High file size output with AVC to MPEG4 video

TechiMan

Active Member
I've been using a program called Video to Video (Media Converters) on and off for a while, it's not the best video conversion program but it seems to do a decent-ish job with converting various video formats. However, I've been converting some HD AVC files to MPEG-4 and some reason the outputted file is almost twice the size of the original file, even when the quality has been lowered. I did notice that the video bitrate in the defaulted settings is 11000, which is very strange as I think even the standard bitrate of HD is about 8000kbps, so why the program is set to 11000kbps for I don't know. I converted a batch of AVC files which were 1.06GB in total, and the outputted file in MPEG4 was nearly 4GB. How can a compressed file be larger than the original?.

Seems to be a very strange program I'm using.
 

EndlessWaves

Distinguished Member
All video files are compressed.

So you're not talking an uncompressed file and compressing it. You're actually decompressing an existing file and recompressing it using different settings or in a different compression scheme.

H.264 (aka AVC) is one of the two video formats included in the MPEG4 standard, so are you talking about the other one ASP (aka DivX)?

Or do you mean the MPEG4 media file container format (.MP4), which can hold video in various compression types as well as all of the associated data like audio (itself subject to different compression schemes).

H.264 achieves one of the highest ratios of video quality to file size, with only a few newer compression options being better (HEVC and VP9 would be the most common two) so it's entirely possible what you're compressing to is just less efficient.

Or as you say it could be a higher bitrate than the source file which would be fairly pointless, although it also wouldn't explain why you're seeing a quality drop unless you're using a much worse type of compression.
 

TechiMan

Active Member
All video files are compressed.

So you're not talking an uncompressed file and compressing it. You're actually decompressing an existing file and recompressing it using different settings or in a different compression scheme.

H.264 (aka AVC) is one of the two video formats included in the MPEG4 standard, so are you talking about the other one ASP (aka DivX)?

Or do you mean the MPEG4 media file container format (.MP4), which can hold video in various compression types as well as all of the associated data like audio (itself subject to different compression schemes).

H.264 achieves one of the highest ratios of video quality to file size, with only a few newer compression options being better (HEVC and VP9 would be the most common two) so it's entirely possible what you're compressing to is just less efficient.

Or as you say it could be a higher bitrate than the source file which would be fairly pointless, although it also wouldn't explain why you're seeing a quality drop unless you're using a much worse type of compression.
I'm not really familiar with video compression formats.

I know that I have been using Windows Movie Maker over the past week or so convert both MPEG4 and AVC files from my camcorder and digital still camera. I have just finished converting some video files (a mix of MP4 and MOV files) which were in dated folders. My intention was to convert them into MP4 using Movie Maker's standard MPEG4 video setting to my computer so that I could convert them to a DVD. The original files in the folder were 3.95gb in total, yet when I converted the files in Movie Maker the outputted size was 6.45gb, so double the original total file size. Why is that it should be less not more, and some of the videos were trimmed. In Movie Maker there is no settings to adjust it's just choose which video format and then click convert, no messing about with bitrates or anything like that. Something isn't right there.
 

EndlessWaves

Distinguished Member
The original files in the folder were 3.95gb in total, yet when I converted the files in Movie Maker the outputted size was 6.45gb, so double the original total file size. Why is that it should be less not more

A higher bitrate than the original or a format that doesn't compress as much would be the most likely explanations, but without the details I couldn't.

If you're using a preset intended for DVD use them it may well use the older MPEG2 format for the video in an MPEG4 file, which is less efficient than H.264 (aka AVC) and will take up more space for the same quality.

Bit rate is just how much space the file takes up per second of video so it's not an absolute measure of quality but dependant on the format used.

It doesn't make any sense to keep the same bit rate when converting between formats and conversion programs generally won't try and analyse the quality of the old file and keep it the same. Instead they'll just use a one-size-fits-most default value - or a selection of them on a quality slider.
 

TechiMan

Active Member
I put a 733MB MP4 video file into Nero Recode, clicked on MPEG2 and left the settings at best quality but enabled it to fit to 4.7GB. However, the outputted video was 4.06GB, which seemed OK, but when I dropped the MPEG2 video into Nero Video to convert to a DVD TS file to fit a standard DVD, the video file went right over 4GB to 5GB. Why is it doing that when I recoded it to fit a DVD?. I couldn't tell any difference in quality between that and the original MP4 file, which is odd as there should've been some noticeable compression.

And regarding Handbrake again, but why does it save in M4V format?. It's not a recognised format in Nero and other programs.
 
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