[FFmpeg-user] HLS segment duration for multiple framerate encoding
Yisrael
lushimaps at hotmail.com
Tue Jul 21 19:17:10 CEST 2015
I am trying to encode a video to HLS in multiple bitrates (and,
therefore, according to apple's recommendations, multiple frame rates).
I am doing this on video files (not live streams).
I can get one HLS working fine when I have a single variant, or
multiple variants of the same framerate. But when I have variants of
different framerates, I can't get the segment durations to line up.
For example, here are the first few lines of the m3u8 file of the same video encoded a 15 fps and 30 fps. Note the durations of the first segments have _different_lengths_. Also the TARGETDURATION is different.
#EXT-X-TARGETDURATION:10
#EXTINF:9.023222,
640_0.ts
#EXT-X-TARGETDURATION:9
#EXTINF:9.000000,
960_0.ts
My objective is to make a multi-bitrate (and multi-framerate)
stream that will pass apple's mediastreamvalidator test. I have spent a
few days scouring all the forums, tutorials, mailing lists,
messageboards etc...and I still can't get the streams to have segments
of matching durations when I use a different framerate...and without
that, it won't pass the test.
I have tried different segment options (segment vs. hls),
different keyframes options (-g / -force_key_frames), ffmpeg 2 pass
methods, as well as just using ffmpeg for transcoding and segmenting
with apple's segmenter. Even the apple segmentor is ends up segmenting
the files so the audio cuts off in the middle of each segment...
I'm sure this is something that can be done and is done
regularly - can anyone please enlighten me? (for anyone else reading
this later on, considder this an interesting summary of ways to use
ffmpeg to create an HLS stream.)
So, what am I doing wrong and how do I do it right?
Also, can anyone explain what the differences are between -g / -force_key_frames and between hls / segment - and which one is preferable to use?
====================================================================
ffmpeg version 2.7.1-static http://johnvansickle.com/ffmpeg/ Copyright (c) 2000-2015 the FFmpeg developers
built with gcc 4.9.2 (Debian 4.9.2-21)
configuration: --enable-gpl --enable-version3 --disable-shared
--disable-debug --enable-runtime-cpudetect --enable-libmp3lame
--enable-libx264 --enable-libx265 --enable-libwebp --enable-libspeex
--enable-libvorbis --enable-libvpx --enable-libfreetype
--enable-fontconfig --enable-libxvid --enable-libopencore-amrnb
--enable-libopencore-amrwb --enable-libtheora --enable-libvo-aacenc
--enable-libvo-amrwbenc --enable-gray --enable-libopenjpeg
--enable-libopus --enable-libass --enable-gnutls --enable-libvidstab
--enable-libsoxr --cc=gcc-4.9
libavutil 54. 27.100 / 54. 27.100
libavcodec 56. 41.100 / 56. 41.100
libavformat 56. 36.100 / 56. 36.100
libavdevice 56. 4.100 / 56. 4.100
libavfilter 5. 16.101 / 5. 16.101
libswscale 3. 1.101 / 3. 1.101
libswresample 1. 2.100 / 1. 2.100
libpostproc 53. 3.100 / 53. 3.100
SOURCE:
http://www.caminandes.com/download/01_llama_drama_1080p.zip (from open
movie project - note it is 24 fps - maybe that is the problem?)
