Reduce File Size fast and quality ok for stream

[tomasrage]

Hello guys, now I'm facing another situation, I have this file about 2.5Gb

Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2mp41
encoder : Lavf56.36.100
Duration: 00:54:37.67, start: 0.000000, bitrate: 5725 kb/s
Stream #0:0(und): Video: mpeg4 (Advanced Simple Profile) (mp4v / 0x7634706D), yuv420p, 1666x940 [SAR 1:1 DAR 833:470], 5592 kb/s, 18.67 fps, 18.67 tbr, 18666 tbn, 20 tbc (default)
Metadata:
handler_name : VideoHandler
Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 48000 Hz, stereo, fltp, 127 kb/s (default)
Metadata:
handler_name : SoundHandler


I need to filesize max of 650mb
I need to do it fast because I have to convert about 45 files
I need quality 480p or 720p

Any way to do it?
Thanks in advance

[jagabo]

Something like:

ffmpeg -y -i source.mkv -vf scale=w=-4:h=480 -codec:v libx264 -preset veryfast -b 1100k -acodec copy output.mkv

That took about 7.5 minutes on my i5 2600K.

[tomasrage]

thank you!!

[jagabo]

You can convert all the files in a folder with a batch file:

for %%F in (*.mp4) do (
    ffmpeg -y -i "%%F" -vf scale=w=-4:h=480 -codec:v libx264 -preset veryfast -b 1100k -acodec copy "%%~dpnF.new.mp4"
)

Put that batch file in the same folder as a bunch of MP4 files and double click on it. All the files will be reencoded to 1100 kbps.

veryfast doesn't provide the best quality. Try a slower preset if you can bare the longer encoding times. Other presets for x264:

ultrafast
superfast
veryfast
faster
fast
medium
slow
slower
veryslow
placebo

For example, the slow preset will get you better image quality but will take about 3 times longer.

[tomasrage]

Jagabo, thank you for your help, the quality of this convertion is very poor, video show like slow motion and the camera transition is very notorius, so, I have to check with the slow preset. I have another question, maybe is not in this trend, I have some files in .ts I need to convert to .mp4 and I don't care the filesize, just need the same quality, I dont know if ffmpeg works on this kind of files or if I have to try another software, I have ubuntu server and only know about ffmpeg and mkvmatroska.
Thank you four your help and time !

[jagabo]

Jagabo, thank you for your help, the quality of this convertion is very poor, video show like slow motion and the camera transition is very notorius, so, I have to check with the slow preset.

Something isn't working right. Switching to the slow preset probably won't make much of a difference. Can you make one of your sources available so I can test it?

I have another question, maybe is not in this trend, I have some files in .ts I need to convert to .mp4 and I don't care the filesize, just need the same quality, I dont know if ffmpeg works on this kind of files or if I have to try another software, I have ubuntu server and only know about ffmpeg and mkvmatroska.
Thank you four your help and time !

If the codecs are suitable for the MP4 container you can use ffmpeg to simply remux.

ffmpeg -i "input.ts" -vcodec copy -acodec copy "output.mp4"

or with aac audio:

ffmpeg -i "input.ts" -vcodec copy -acodec copy -absf aac_adtstoasc "output.mp4"

Remuxing will not change the quality of the video or audio.

If you need to reencode the video:

ffmpeg -y -i input.mkv -vcodec libx264 -preset slow -crf 18 -acodec copy output.mp4

The combination of preset slwo and crf 18 is pretty transparent at normal playback speed. But if you find it's not good enough use a lower CRF value -- that will give you higher quality and a bigger file. Around crf 12 you can hardly see a difference even with A/B switching still frames and using a magnifier. Conversely, if you find the result is too big and can live with lesser quality you can use a higher crf value.