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@ddennedy
Last active July 27, 2022 03:44
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Use ffmpeg and mp4box to prepare DASH-AVC/264 v1.0 VoD
See my DASH-IF presentation from October, 2014:
https://s3.amazonaws.com/misc.meltymedia/dash-if-reveal/index.html#/
1. encode multiple bitrates with keyframe alignment:
ffmpeg -i ~/Movies/5D2_Portrait.MOV -s 1280x720 -c:v libx264 -b:v 1450k -bf 2 \
-g 90 -sc_threshold 0 -c:a aac -strict experimental -b:a 96k -ar 32000 out.mp4
My input was 30 fps = 3000 ms. If it were 29.97, then a GOP size of 90 frames will yield a base segment
size of 3003 milliseconds. You can make the segment size some multiple of this, e.g.: 6006, 9009, 12012.
You could encode to other resolutions and bitrates here, and if you do, you might want to skip the audio
encoding for them. To do that replace "-c:a aac -strict experimental -b:a 96k -ar 32000" with "-an".
2. verify keyframes:
ffprobe -show_frames -print_format compact out.mp4 | less
=> too difficult to read
ffprobe -show_frames -print_format compact out.mp4 |
awk -F '|' '($2 == "media_type=video") {print i++, $3}' | less
=> Now we can just see video key frame indication - better, but let's filter it more.
ffprobe -show_frames -print_format compact out.mp4 |
awk -F '|' '($2 == "media_type=video") {if ($3 == "key_frame=1") print i, $3; ++i}'
=> Now we can just see frame# of frames that are a key frame and verify they are multiples of 90.
At this point, we could extend the awk with a test on i modulo 90 and exit with result
code 1 to signal failure in an automated script.
3. segment and generate mpd:
mp4box -dash 3000 -rap -profile dashavc264:onDemand out.mp4#audio out.mp4#video
=> generates out_dash.mp4 and out_track?_dashinit.mp4
If you have multiple files at different bitrates, just add them to the end of the command
line, but there will be more _track_dashinit.mp4 files you need to ensure you upload.
4. test locally:
Osmo4 out_dash.mpd
5. view mp4 dump:
mp4box -diso -stdb out_track1_dashinit.mp4 2>&1 | xmllint -format -
or, mp4dump out_track1_dashinit.mp4
6. upload to web server:
s3cmd put --acl-public out_dash.mpd out_track?_dashinit.mp4 s3://${S3BUCKET}/dash/
7. validate mpd:
http://dashif.org/conformance.html
copy-and-paste: http://${S3BUCKET}.s3.amazonaws.com/dash/out_dash.mpd
8. play with dashif.org test player:
http://dashif.org/reference/players/javascript/1.0.0/index.html?mpd=http://${S3BUCKET}.s3.amazonaws.com/dash/out_dash.mpd
9. embed in own web page using video.js and dash.js:
s3cmd put --acl-public --recursive videojs-dash/* s3://${S3BUCKET}/videojs/
open http://${S3BUCKET}.s3.amazonaws.com/dash/videojs.html
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8" />
<title>Video.js DASH-AVC/264</title>
<!-- Video.JS -->
<link href="/videojs/video-js.css" rel="stylesheet">
<script src="/videojs/video.dev.js"></script>
<!-- Dash.JS -->
<script src="https://rawgit.com/Dash-Industry-Forum/dash.js/master/dash.min.js"></script>
<!-- Video.JS Tech Loads -->
<!-- videojs-dashjs -->
<!-- <script src="https://rawgit.com/Dash-Industry-Forum/dash.js/master/contrib/videojs/videojs-tech-dashjs.js"></script> -->
<script src="/videojs/videojs-tech-dashjs.js"></script>
</head>
<body>
<video id="vid1" class="video-js vjs-default-skin" data-setup='{}'
width="854" height="480" controls preload="auto">
<source src="/dash/out_dash.mpd" type="application/dash+xml">
</video>
</body>
</html>
@dphov
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dphov commented Sep 22, 2017

@ddennedy FYI:
https://trac.ffmpeg.org/wiki/Encode/AAC#NativeFFmpegAACencoder

Note: -strict experimental (or -strict -2) was previously required for this encoder, but it is ​no longer experimental and these options are unnecessary since 5 December 2015.

@Anmolk22
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Does this approach generate muxed or demuxed streams for audio and video

@samelie
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samelie commented Jan 21, 2019

@Anmolk22 muxed

@azhar5678
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i want to know , if 1gb mpd dash taking 12 sec to play after forward or rewind , how to reduce the time.

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