[FFmpeg-user] Can I speed up transcoding?

Reindl Harald h.reindl at thelounge.net
Tue Jan 8 18:24:54 CET 2013

Am 08.01.2013 18:17, schrieb Dan M:
> On 01/08/2013 11:00 AM, Reindl Harald wrote:
>> Am 08.01.2013 17:57, schrieb Leo Papadopoulos:
>>> Reindl:
>>> A bit more info from Adobe's manuals:
>>> To note, at this
>>> time Flash Player cannot encode audio to the AAC or MP3 standards, which
>>> are required if you want to stream audio to iOS devices using HTTP Live
>>> Streaming (HLS).
>> what the hell - why should flash ENCODE the files?
>> or in other words: if you use ffmpeg to ENCODE why the hell
>> have your application to encode it a second time?
> If I'm reading the chain of message correctly, he is using Flash Player to encode his video. Flash Player can
> encode streams using H.264 (AVC1) for video, but doesn't have any iOS compatible audio encoding codecs. Therefore
> he is encoding using Flash Player, then wants to run his stream through ffmpeg to re-encode the audio using AAC.

but why re-encode only the audio instead the whole stream?
do not encode it in the first front to FLV because no origin
material will be FLV and so you will not have additional
encoding for H264 and you can satisfy any client

or live with a bad multihtreading performance because
below the start of this thread

* 1m30s versus 1m39s is normal
  you can not expect permanently the full performance

* "get a faster instance from Amazon EC2" is a completly
  wrong conclusion in the context of "I tried threads up to 16"
  and FLV as target codec

> I ran tests using ultrafast about 20 times
> and the transcode time for my 1m39s FLV vary from 0m28s to 1m30s. This
> shows that the Amazon instance I am using is giving me variable performance
> depending on what else is going on in the virtual cloud.
> My conclusion is that I will need to get a faster instance from Amazon EC2.

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