flv to mp4 file conversion too large

Using applications, configuring, problems
Post Reply
Message
Author
User avatar
nubc
Posts: 2062
Joined: Tue 23 Jan 2007, 18:41
Location: USA

flv to mp4 file conversion too large

#1 Post by nubc »

I used an online video file converter to change a 9.85 mb FLV file to MP4. The output converted file seems too large at 16 mb. The mp3 from the same source flv file is only 4.2 mb. As I recall there isn't much difference in size between FLV and MP4 file formats. In this instance, I expect an output MP4 of about 12 mb, with no loss in audio or video quality. Any recommendations on how to make this file conversion. Thanks

r__hughes
Posts: 359
Joined: Thu 13 Apr 2006, 04:14
Location: Montreal, Canada

#2 Post by r__hughes »

I am using a 32bit version of puppy slacko5.7 which has ffmpeg built in. I can open a terminal in the folder containing the flv file (eg test.flv) & use the command

ffmpeg -i test.flv test.mp4

To convert a flv video to mp4 format

There is no significant change in quality & the mp4 filesize is generally the same or smaller. Good Luck
--- quad booting Slacko57NPAE, Slacko56NPAE, Slacko55PAE (with OO4, devx, Gimp) & WXP on DELL Dimension 2400 PC & DELL Latitude 630 Laptop using grub.
---USB-Flash booting same on Samsung N110 WXP Netbook and Lenovo q100 WXP netPC.

User avatar
nubc
Posts: 2062
Joined: Tue 23 Jan 2007, 18:41
Location: USA

#3 Post by nubc »

Results using ffmpeg commandline conversion
output mp4 = 7.01 mb
mp3 extracted (online converter) from output mp4 = 4297 kb
Last edited by nubc on Mon 28 May 2018, 02:17, edited 1 time in total.

User avatar
nubc
Posts: 2062
Joined: Tue 23 Jan 2007, 18:41
Location: USA

#4 Post by nubc »

Just out of curiosity, what is the ffmpeg command to convert from flv/mp4 to mp3?
Extract Audio

ffmpeg -i video.mp4 -f mp3 -ab 192000 -vn music.mp3

The -i option in the above command is simple: it is the path to the input file. The second option -f mp3 tells ffmpeg that the ouput is in mp3 format. The third option i.e -ab 192000 tells ffmpeg that we want the output to be encoded at 192Kbps and -vn tells ffmpeg that we dont want video. The last param is the name of the output file.
https://gist.github.com/protrolium/e0dbd4bb0f1a396fcb55

Seems a bit complicated. BTW the music video is 4m35s in length, and contains 3 or 4 static images.

User avatar
nubc
Posts: 2062
Joined: Tue 23 Jan 2007, 18:41
Location: USA

#5 Post by nubc »

output mp3 with 192k bitrate parameter = 6447kb
output mp3 without bitrate parameter = 4297kb @ 128k bitrate

User avatar
nic007
Posts: 3408
Joined: Sun 13 Nov 2011, 12:31
Location: Cradle of Humankind

Re: flv to mp4 file conversion too large

#6 Post by nic007 »

nubc wrote:I used an online video file converter to change a 9.85 mb FLV file to MP4. The output converted file seems too large at 16 mb. The mp3 from the same source flv file is only 4.2 mb. As I recall there isn't much difference in size between FLV and MP4 file formats. In this instance, I expect an output MP4 of about 12 mb, with no loss in audio or video quality. Any recommendations on how to make this file conversion. Thanks
It depends on your conversion settings. BTW - There will ALWAYS be a loss in quality if you convert the source file to another file format. I use VLC to convert my videos.

User avatar
nic007
Posts: 3408
Joined: Sun 13 Nov 2011, 12:31
Location: Cradle of Humankind

#7 Post by nic007 »

In converting the video part of a video, three things are important, ie. The resolution of the source video, the bitrate and the frame rate. For good quality conversion to mp4 the following settings almost always produce good video: resolution same as source video, bitrate of 1500kb/s, frame rate of 25f/ps.

As far as the sound part goes - Best results can be obtained by keeping the original track as is. Eg: If the sound part of the source video is mp3, 128kb/s then keep it that way. Converting the latter example to 192kb/s won't improve the quality (in fact you will be decreasing quality because you are re-encoding). If it's difficult to obtain the actual bitrate of the source sound file, encoding at 192kb/s is a good choice.

User avatar
Makoto
Posts: 1665
Joined: Fri 04 Sep 2009, 01:30
Location: Out wandering... maybe.

Re: flv to mp4 file conversion too large

#8 Post by Makoto »

nic007 wrote:BTW - There will ALWAYS be a loss in quality if you convert the source file to another file format.
Only if you're re-encoding using lossy codecs, since bits are thrown out during the conversion. If you're re-encoding to a lossless codec (FLAC, etc.), not so much.

You can also sometimes take the streams from within the video container and repackage them in a different-format container as-is, without re-encoding (and therefore, no loss in quality during the 'conversion'). For example, the original FLV could probably work, repackaged as an MKV.
[ Puppy 4.3.1 JP, Frugal install ] * [ XenialPup 7.5, Frugal install ] * [XenialPup 64 7.5, Frugal install] * [ 4GB RAM | 512MB swap ]
In memory of our beloved American Eskimo puppy (1995-2010) and black Lab puppy (1997-2011).

User avatar
nic007
Posts: 3408
Joined: Sun 13 Nov 2011, 12:31
Location: Cradle of Humankind

Re: flv to mp4 file conversion too large

#9 Post by nic007 »

Makoto wrote:
nic007 wrote:BTW - There will ALWAYS be a loss in quality if you convert the source file to another file format.
Only if you're re-encoding using lossy codecs, since bits are thrown out during the conversion. If you're re-encoding to a lossless codec (FLAC, etc.), not so much.

You can also sometimes take the streams from within the video container and repackage them in a different-format container as-is, without re-encoding (and therefore, no loss in quality during the 'conversion'). For example, the original FLV could probably work, repackaged as an MKV.
But lossless "encoding" is not really encoding but a sort of file compression technique, like zip

User avatar
Makoto
Posts: 1665
Joined: Fri 04 Sep 2009, 01:30
Location: Out wandering... maybe.

#10 Post by Makoto »

You still have to encode the proper headers/flags/metadata/etc. for the output track format. :)
[ Puppy 4.3.1 JP, Frugal install ] * [ XenialPup 7.5, Frugal install ] * [XenialPup 64 7.5, Frugal install] * [ 4GB RAM | 512MB swap ]
In memory of our beloved American Eskimo puppy (1995-2010) and black Lab puppy (1997-2011).

Post Reply