Conversion

[Delafuentedelfuego 3]

Hi,

 

I realize that my conversions in Emby (really very practical) do not take into account the choice of the selected bitrate.  When I select convert to --> MKW --> HEVC --> "Custom" quality and enter a value (eg 3) it converts everything to 2Mbs and not 3 as selected.  In addition, I specify that the source always has a higher bitrate (between 5 and 10 in H264).
 
 Can you help me or explain to me?
 
 
 Thank you in advance for your immense work!

[Luke 42078]

Hi, what makes you think it doesn’t take into account the selected bitrate?

[Delafuentedelfuego 3]

Hi, Library display.

I chose a 3Mbs file and ended up with 2 everywhere.

[Luke 42078]

Can you provide an example conversion log?

How to Report a Problem

When you select a quality, you're really setting the upper limit, not an exact value.

[Delafuentedelfuego 3]

Oky,

 

Thanks for the reply.

I will now increase my value!

For this example I selected 4Mbs and now I also have everything at 2....

 

[Luke 42078]

Can you provide an example conversion log?

[Delafuentedelfuego 3]

20:28:11.926   Stream #0:0: Video: hevc (Main), cuda(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 2000 kb/s, 23.98 fps,

[Delafuentedelfuego 3]

ffmpeg-transcode-c934b491-2376-48fa-a98a-1d9514f7c7d6_1.txt

[Delafuentedelfuego 3]

Conversion finished but still the same result.

ffmpeg-transcode-fa78abfe-bdd4-4611-a3de-122b52c5bf7c_1.txt

[Delafuentedelfuego 3]

21:16:57.388   Stream #0:0: Video: h264 (High), cuda(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 4940 kb/s, 23.98 fps,

[Delafuentedelfuego 3]

Hi, I tried to try again but this time with the following parameters:
 
 Custom-MKW-HEVC-Bitrate original quality.
 
 The video was in 4K H264, bitrate 14Mbs.
 
 The result is also attached as well as the conversion log
 
 4K HEVC HDR10 Bitrate 3Mbs.
 
 I specify that I had selected identical quality.  I'm new to video but it seems strange to me to go from 14Mbs to 3 for 4K (light).

ffmpeg-transcode-f7160be5-379a-4eec-a061-a91f2ffdc2f6_1.txt

[Luke 42078]

On 2/9/2024 at 3:22 PM, Delafuentedelfuego said:

21:16:57.388   Stream #0:0: Video: h264 (High), cuda(tv, bt709, progressive), 1920x1080 [SAR 1:1 DAR 16:9], q=2-31, 4940 kb/s, 23.98 fps,

The value you selected is the total bitrate for the whole file.

Your screenshot is only showing 2 mbps for the video stream, but there must be audio inside that file?  Possibly even subtitles. All of those things have bitrates.

Does this answer your question?

[Luke 42078]

20 hours ago, Delafuentedelfuego said:

Hi, I tried to try again but this time with the following parameters:
 
 Custom-MKW-HEVC-Bitrate original quality.
 
 The video was in 4K H264, bitrate 14Mbs.
 
 The result is also attached as well as the conversion log
 
 4K HEVC HDR10 Bitrate 3Mbs.
 
 I specify that I had selected identical quality.  I'm new to video but it seems strange to me to go from 14Mbs to 3 for 4K (light).

ffmpeg-transcode-f7160be5-379a-4eec-a061-a91f2ffdc2f6_1.txt 599.54 kB · 0 downloads

Because going from h264 to hevc, you can achieve the same quality with a lower bitrate. Does this answer that question?

[Delafuentedelfuego 3]

Hi Luke,   

Thank you for your answer.   I didn't understand whether the selected bitrate (2,4,8) was respected.  If you tell me that everything is Normal then that suits me perfectly!

[Luke 42078]

Right these look OK to me. We'll look at improving the conversion dialog user interface to make more clear the expected result. Thanks.

