[mythtv-users] anyone h.264 transcoding? want to share your magic?

[Roger Heflin]

On fedora 20 I am using this, though I am not cutting the resolution
to sd, I have reduced the quality quite a bit.    The crf= adjusts
quality, higher is worse quality.    Given my eyes and the distance
from the TV 30 is producing acceptable quality.   Without size
reduction I get between a 5x and 10x reduction in file size.

/usr/bin/ffmpeg -i ${filename} -threads ${threadcnt} -async 3000
-acodec ac3 -aq 33 -ab 320k -vcodec libx264 -x264opts crf=30
${filename}.${fm}

The only issue I have had is that I lose audio when ffmpegs hits a bad
drop in the recording, but that does not happen that often on the
strong channels.   Other that that issue mythtv has played everything
transcoded back correctly.

Also remember to do this after transcoding:

/usr/bin/mythcommflag --rebuild -f ${filename}

Otherwise the seeking has issues.

On Sun, Feb 15, 2015 at 7:37 PM, Brian J. Murrell <brian at interlinx.bc.ca> wrote:
> On Sun, 2015-02-15 at 17:35 -0500, Peter Bennett (cats22) wrote:
>>
>> I believe handbrake is the best option. I have encoded hundreds of
>> recordings this way. Get the latest version from ppa
>> ppa:stebbins/handbrake-releases
>>
>>     HandBrakeCLI  -i "$input" -o "$output" -f mkv -e x264 --x264-preset
>> faster --x264-profile high --x264-tune film  \
>>         -q 21  -E lame --ac 2 --ab 128 \
>>           -l 480 -X 852 \
>>         --decomb
>
> Hrm.  Even using HandBrake I still get a file that only plays now for 10
> minutes.  Here's my HB command line:
>
> HandBrakeCLI -i /storage2/3093_20150215155900.mpg -o /storage2/3093_20150215155900.mkv -f mkv -e x264 --x264-preset faster --x264-profile high --x264-tune film -q 21 -E copy --decomb --crop 60:60:0:0 -w 720 -l 360
>
> And when done, I rebuild the seektable:
>
> $ mythcommflag -v all --loglevel debug --nologserver --rebuild --file /storage2/3093_20150215155900.mkv
> 2015-02-15 20:32:26.923610 C  mythcommflag version: fixes/0.27 [v0.27.4-4-gb305eb5] www.mythtv.org
> 2015-02-15 20:32:26.923641 C  Qt version: compile: 4.8.1, runtime: 4.8.1
> MythTV Commercial Flagger, building seek table for:
>     The West Block
> Rebuild started at Sun Feb 15 20:32:27 2015
> No I-frames found, rewinding...
> 2015-02-15 20:32:27.738431 E  [matroska,webm @ 0x1ece600] File is broken, keyframes not correctly marked!
> Rebuild completed at Sun Feb 15 20:33:37 2015
> 2015-02-15 20:33:37.316427 E  decoding error
>                         eno: Unknown error 541478725 (541478725)
>
> And when I play in mythavtest it now thinks this 30 minute file is only
> 10 minutes log when Mplayer is perfectly capable of playing the full 30
> minutes long.
>
> b.
>
>
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