[FFmpeg-user] Lossless cut from a h264 video with audio

[Samat Galimov]

exactly same result as 'cook-start', i.e.

/usr/bin/env ffmpeg -y -ss 0:03:18 -t 0:00:10 -i cook.mp4 -c copy cook-start.mp4 &> cook-start.txt; # ss input option


> On 10 Oct 2018, at 19:30, DopeLabs <dopelabs at dubstep.fm> wrote:
> 
> try this one...
> 
> 
> /usr/bin/env ffmpeg -y -ss 0:03:18  -i cook.mp4 -t 0:00:10 -c copy cook-start.mp4 &> cook-start.txt
> 
> 
> 
>> On Oct 10, 2018, at 8:44 56AM, Samat Galimov <s at samat.me <mailto:s at samat.me>> wrote:
>> 
>> Hello,
>> 
>> tl;dr: Q: is there a way to cut a 10 second clip from a h264 video (downloaded from youtube) to later use it in web browsers with no quality loss?
>> 
>> What I have tried so far: http://alpha.rawg.io/question/
>> 
>> Long version:
>> 
>> My inputs are http://alpha.rawg.io/question/cook.txt <http://alpha.rawg.io/question/cook.txt><http://alpha.rawg.io/question/cook.txt <http://alpha.rawg.io/question/cook.txt>>
>> 
>> My first attempt is to opt-in for copy codecs using the following command:
>> 
>> 	/usr/bin/env ffmpeg -y -ss 0:03:18 -t 0:00:10 -i cook.mp4 -c copy cook-start.mp4 &> cook-start.txt
>> 
>> What I've got is:
>> - Safari: audio/video sync is OK, beginning is OK, but additional 3 seconds of audio without video in the end
>> - Chrome: audio/video is out of sync
>> 
>> Then I tried to specify -ss as an output option:
>> 
>> 	/usr/bin/env ffmpeg -y -i cook.mp4 -ss 0:03:18 -t 0:00:10 -c copy cook-end.mp4 &> cook-end.txt
>> 
>> Safari & Chrome: first 3 seconds have no video, but audio only.
>> 
>> 
>> Is there a clever trick to overcome this apparent keyframe location issue while not re-encoding videos? 
>> 
>> If there is no way to avoid re-encoding, what options should I use to minimise quality loss?
>> 
>> Here is the webpage to check out my results & source files: https://alpha.rawg.io/question/ <https://alpha.rawg.io/question/><https://alpha.rawg.io/question/ <https://alpha.rawg.io/question/>>
>> 
>> Thank you very much in advance.
>> 
>> Samat.
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