[aklug] Re: Converting ogv to mp4

Hmm... It's nice to know I'm not the only one seeing a larger file
size. I still don't know why it's larger. I guess that's the way it is.

Sent from my iPhone

On Apr 25, 2010, at 4:29 PM, Jim Gribbin <jimgribbin@gmail.com> wrote:

> I occasionally watch the videos available on Linux Journal's
> Website. I
> was just watching one that appears to be a recording of some desktop
> operations and I noticed that it is available to download in either
> ogv
> or mp4.
>
> The ogv is 16.4 MB, the mp4 is 49.5 MB. I won't go so far as to claim
> the guys are the last word on the subject, but ...
>
> http://www.linuxjournal.com/video/working-suse-studio
>
> Also doesn't answer the question of "Why?", and I sure don't know.
>
> Jim G
>
> On Tue, 2010-04-20 at 22:02 -0800, Shane Spencer wrote:
>> It depends on how the frames were set up. For a screencast
>> theora/h.264/mpeg/flv/gif will work pretty well if you assume you
>> need
>> very few intermediate frames. Since you used a screen recorder
>> chances are the theora stream was encoded with that in mind.
>> Converting it may have introduced more full frames.
>>
>> I'm guessing media delivery is done using using TCP for the final
>> stream.. Try converting it with ffmpeg and control how often full
>> frame updates are made.
>>
>> Also, you may end up tricking the other codec and causing a larger
>> output by not smoothing the original input to remove the visual
>> boundary on all motion blocks. This is important if you're encoding
>> to a "natural" codec like h.264 since it would really really like to
>> not have to encode straight lines left behind from one block size
>> into
>> a stream that uses a different block size. If the original source
>> looks fine then this may not be the case.. but I've seen some
>> transcoding from low bitrate mpeg4 to other formats get larger in
>> some
>> areas of the stream due to this.
>>
>> - Shane
>>
>> On Tue, Apr 20, 2010 at 10:22 AM, damien hull
>> <damien@linuxninjas.tv> wrote=
>> :
>>> I'm trying to do a screen cast. I used record my desktop to
>>> capture the s=
>> creencast. That saves it in ogv format. That's the open source ogg
>> theora f=
>> ormat. The file size was something like 160 megabytes or something
>> like tha=
>> t. I used the video editor kdenlive to convert the video into an
>> h264 encod=
>> ed mp4 video file at 8000k. I think that 800k is the bit rate.
>> Anyway, the =
>> file size was something like 240 megabytes.
>>>
>>> Why is the mp4 video file larger then the ogv file? Shouldn't it
>>> be going=
>> down in size? I must be missing something here.
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Received on Tue Apr 27 08:13:07 2010