[Delafuentedelfuego 3]

Hi Luc,
 

I have a new question. Would it be possible to keep the DTS audio format when converting to HEVC?

Thanks in advance for your help!

[Luke 42078]

On 2/19/2024 at 4:53 AM, Delafuentedelfuego said:

Hi Luc,
 

I have a new question. Would it be possible to keep the DTS audio format when converting to HEVC?

Thanks in advance for your help!

There currently isn't an option for that because the goal of the conversion feature is to try and maximize direct playing across devices...but it's certainly something that could be added.

[Delafuentedelfuego 3]

Hi Luc,I'm reviving the topic because I have a new question.
 
 Would it be possible to convert the media to HEVC while keeping the same quality?

 For example :
 
 A 14.7 GB film encoded in H264 with a bit rate of 12 mbs.

 When converting to HEVC using the server, select the same quality of the file and compress it to 3 mbs and is now only 3.4 GB.
 When playing on Firefox, the server must decode the video (which is normal) in H264 but in 6 mbs,
 
 In my opinion, if the file had been encoded in identical quality, I should have 10 or 12 mbs in H264 and 5 or 6 in HEVC.
 
 Furthermore, selecting a quality manually (8, 10, 20 Mbs) changes absolutely nothing to the final file (HEVC 3.4 GB with 3 mbs).
 
 Should we abandon this way of doing things to optimize the library?  Do you have to go through an external program (Handbrack).  The big advantage is the ease of use and the possibility of automatically converting the chosen files!
 
 Thank you for your help and available for any additional questions.

[Neminem 1519]

If you decide to go with a external program.

Check out Tdarr 

[Luke 42078]

@DelafuentedelfuegoCan we please look at a specific example of this:

Quote

When converting to HEVC using the server, select the same quality of the file and compress it to 3 mbs and is now only 3.4 GB.

Thanks !

[Delafuentedelfuego 3]

Here's the detail!

ffmpeg-transcode-fc3db6fd-17d8-4850-b5a2-e46fa5c084cf_1.txt

[Delafuentedelfuego 3]

Here is what I find on the internet. The H265 format allows you to reduce the file size by about 50%. That's why I was surprised by the result (see logs) of starting with 12mbs in H264 and ending up with 3mbs in HEVC...

[rbjtech 5284]

There is an entire lifetime's worth of reading about codecs and compression on the internet - forums such as doom9.org etc are dedicated to it - but ultimately whenever you reduce the original bitrate - you lose quality in the conversion.  Whether that is perceiveable by your eyes or your equipment reproduction (or others), it cannot be 'answered' on any forum.

The only advice I would give before you go on a large 'conversion' journey - is to not accept that one setting fits all - it simply doesn't.     What is acceptable at 3Mbit/sec on one movie, may look very poor (no detail etc) on another - so while there are many batch tools out there - REVIEW the results.

Edited March 6, 2024 by rbjtech

[Delafuentedelfuego 3]

Hello,

Thank you for your reply.

Unfortunately, I agree with you that it is not possible to have a single universal setting and that each media should be treated separately. I am simply wondering about the conversion options available on Emby.

There are "same quality" (which reduces everything to 3 Mbps), "8 Mbps" (which does not change anything compared to the first mode), and then "4 Mbps", "2 Mbps" or "Custom". When I specify 20 Mbps, the file always ends up at 3 Mbps. Hence my question!

[pwhodges 2012]

24 minutes ago, rbjtech said:

 whenever you reduce the original bitrate - you lose quality in the conversion. 

This cannot be emphasised too much.  The loss may be negligible, at least for some people, but it is always there.

On the matter of the bit rate required by different codecs for "equivalent" quality (there are various definitions of this), the figures such as h265 requiring only half of h264 for the same quality are, I think, based on each being encoded from the same greatly superior (or even lossless) source - transcoding from one to the other is not an equivalent operation, because of the quality loss already baked in from the first encoding.

Paul