<div dir="ltr">This is all a huge pain! So thanks so much Eric! Sounds like you have a good plan.<div><br></div><div>-CHB</div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Aug 15, 2016 at 11:27 AM, Eric Firing <span dir="ltr"><<a href="mailto:efiring@hawaii.edu" target="_blank">efiring@hawaii.edu</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">It's all incredibly confusing, as the wikipedia article shows. The first problem is the distinction between the container format and the codec; both have to be recognized and handled properly by an application. The file extension generally is more indicative of the container than the codec.<br>
<br>
MPEG-4 seems to be an umbrella that can cover a wide variety actual codecs, one of which is h264, and that at least implies a file format ("version 2").<br>
<br>
Specifying the mpeg4 codec in animation, with avconv or ffmpeg, seems to result in the use of a codec "mpeg4 (Simple Profile)"--but I suspect this might depend on how avconv or ffmpeg was built. Specifying h264 results in use of the newer and more efficient h264 encoder, which is what I am proposing to make the default.<br>
<br>
One problem: h264 (at least as implemented in ffmpeg and avconv) can't handle frame dimensions that include an odd number of pixels, but mpeg4 can. Regardless of whether h264 is the default, we should trap this error at an early stage; otherwise it leads to a non-obvious failure mode.<br>
<br>
I need to do a little more testing before submitting any PR. I want to identify the conditions that were leading to video files that were completely corrupted. When I was trying to get things working I was not keeping track of what I was doing, so I need to backtrack and make a set of examples.<br>
<br>
Eric<span class=""><br>
<br>
On 2016/08/15 7:38 AM, Benjamin Root wrote:<br>
</span><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex"><span class="">
As I stated in my book:<br>
<br>
"While I will not claim to possess anything more than a passing<br>
familiarity with movie formats, I recognize that neither do many other<br>
people. For those who have had experience editing and creating movies<br>
and understand these concepts far more extensively, you can skip this<br>
section; be assured that I could not possibly add any new knowledge. For<br>
those reading on, there are likely to be some over-simplifications. As<br>
such, this section is only intended to provide enough information to<br>
successfully render animations and avoid pitfalls and should not be<br>
considered authoritative."<br>
<br>
My quick research at the time found that while mpeg4 and h.264 weren't<br>
strictly equivalent, for all intents and purposes they could be<br>
considered as such. And it is my understanding that avconv and such were<br>
treating it as the same (unless explicitly told not to). If I am wrong<br>
in this regard, please refer to the previous paragraph and kindly file<br>
an errata for my book.<br>
<br>
Cheers!<br>
Ben Root<br>
<br>
<br>
On Mon, Aug 15, 2016 at 1:23 PM, Chris Barker <<a href="mailto:chris.barker@noaa.gov" target="_blank">chris.barker@noaa.gov</a><br></span><span class="">
<mailto:<a href="mailto:chris.barker@noaa.gov" target="_blank">chris.barker@noaa.gov</a>><wbr>> wrote:<br>
<br>
<br>
<br>
On Mon, Aug 15, 2016 at 6:21 AM, Benjamin Root <<a href="mailto:ben.v.root@gmail.com" target="_blank">ben.v.root@gmail.com</a><br></span><span class="">
<mailto:<a href="mailto:ben.v.root@gmail.com" target="_blank">ben.v.root@gmail.com</a>>> wrote:<br>
<br>
In my research for the animation chapter of my book, I also came<br>
to the conclusion that the `mpeg4` codec in a .mp4 container was<br>
the best bet for out-of-the-box compatibility across platforms.<br>
<br>
<br>
Ben -- is that H.264? It seem "mpeg 4" is not well defined. from<br>
Wikipedia:<br>
<br>
<br>
<br>
"MPEG-4 is still an evolving standard and is divided into a number<br>
of parts. Companies promoting MPEG-4 compatibility do not always<br>
clearly state which "part" level compatibility they are referring to."<br>
<br>
Sigh.<br>
<br>
<br>
<br>
The one place where that format didn't work was MS PowerPoint<br>
on Windows (but, oddly enough, it worked on PowerPoint on MacOSX).<br>
<br>
<br>
That's because PPT punts to the "system" for decoding -- it has<br>
little if any built-in support. A freakin' nightmare.<br>
<br>
<br>
Note, I did that test a couple of years ago on a Windows 7<br>
machine, so I don't know if that limitation is still valid.<br>
<br>
<br>
I think H.264 is getting better and better supported.<br>
<br>
Question: how is MPL planning to support it? Is there a<br>
not-too-hard-to-install cross platform lib???<br>
<br>
-CHB<br>
<br>
<br>
<br>
--<br>
<br>
Christopher Barker, Ph.D.<br>
Oceanographer<br>
<br>
Emergency Response Division<br></span>
NOAA/NOS/OR&R <a href="tel:%28206%29%20526-6959" value="+12065266959" target="_blank">(206) 526-6959</a> <tel:%28206%29%20526-6959><br>
voice<br>
7600 Sand Point Way NE <a href="tel:%28206%29%20526-6329" value="+12065266329" target="_blank">(206) 526-6329</a> <tel:%28206%29%20526-6329> fax<br>
Seattle, WA 98115 <a href="tel:%28206%29%20526-6317" value="+12065266317" target="_blank">(206) 526-6317</a> <tel:%28206%29%20526-6317><br>
main reception<br>
<br>
<a href="mailto:Chris.Barker@noaa.gov" target="_blank">Chris.Barker@noaa.gov</a> <mailto:<a href="mailto:Chris.Barker@noaa.gov" target="_blank">Chris.Barker@noaa.gov</a>><span class=""><br>
<br>
<br>
<br>
<br>
______________________________<wbr>_________________<br>
Matplotlib-devel mailing list<br>
<a href="mailto:Matplotlib-devel@python.org" target="_blank">Matplotlib-devel@python.org</a><br>
<a href="https://mail.python.org/mailman/listinfo/matplotlib-devel" rel="noreferrer" target="_blank">https://mail.python.org/mailma<wbr>n/listinfo/matplotlib-devel</a><br>
<br>
</span></blockquote><div class="HOEnZb"><div class="h5">
<br>
______________________________<wbr>_________________<br>
Matplotlib-devel mailing list<br>
<a href="mailto:Matplotlib-devel@python.org" target="_blank">Matplotlib-devel@python.org</a><br>
<a href="https://mail.python.org/mailman/listinfo/matplotlib-devel" rel="noreferrer" target="_blank">https://mail.python.org/mailma<wbr>n/listinfo/matplotlib-devel</a><br>
</div></div></blockquote></div><br><br clear="all"><div><br></div>-- <br><div class="gmail_signature" data-smartmail="gmail_signature"><br>Christopher Barker, Ph.D.<br>Oceanographer<br><br>Emergency Response Division<br>NOAA/NOS/OR&R (206) 526-6959 voice<br>7600 Sand Point Way NE (206) 526-6329 fax<br>Seattle, WA 98115 (206) 526-6317 main reception<br><br><a href="mailto:Chris.Barker@noaa.gov" target="_blank">Chris.Barker@noaa.gov</a></div>
</div>