Resolution: 1920x1080
FrameRate: 24
Profile: h264 High
TARGET: HLS
VARIANT 1:
Resolution: 480x270
FrameRate: 15
Video Bitrate: 400
Audio Bitrate: 64
Keyframe: 45 frames (3 seconds)
Profile: h264 Baseline, 3.0
Segment Size: 9 seconds
VARIANT 2:
Resolution: 640x360
FrameRate: 30 (yes, I am increasing the bitrate - but trying it with 24 didn't help either)
Video Bitrate: 1200
Audio Bitrate: 96
Keyframe: 90 frames (3 seconds)
Profile: h264 Baseline, 3.1
Segment Size: 9 seconds
VARIANT 3:
Resolution: 960x540
FrameRate: 30
Video Bitrate: 1600
Audio Bitrate: 128
Keyframe: 90 frames (3 seconds)
Profile: h264 Main, 3.1
Segment Size: 9 seconds
Here is a summary of the methods I have tried and some of their
outputs: (I am aware that libfdk_aac is a better codec, but my version
currently doesn't have that compiled in)
0) hls commands, -force_key_frames
----------------------------------
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf
h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2
-acodec aac -r 15 -profile:v baseline -level 3 -b:v 400k -maxrate
428.00k -force_key_frames "expr:gte(t,n_forced*3)" -vf "scale=480:-1"
-hls_list_size 0 -hls_time 9 480_.m3u8
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf
h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2
-acodec aac -r 30 -profile:v baseline -level 3.1 -b:v 1200k -maxrate
1284.00k -force_key_frames "expr:gte(t,n_forced*3)" -vf "scale=640:-1"
-hls_list_size 0 -hls_time 9 640_.m3u8
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf
h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2
-acodec aac -r 30 -profile:v main -level 3.1 -b:v 1568k -maxrate
1677.76k -force_key_frames "expr:gte(t,n_forced*3)" -vf "scale=960:-1"
-hls_list_size 0 -hls_time 9 960_.m3u8
#EXT-X-TARGETDURATION:10
#EXTINF:9.023222,
480_0.ts
#EXT-X-TARGETDURATION:10
#EXTINF:9.023222,
640_0.ts
#EXT-X-TARGETDURATION:9
#EXTINF:9.000000,
960_0.ts
1) hls commands, -g
-------------------
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf h264_mp4toannexb
-flags -global_header -vcodec libx264 -strict -2 -acodec aac -r 15
-profile:v baseline -level 3 -b:v 400k -maxrate 428.00k -g 45 -vf
"scale=480:-1" -hls_list_size 0 -hls_time 9 480_.m3u8
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf
h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2
-acodec aac -r 30 -profile:v baseline -level 3.1 -b:v 1200k -maxrate
1284.00k -g 90 -vf "scale=640:-1" -hls_list_size 0 -hls_time 9 640_.m3u8
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf
h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2
-acodec aac -r 30 -profile:v main -level 3.1 -b:v 1568k -maxrate
1677.76k -g 90 -vf "scale=960:-1" -hls_list_size 0 -hls_time 9 960_.m3u8
#EXT-X-TARGETDURATION:12
#EXTINF:11.156556,
480_0.ts
#EXT-X-TARGETDURATION:12
#EXTINF:11.056556,
640_0.ts
#EXT-X-TARGETDURATION:12
#EXTINF:11.033333,
960_0.ts
2) segment commands, -g
-----------------------
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf
h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2
-acodec aac -r 15 -profile:v baseline -level 3 -b:v 400k -maxrate
428.00k -g 45 -vf "scale=480:-1" -f segment -segment_list 480_.m3u8
-segment_time 9 -segment_list_type m3u8 -segment_list_flags -cache+live
480_%05d.ts
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf
h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2
-acodec aac -r 30 -profile:v baseline -level 3.1 -b:v 1200k -maxrate
1284.00k -g 90 -vf "scale=640:-1" -f segment -segment_list 640_.m3u8
-segment_time 9 -segment_list_type m3u8 640_%05d.ts
./ffmpeg -y -i ../infile.mp4 -pix_fmt yuv420p -vbsf
h264_mp4toannexb -flags -global_header -vcodec libx264 -strict -2
-acodec aac -r 30 -profile:v main -level 3.1 -b:v 1568k -maxrate
1677.76k -g 90 -vf "scale=960:-1" -f segment -segment_list 960_.m3u8
-segment_time 9 -segment_list_type m3u8 960_%05d.ts
#EXT-X-TARGETDURATION:12
#EXTINF:11.156556,
480_00000.ts
#EXT-X-TARGETDURATION:12
#EXTINF:11.056556,
640_00000.ts
#EXT-X-TARGETDURATION:12
#EXTINF:11.100000,
960_00000.ts
3) muti-pass (couldn't get it to work - based on:
https://sonnati.wordpress.com/2012/07/02/ffmpeg-the-swiss-army-knife-of-internet-streaming-part-v/
)
-------------
#FIRST PASS
./ffmpeg -i ../infile.mp4 -pass 1 -an -vcodec libx264 -r 30
-b:v 1200k -bufsize 1200k -keyint_min 60 -g 120 -s 640x360 -f mpegts -y
/dev/null
#SECOND PASS
./ffmpeg -i ../infile.mp4 -pass 2 -an -vcodec libx264 -r 30 -b:v 1200k -bufsize 1200k -keyint_min 60 -g 120 -s 640x360 640_.mp4
#SECOND PASS WITH DIFFERENT FRAME RATE (FAILS)
./ffmpeg -i ../infile.mp4 -pass 2 -an -vcodec libx264 -r 15 -b:v 400k -bufsize 400k -keyint_min 30 -g 60 -s 480x270 480_.mp4
#Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height
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