* Claudiu Rad-Lohanel on Monday, February 16, 2015 at 12:31:58 +0200 > On 2/16/2015 10:46 AM, Moritz Barsnick wrote: >> For one, we might identify that your problem has been fixed already. >> Here's a (fixed) ticket concerning a similar matter: >> >> https://trac.ffmpeg.org/ticket/2857 > > No, that didn't fix what Wesley reports. > > I am watching the subject for a quite long time, seen also when that > ticket was closed. I compiled, tested afterwards, the HLS segmenting > overhead seems the same. I've compiled and tested many times since, > the problem is the same. > Maybe actually what we report is a different problem than #2857 with > similar effect so I didn't comment on it without proof. > I wanted to report this but never had the time to gather all the > samples and create a nice report of it. Maybe now I'll be more > motivated if Wesley doesn't do it before me. > > Bottom line: Apple's segmenter introduces low overhead of only a few > precent at low bitrates like 150-200kbit, while ffmpeg may reach > 15-20% no matter what mpegts path you choose. And this is a problem > not only because of such high waste but also as it yields Apple > validation warnings for the HLS stream generated with ffmpeg. > Also the mpegts output is the same for ffmpeg no matter if you > generate .ts directly or use ssegment or whatever, which would make > sense as from what I figured from the source, the muxer used is the > same? Or maybe here I am wrong.. > > And to also clarify something: ffmpeg's overhead is ALWAYS bigger than > Apple's mediafilesegmenter, no matter the bitrate. But I assume it > tends to be more constant (or it grows slower with bitrate), thus, you > don't see such high percentages with higher bitrates. But if you > segment a 1mbit 1GB video with ffmpeg vs. Apple's segmenter, you'll > see tens of MB of difference between them. > It's clearly a general efficiency problem in ffmpeg in HLS case, I > assume that's because Apple squeezed everything it could from mpegts > while ffmpeg uses the generic mpegts muxer which must create valid and > compatible streams for all kinds of devices.
Don't have blind faith in Apple's segmenter though. It seems to overoptimize and may get the duration wrong (and actually quite massively): http://flowplayer.blacktrash.org/fp5/hls-segmenter.html -- \black\trash movie _COWBOY CANOE COMA_ Ein deutscher Western/A German Western --->> http://www.blacktrash.org/underdogma/ccc.php _______________________________________________ ffmpeg-user mailing list ffmpeg-user@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-user