[FFmpeg-user] Help with transcoding a vid from 1280x720 to highest quality HD 1920x1080

jd1008 jd1008 at gmail.com
Mon Mar 21 18:57:13 CET 2016



On 03/21/2016 09:51 AM, Moritz Barsnick wrote:
> On Sun, Mar 20, 2016 at 11:36:17 -0600, jd1008 wrote:
>
>> highest quality HD 1920x1080
> You should know better by now to be more specific. E.g. do you have any
> restriction when it comes to codec? Time to convert? File size?
>
> The best quality with the smallest effort can indeed be achieved if you
> let the player/client rescale. I know that some rescalers are bad (I
> own at least one :-P), so you may have a reason.
>
> Rescaling on source level implies reencoding. "Highest quality" can
> strictly only be achieved if you re-encode to a lossless codec (or
> codec variant), at the cost of large files/large bandwidth. does your
> client even understand lossless codecs? Are you okay with large
> bandwidth????
>
> Even if "lossy" is okay, to achieve similar quality (despite no
> information being added when upscaling), you need more bandwidth than
> the original. You will have to experiment what fits your need.
>
> All those caveats aside:
> $ ffmpeg -i EarthView.mp4 -vf scale=hd1080 -c:v libx264 -c:a copy EarthView.large.mp4
>
> If the quality is not sufficient, add "-crf NN" as output (codec)
> option, and choose a smaller number for NN than the default 23.
>
> I could give better advice if I knew what you were aiming for...
>
> Moritz
Thank you Moritz.

Using the command you provided.
So far, it has transcoded this much:
frame=45418 fps=6.8 q=28.0 size=  640737kB time=00:31:34.44 
bitrate=2770.7kbits/s

I tried to play the partialy transcoded file (not sure if that is the 
right thing to do),
and I got just a lot of changing colored tiny squares and numerous 
messages of:

[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=65
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=65
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=94
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=66
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=68
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=81
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=65
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=65
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=67
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=66
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=91
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=65
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=74
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=64
[dvvideo @ 0x7fdfee20ff20]AC EOB marker is absent pos=101

PS: Using ffmpeg-2.6.8-1.fc22.x86_64


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