[Libav-user] This command take 2 minutes to render. Can it be quicker?

[Vijay Kanta]

I recently added the H264 option. The regular copy "-c:v copy" was already
present before and I got rid of them, because the video wasn't playing in
the HTML5 or JW player. It required the special encoding.

As I said before audio copy didn't really make any difference when it
worked. It's just the h264 which is required and I have to use it.

"-2 -strict"  were options from ffmpeg documentation when I was a noob, and
never got rid of them.

Regards,
~Vijay.



On Wed, Jun 4, 2014 at 6:42 PM, Steve Boyer <steveboyer85 at gmail.com> wrote:

> On Wed, Jun 4, 2014 at 5:32 AM, Vijay Kanta <viju.kantah at gmail.com> wrote:
>
>> Hey guys,
>>
>> I found out it's the H264 encoding that is really screwing up the cpu
>> cycles, and not the audio. @carl, moving it down didn't help, it still says
>> invalid command.
>>
>> I found out that h264 encoding takes up 20 minutes with music and srt
>> combined for a 2 min random video clip.
>>
>
> That isn't surprising. That is why (and entirely my fault for not making
> it clearer) I suggested copying the audio stream as well as copying the the
> video stream (by using -c:v copy) as it already is in an MP4 compatible
> format. I've never messed around with subtitles, part of the reason I was
> asking for a sample mp3, mp4, and srt. What is the purpose of the -2 and
> -strict options? Try removing those and see if you have any better luck. If
> those don't work and are still unwilling to provide a sample, start with
> omitting the subtitle portions to make sure that the streams are being
> copied correctly, and build up from there.
>
> Steve
>
>>
>> On Sat, May 31, 2014 at 1:24 PM, Carl Eugen Hoyos <cehoyos at ag.or.at>
>> wrote:
>>
>>> Vijay Kanta <viju.kantah at ...> writes:
>>>
>>> > ffmpeg -i music/qT0pdDhKxFDnfJHq2.mp3 -c:a copy
>>> > -i video/HKp1ZpHbANT4dmGRC.mp4 -vcodec libx264
>>> > -crf 23 -vf subtitles=subtitles/1718379803.srt
>>> > -preset ultrafast -strict -2
>>> > film/HKp1ZpHbANT4dmGRC.mp4
>>>
>>> Move "-c:a copy" behind the last input file.
>>>
>>> But please note that compared to H264 encoding,
>>> audio encoding should always be fast, so the
>>> speed difference between audio copying and
>>> audio reencoding should be less than using
>>> different x264 presets.
>>>
>>> Carl Eugen
>>>
>>> _______________________________________________
>>> Libav-user mailing list
>>> Libav-user at ffmpeg.org
>>> http://ffmpeg.org/mailman/listinfo/libav-user
>>>
>>
>>
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>
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