Size of Converted MKV is larger than the original TS file

[richt 94]

First comment to make here is that I haven't changed my settings.  Files being converted today using the same parameters are producing MKV files that are just slightly larger than the source TS file.  I can't point to an event when this changed, but my "gut feeling" is that it changed after a recent update to Emby server.  Previously conversions produced files about 25% the size of the original.  

 

If something has changed, I'm not aware of it, so any pointers you can give will be appreciated.  Let me know if you need any more information.  Log attached.

 

ffmpeg-transcode-40972723-88aa-4fbe-b77b-84aa60338ae4_1.zip

[Luke 42085]

Hi there, what quality have you chosen for the conversion?

[richt 94]

Hi Luke,

My conversions are set for TV, original quality, and the H264 encoding CRF is set to 21.

[Luke 42085]

As a test, can you try turning off hardware accelerated transcoding in server transcoding settings? Let's see how the software encoder compares. thanks.

[richt 94]

Hi Luke,

I turned off hardware encoding and the resulting file was in line with the file size I was expecting, a little less than half the size of the original.  I turned on AVC in hardware encoding and got a corrupt file.  Not sure if that was a fluke so I will re-run that transcode.  

[richt 94]

After multiple hardware encodes it seems that hardware encoding is broken for me.  Converted files are corrupt AVC or HEVC.  A 1 hour 2 minutes file after converting is 1 hour 30 minutes and has trouble playing.  I'll look at video drivers and such, but something is definitely wrong.

[Luke 42085]

@richt Are you still having an issue with this?

[Carlo 4561]

On 11/26/2019 at 10:58 PM, richt said:

Hi Luke,

My conversions are set for TV, original quality, and the H264 encoding CRF is set to 21.

Do you need CRF that low?  23 is more typical for HD content with 27 being ideal for bluray type content.

[richt 94]

I have pretty much disabled all conversions as I couldn't fond a solution at the time.  I'll retest.

One of my main purposes for conversion was to change the container from a Silicondust generated "ts" file to an mkv file as well as save a little space.  

@cayars - Changing the CRF value didn't seem to significantly impact the file size.  These were conversions of recorded TV shows (not bluray).  

[Carlo 4561]

Question for you.  What tuner are you using?

Have you looked to see what codecs are inside the TS recording file?

I ask this because for me with a Prime on Comcast they use H.264 on most of my channels especially HD ones and MPEG2 on some of the SD channels.

So if I try to convert them the SD files will shrink because of mpeg2 being changed to h.264 which has much better compression BUT if I try to convert the HD channels already in H.264 I'm not achieving anything and can get bigger files.

So try taking a look at the video codec and see if it's h.264 vs mpeg2 being used.  If h.264 a simple remux (or leave it a lone) is preferred.