[FFmpeg-user] Is there a way to speed up to make partial transcoding of a video file.

[shirish शिरीष]

Dear all,

Thank you for making the awesome software ffmpeg.

I am not subscribed to the archives so please CC me in case somebody
answers it one way or the other.

I usually find it takes quite some time when trying to partially
trancode/copy a file.  I am concerned with the startup time. It takes
anywhere between 3-5 minutes before transcoding/copying starts.

Something like https://paste.debian.net/1059975/

I find it takes quite a bit of time for the copy to be there. Is there
anyway to make the process a bit faster, some sort of flag or
something ?

I am asking due to the cpu capabilities given -

[libx264 @ 0x55ab4aa24380] using cpu capabilities: MMX2 SSE2Fast SSSE3
SSE4.2 AVX FMA3 BMI2 AVX2

There might be some more things which could help perhaps -

from inxi -

CPU:       Topology: Quad Core model: Intel Core i5-7400 bits: 64
type: MCP arch: Kaby Lake rev: 9 L1 cache: 256 KiB
           L2 cache: 6144 KiB L3 cache: 6144 KiB bogomips: 24000
           Speed: 800 MHz min/max: 800/3300 MHz Core speeds (MHz): 1:
800 2: 800 3: 800 4: 800
           Flags: 3dnowprefetch abm acpi adx aes aperfmperf apic arat
arch_perfmon art avx avx2 bmi1 bmi2 bts clflush clflushopt cmov
constant_tsc cpuid cpuid_fault cx16 cx8 de ds_cpl dtes64 dtherm dts
ept ept_ad erms est f16c flexpriority flush_l1d fma fpu fsgsbase fxsr
ht hwp hwp_act_window hwp_epp hwp_notify ibpb ibrs ida intel_pt
invpcid invpcid_single lahf_lm lm mca mce mmx monitor movbe mpx msr
mtrr nonstop_tsc nopl nx pae pat pbe pcid pclmulqdq pdcm pdpe1gb pebs
pge pln pni popcnt pse pse36 pti pts rdrand rdseed rdtscp rep_good
sdbg sep smap smep ss ssbd sse sse2 sse4_1 sse4_2 ssse3 stibp syscall
tm tm2 tpr_shadow tsc tsc_adjust tsc_deadline_timer tsc_known_freq vme
vmx vnmi vpid x2apic xgetbv1 xsave xsavec xsaveopt xsaves xtopology
xtpr

Graphics:  Device-1: Intel HD Graphics 630 vendor: ASUSTeK driver:
i915 v: kernel bus ID: 00:02.0 chip ID: 8086:5912
           Display: server: X.Org 1.20.3 driver: modesetting unloaded:
fbdev,vesa resolution: 1600x900~60Hz
           OpenGL: renderer: Mesa DRI Intel HD Graphics 630 (Kaby Lake
GT2) v: 4.5 Mesa 18.2.8 compat-v: 3.0
           direct render: Yes

It's a desktop machine having 8 GB RAM.

Look forward to know if any hack or something can be done to make it a
bit faster, or if there are any settings I can experiment with.

-- 
          Regards,
          Shirish Agarwal  शिरीष अग्रवाल
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