what is the right bitrate for youtube?

[marcorocchini]

Hi ****

I'm encoding a video for youtube with ffmpeg at costant bitrate of 15.280k

is it ok for youtube?

thanks

[newpball]

That depends entirely on the codec, framerate and resolution of the video.

But constant bitrate is just wrong as you have no physical size constraints.

[_Al_]

For youtube (and not only) use constant quality settings where you keep desired uploaded quality throughout of picture. Constant bitrate is not optimal, nor economical, you could waste bitrate at a moment and with some scenes you might not have enough bitrate. Encode H.264 using ffmpeg, use x264 and set desired CRF , perhaps start with 18.

As long as you start thinking CRF (understand CRF = encoding to pretty much constant quality perceived by human) you can disregard, frame rate, resolution etc. or thinking about bitrates. CRF would tell you what bitrate is desired for you particular video.

Perhaps with lower resolutions you can lower CRF a step or so. Lower CRF means better quality, it is kind of unintuitive. Zero would mean lossless.

[marcorocchini]

ffmpeg.exe -y -i input.avs -c:v libx264 -profile:v high -level:v 4.1 -pix_fmt yuv420p -g 33 -bf 2 -vf yadif,colormatrix=bt709:bt601 -crf 18 -c:a libmp3lame -b:a 320k -aspect 16:9 youtube1.mp4

but using -crf 18 can I predict the final size of the output? Also I need to store in a 4,7GB Dvd-data

[jagabo]

That depends entirely on the codec, framerate and resolution of the video.

It also depends on the video content. A video with little motion and noise will require very little bitrate. A video with a lot of motion, noise, flickering lights, flickering fire, billowing smoke or fog, etc. will require much more bitrate.

This is why there are "quality" based encoders (crf or qp in x264, Target Quantizer in Xvid, Constant Quantization in HcEnc). You specify the quality you want, the encoder uses whatever bitrate is necessary to deliver that quality. With bitrate based encoding you pick the bitrate and the encoder delivers whatever quality it can for that bitrate.

If you need files of a specific size you use bitrate based encoding. If you want guaranteed quality you use quality based encoding.

[marcorocchini]

I have use -crf 16:

ffmpeg.exe -y -i 26marzo.avs -c:v libx264 -profile:v high -level:v 4.1 -pix_fmt yuv420p -g 33 -bf 2 -vf yadif,colormatrix=bt709:bt601 -crf 16 -c:a libmp3lame -b:a 320k -aspect 16:9 youtubePrimaParteCRF16.mp4

so that 37 minutes of video in HD is 8.2 GB with a bitrate of 29,3 Kbits

Generale
Complete name : J:\sfilataESP\youtubePrimaParteCRF16.mp4
Format : MPEG-4
Format profile : Base Media
Codec ID : isom
File size : 7,72 GiB
Duration : 37min
Overall bit rate : 29,3 Mbps
Writing application : Lavf56.26.101

Video
ID : 1
Format : AVC
Format/Info : Advanced Video Codec
Format profile : High@L4.1
Format settings, CABAC : Si
Format settings, ReFrames : 4 frame
Format settings, GOP : M=3, N=33
Codec ID : avc1
Codec ID/Info : Advanced Video Coding
Duration : 37min
Bit rate : 29,0 Mbps
Width : 1.920 pixel
Height : 1.080 pixel
Display aspect ratio : 16:9
Frame rate mode : Costante
Frame rate : 25,000 fps
Color space : YUV
Chroma subsampling : 4:2:0
Bit depth : 8 bit
Scan type : Progressivo
Bits/(Pixel*Frame) : 0.559
Stream size : 7,64 GiB (99%)
Writing library : x264 core 146 r2538 121396c
Encoding settings : cabac=1 / ref=3 / deblock=1:0:0 / analyse=0x3:0x113 / me=hex / subme=7 / psy=1 / psy_rd=1.00:0.00 / mixed_ref=1 / me_range=16 / chroma_me=1 / trellis=1 / 8x8dct=1 / cqm=0 / deadzone=21,11 / fast_pskip=1 / chroma_qp_offset=-2 / threads=12 / lookahead_threads=2 / sliced_threads=0 / nr=0 / decimate=1 / interlaced=0 / bluray_compat=0 / constrained_intra=0 / bframes=2 / b_pyramid=2 / b_adapt=1 / b_bias=0 / direct=1 / weightb=1 / open_gop=0 / weightp=2 / keyint=33 / keyint_min=3 / scenecut=40 / intra_refresh=0 / rc_lookahead=33 / rc=crf / mbtree=1 / crf=16.0 / qcomp=0.60 / qpmin=0 / qpmax=69 / qpstep=4 / ip_ratio=1.40 / aq=1:1.00

