Bug 355340

Summary:	Audio/video timeline playback stutter
Product:	[Applications] kdenlive	Reporter:	qubodup
Component:	Rendering & Export	Assignee:	Jean-Baptiste Mardelle <jb>
Status:	RESOLVED NOT A BUG
Severity:	normal	CC:	stasnel
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Compiled Sources
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:	15.12.0
Sentry Crash Report:

Description qubodup 2015-11-14 15:58:52 UTC

catalyst-hook 15.9-6
catalyst-libgl 15.9-2
catalyst-utils 15.9-2
kdenlive-git 15.09.0.r6532.f08cc46-1
mlt-git r4132.v0.9.2.354.g4f22f28-1
movit 1.2.0-1
pulseaudio 7.1-1
pulseaudio-alsa 2-3
pulseaudio-gconf 7.1-1

When playing back audio/video in the timeline, re-positioning the play head often causes stuttering.

This happens both with SDL and RtAudio while PulseAudio is turned on.

Video: https://youtu.be/mlpsExRhC68

Note: If I try running Kdenlive with Pulseaudio killed and pasuspender, it will freeze as soon as I try to play back audio (or I'm too impatient to wait). I would have to test this more though before making a ticket.

Comment 1 qubodup 2015-11-14 16:03:42 UTC

PS: Steps to reproduce:

1. Start Kdenlive
2. Download #14 from http://librivox.org/the-universal-declaration-of-human-rights-by-the-united-nations/ and drag it into project bin
3. From project bin, drag the clip into the timeline
4. Play back the timeline
5. Use the mouse to jump around the timeline

Expected Result:
1. When clicking in the timeline one of the following happens
a) playback continues instantly from the position to which you jump
b) playback continues where it was before the click, until the computer is ready to play back from the position where you clicked. Then it starts playing back from where you clicked.
c) playback stops and starts again, as soon as the computer is ready to play back from the clicked position

Actual result:
1. Kdenlive starts playing back from the clicked position, however often it jumps back to that position after a fraction of a second, sometimes once, sometimes up to 3 times.


Computer specs:
Distro        4.1.13-1-lts x86_64
Mainboard     FOXCONN A7GM-S 2.0
CPU           AMD Phenom(tm) 9550 Quad-Core Processor
              4 x 2200 MHz, 64-bit
RAM           7.8G
Video         Advanced Micro Devices, Inc. [AMD/ATI]
              Cape Verde PRO [Radeon HD 7750/8740 / R7 250E]
OpenGL        4.4.13399 Core Profile Context 15.20.1013, GLSL 4.40
GCC           gcc (GCC) 5.2.0

Comment 2 qubodup 2015-11-22 05:09:45 UTC

I believe this might have been a problem with PulseAudio and not at all Kdenlive. I had similar problems with Audacity and mplayer but hadn't noticed because mplayer only would stutter at the beginning of playback and I hadn't used Audacity in a while. The solution was one of the following two (I applied both, didn't test which one fixed it -shame on me):
https://wiki.archlinux.org/index.php/PulseAudio/Troubleshooting#Laggy_sound
https://wiki.archlinux.org/index.php/PulseAudio/Troubleshooting#Choppy.2Fdistorted_sound