[FFmpeg-user] Converting numerous files to h264

[neoculture23]

First of all, many thank to all who have been helping me. After reading the
various pages I have had pointed to me, I have made my command line thus:

ffmpeg -i "filename.ext" \
    -vprofile high \
    -preset veryslow \
    -map 0 \
    -threads 0 \
    -c:a copy -c:s copy -c:d copy -c:t copy \
    -c:v libx264 \
    -crf 23 \
    "filename.mkv"

And I'm probably repeating myself with some of these parameters...

I am now playing with the CRF value, and tried a few between 22-24. Here
are the results in terms of sizes:

Original: 288,270,774
Default:  210,738,125 (ffmpeg defaults, no parameters, 73% of original file
size)
crf22:     214,530,280 (Above command line, crf of 22, 74%)
crf23:     193,136,555 (67%)
crf24:     173,912,796 (60%)

Original: 250,068,560
Default:  187,402,004 (75%)
crf22:     190,052,807 (76%)
crf23:     172,670,535 (69%)
crf24:     156,883,580 (63%)

So depending on the crf, I can get a file down to 60-74% of its original
size... which would save me quite a lot of room over all of my rips.

But which crf to use? 22, 23 or 24? I don't think I want to go much outside
that range; do people have any experience about which value they have used
successfully over a large number of video files?





On 12 November 2012 06:36, Boštjan Strojan <bostjan.strojan at gmail.com>wrote:

> On Sun, Nov 11, 2012 at 8:59 PM, Dielson Sales
> <dielsonscarvalho at gmail.com> wrote:
> > I would follow this guide[1] and choose a crf value instead of defining a
> > bitrate, hence
> > you can think of quality instead of bitrate. If I'm not mistaken,
> choosing
> > a fixed bitrate
> > value can lead to different results depending on the input
> characteristics,
> > such as
> > resolution, am I right?
> >
> >
> > [1] http://ffmpeg.org/trac/ffmpeg/wiki/x264EncodingGuide
>
> Absolutely, crf is the way to go.
>