Audio
ID : 2
Format : MPEG Audio
Format version : Version 1
Format profile : Layer 3
Mode : Joint stereo
Codec ID : 6B
Duration : 37min
Duration_LastFrame : -1ms
Bit rate mode : Costante
Bit rate : 320 Kbps
Channel(s) : 2 canali
Sampling rate : 48,0 KHz
Compression mode : Con perdita
Delay relative to video : 80ms
Stream size : 86,4MiB (1%)
Writing library : LAME3.99.5

I wonder: is correct this type of encoding/bitrate for youtube? thanks

[jagabo]

I have use -crf 16... so that 37 minutes of video in HD is 8.2 GB

And the next 37 minute video you encode may end up 4 GB or 20 GB. It all depends on the content.

Youtube is going to reencode it with the same very low quality no matter what you upload. You probably won't notice any difference between a crf 16 upload and a crf 20 upload once Youtube is done with it. The only difference you'll see is how long the upload takes.

[_Al_]

Any bitrate for Youtube is correct. It is a choice.

The bigger bitrate the better, but there is certain quality level when even increasing bitrate would not help at all because of YouTube's limited bitrate distribution. You just need to find sweet spot for yourself. The other reason is volume, I'd suggest CRF 18 and up, even 20 perhaps or so, not lower, lower values make little sense for YouTube and volume can get insanely bigger as well. For someone to upload , say, 2GB could be no problem, but a nightmare for the other.

So you have to find that sweet spot. CRF 16 and its bitrates would be too much for me for sure.

Using CRF you do not need to encode the whole thing. You can encode most common type in you video, or just something at the begginning and then you can stop encoding , and do basic math what final size would approximately be, just looking at encoder window you can see bitrates right away, not sure if ffmpeg shows that average bitrate like x264 command line does, x264 command line shows average bitrate at all times

[marcorocchini]

but youtube recode at low quality even if I upload in fullHD and with high quality/bitrate?

[poisondeathray]

but youtube recode at low quality even if I upload in fullHD and with high quality/bitrate?

Yes, currently they do

There will be little difference if you upload a lossless version 10x larger

[marcorocchini]

oh my ***

[pandy]

but youtube recode at low quality even if I upload in fullHD and with high quality/bitrate?

Yes, so there is no sense to go for slow compression settings - YT reencode everything. Only one thing can be important for compression settings - your upload speed - if you have poor upload speed then spending a slightly more time for create smaller filesize may have sense but usually upload will be anyway faster.

[marcorocchini]

mm, but cats

I have upload on youtube the attached MP4 using this commanline:

ffmpeg.exe -y -i testSF.wav -i testSF.avi -c:v libx264 -profile:v high -level:v 4.1 -pix_fmt yuv420p -g 33 -bf 2 -vf yadif,colormatrix=bt709:bt601 -crf 16 -c:a libmp3lame -b:a 320k -aspect 16:9 testYTCRF16.mp4

where testSF.avi (wav) is the uncompressed interlaced fullHD output from my NLE

it seems to me that when I upload on youtube, the playback of youtube is a little yerky:

https://www.youtube.com/watch?v=TQPOo6di5Y4

but seems to me that the original testYTCRF16.mp4 is smooth, not jerky

Why in youtube is jerky?

[pandy]

mm, but cats

pussies OK, cats shit NOK

it seems to me that when I upload on youtube, the playback of youtube is a little yerky:

https://www.youtube.com/watch?v=TQPOo6di5Y4

but seems to me that the original testYTCRF16.mp4 is smooth, not jerky

Why in youtube is jerky?

Seems seem to be a good word - download file from YT and play with same video player on computer as source file or even better - stack 2 videos and compare.

[marcorocchini]

because you see it ok on youtube?

[jagabo]

It's very common for youtube videos to play with jerks because Adobe can't figure out how to play videos smoothly.

I downloaded the 720p25 video from youtube and it played smoothly locally (well, as smooth as 25p ever is) but it's jerky in Firefox at youtube.

[pandy]

because you see it ok on youtube?

because i don't trust web browser multimedia functionality and i've downloaded your file from YT and from provided link then watched both.

[marcorocchini]

It's very common for youtube videos to play with jerks because Adobe can't figure out how to play videos smoothly.

oh____