[FFmpeg-user] the trim filter

[Mark Filipak]

On 05/07/2024 07.54, Paul B Mahol wrote:
> On Fri, Jul 5, 2024 at 2:09 AM Mark Filipak <markfilipak.imdb at gmail.com>
> wrote:
> 
>> On 04/07/2024 17.12, Paul B Mahol wrote:
>>> Its in documentation: asetpts=N/SR/TB, assuming everything starts from 0,
>>> so add it after each atrim.
>>
>> For both video & audio,
>>     time_base=1/90000
>>     start_pts=1048560
>>
>> So, there are 'silent' audio samples starting with the first video frame.
>> I'm dropping 20.062
>> seconds of video (i.e., 481 frames). I really don't know how I could
>> rewrite audio PTSes to make
>> that 20.062 seconds of audio to go away. I really think that's impossible.
>> They have to be dropped,
>> just as I am dropping the 481 video frames.
>>
>> Here's my trim commands for the first segment:
>>
>>
>> trim=start_frame=481:end_frame=134047,atrim=start_sample=962962:end_sample=268360093
>>
>> Here's the interesting terminal output (slightly beautified):
>>
>> [Parsed_trim_1 @ 0000000000620040]
>>    Media type mismatch between the 'Parsed_trim_1' filter output pad 0
>> (video) and the
>> 'Parsed_atrim_2' filter input pad 0 (audio)
>>
>> [AVFilterGraph @ 000000000061c7c0] Error linking filters
>>
>> Failed to set value
>>    'split=2[i5][i6],
>>    [i5]trim=start_frame=481:end_frame=134047,
>> atrim=start_sample=962962:end_sample=268360092[o5],
>>    [i6]trim=start_frame=138745:end_frame=246719[o6],
>>    [o5][o6]concat=n=2'
>> for option 'filter_complex': Invalid argument
>> Error parsing global options: Invalid argument
>>
> 
> This is exact proof that your FFmpeg CLI skills are bellow flat absolute
> zero. I'm wasting my and everyone else time replying to your questions.

What do you see, Paul, that is wrong? I respect you and your knowledge, but because you cite no 
evidence, it reduces what you write to the level of opinion. Well, anyone can have an opinion, eh? 
If there are 100 opinions, then at least 99 of them are wrong, and perhaps all 100 are wrong.

I've given up trying to cut on IDR-frames because I don't know how to find which frames are 
IDR-frames and FFmpeg is not helping with that task. So, I'm decoding video & audio to pictures & 
samples and doing the trimming in those decoded domains. An error statement like "Failed to set 
value" tells me nothing. So, I come here...

ffmpeg-user is intended to help users to succeed with FFmpeg. Well, trimming and splicing is 
important, wouldn't you say? So, what's wrong with my -filter_complex?

--Mark.