[theora-dev] File size comparisons

salsaman salsaman at gmail.com
Mon Oct 18 07:54:03 PDT 2010

OK, good points all of you. Like I said it was a very briefly done comparison.



On Mon, Oct 18, 2010 at 11:04 AM, Jonathan Harker <jon at jon.geek.nz> wrote:
> On 18/10/10 13:26, salsaman wrote:
>> Hi all,
>> I just did a brief test with 3 different codec combinations:
>> 1) ffmpeg sorenson/flv, mp3 audio in flv container
>> 2) ffmpeg h264/vorbis audio/matroska
>> 3) ogg/theora/vorbis using encoder_example
>> Here are the results:
>> 10721201 2010-10-16 14:46 origem1.flv
>> 20731108 2010-09-13 23:04 origem1.mkv
>> 33101703 2010-10-03 11:24 origem1.ogv
>> as you can see, flv wins hands down, and it doesn't look too good for .ogv :-(
> Unfortunately this is completely meaningless, for many reasons.
> 1. Your test includes several independent and uncontrolled variables -
> you are simultaneously comparing container format, video format, audio
> format, audio codec and file size.
> 2. What source material did you use? At the very least, what was the
> duration of the source material? What resolution was the source
> material? Did you resize it and if so what resolution did you resize it to?
> 3. There is no indication what quality settings for the video or the
> audio codecs you are using, therefore we have no way to know whether the
> filesize difference is because (for example) your MP3 audio was at 64
> kbps and the vorbis was at 128 kbps.
> 4. It's not entirely clear what you are comparing, or even how. Are you
> are comparing file container formats (i.e. the Ogg container), or video
> format (i.e. Theora)? You seem to be just going by file size, which
> isn't going to tell you much at all, especially if you are trying to
> compare quality.
> If you're comparing video quality then I suggest you keep the audio and
> container constant (i.e. use the Matroska container since that will
> encode Flash video, H.264 and Theora), and use the same audio stream (or
> leave it out altogether). Then make sure your video clips output the
> same bitrate. This will probably require tweaking if using
> VBR/ABR/constant rate factor etc. H.264 has many knobs which if you turn
> up to 11 should produce the best result but at the expense of CPU
> decoding. However Theora can now produce video better than MPEG4 Part 2
> (DivX et al.) and at least the same and probably better than baseline H.264:
> http://people.xiph.org/~greg/video/ytcompare/comparison.html
> http://people.xiph.org/~maikmerten/youtube/
> I'm certain other list members could chime in with even better
> comparisons! :-)
> J
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