_index.m3u8")!
let local = AVPlayerItem(url: localUrl)
let bipbop = AVPlayerItem(url: bipbopUrl)

struct ContentView: View {
    let player = AVPlayer()
    let observer = Id3Observer()
    var lastTag: AVMetadataGroup?
    
    var body: some View {
        VStack {
            HStack {
                Button("BipBop") {
                    player.replaceCurrentItem(with: bipbop)
                    bipbop.add(observer.metadataOutput)
                }
                Button("Local") {
                    player.replaceCurrentItem(with: local)
                    local.add(observer.metadataOutput)
                }
                Button("🅧") {
                    player.replaceCurrentItem(with: nil)
                }
            }
            VideoPlayer(player: player)
        }
        .padding()
    }
}

class Id3Observer: NSObject, AVPlayerItemMetadataOutputPushDelegate {
    let metadataOutput = AVPlayerItemMetadataOutput()
    
    override init() {
        super.init()
        metadataOutput.setDelegate(self, queue: .global())
    }
    
    func metadataOutput(_ output: AVPlayerItemMetadataOutput, didOutputTimedMetadataGroups groups: [AVTimedMetadataGroup], from: AVPlayerItemTrack?) {
        print("metadataOutput", groups.count)
        print("\t", groups.map { group in
            group.items.map { item in
                "\(item.dataType) \(item.keySpace!) \(item.key!) \(item.time.seconds) \(item.duration.seconds.rounded())"
            }.joined(separator: "/n/t")
        }.joined(separator: "\n\t"))
    }
}