Flatpak Linux Player Bug: Playback Speed Failure

Introduction: The Core of the Issue

When using the Kazumi player on Flatpak Linux with version 1.8.8, a significant issue arises: the inability to properly set the playback speed. This bug has a direct and detrimental effect on the player's performance, leading to noticeable lag and a generally poor viewing experience. This is especially true for users with less powerful devices that rely heavily on hardware acceleration.

What specific problems are you experiencing?

The primary symptom of this bug is severe stuttering and lag during playback. While the video may start playing, the experience quickly degrades, indicating that hardware decoding is not functioning as intended. This is a crucial aspect for devices with limited processing power, as they often depend on hardware acceleration to smoothly render video content. When this acceleration fails, the player struggles to keep up, leading to the frustrating lag.

Which operating system are you using?

The operating system in use is Linux. The specifics of the Linux distribution are important for context, as different distributions and their configurations can influence how Flatpak applications behave.

Can you provide the device and version information?

The installation method is Flatpak on Manjaro Linux. This information is critical for pinpointing the source of the issue, as Flatpak provides a containerized environment, and Manjaro, being a rolling-release distribution, can have specific configurations that might contribute to the bug. The specific version of Kazumi (1.8.8) is also key, as it indicates the exact codebase where the problem resides.

(Optional) Related hardware information?

lscpu                                        
架构：                       x86_64
  CPU 运行模式：             32-bit, 64-bit
  Address sizes:             39 bits physical, 48 bits virtual
  字节序：                   Little Endian
CPU:                         4
  在线 CPU 列表：            0-3
厂商 ID：                    GenuineIntel
  型号名称：                 Intel(R) Celeron(R) CPU N3450 @ 1.10GHz
    CPU 系列：               6
    型号：                   92
    每个核的线程数：         1
    每个座的核数：           4
    座：                     1
    步进：                   9
    CPU(s) scaling MHz:      95%
    CPU 最大 MHz：           2200.0000
    CPU 最小 MHz：           800.0000
    BogoMIPS：               2189.00
    标记：                   fpu vme de pse tsc msr pae mce cx8 apic 
                             sep mtrr pge mca cmov pat pse36 clflush 
                             dts acpi mmx fxsr sse sse2 ss ht tm pbe 
                             syscall nx pdpe1gb rdtscp lm constant_ts
                             c art arch_perfmon pebs bts rep_good nop
                             l xtopology tsc_reliable nonstop_tsc cpu
                             id aperfmperf tsc_known_freq pni pclmulq
                             dq dtes64 monitor ds_cpl vmx est tm2 sss
                             e3 sdbg cx16 xtpr pdcm sse4_1 sse4_2 x2a
                             pic movbe popcnt tsc_deadline_timer aes 
                             xsave rdrand lahf_lm 3dnowprefetch cpuid
                             _fault cat_l2 ibrs ibpb stibp tpr_shadow
                              flexpriority ept vpid ept_ad fsgsbase t
                             sc_adjust smep erms mpx rdt_a rdseed sma
                             p clflushopt intel_pt sha_ni xsaveopt xs
                             avec xgetbv1 xsaves dtherm ida arat pln 
                             pts vnmi md_clear arch_capabilities
Virtualization features:     
  虚拟化：                   VT-x
Caches (sum of all):         
  L1d:                       96 KiB (4 instances)
  L1i:                       128 KiB (4 instances)
  L2:                        2 MiB (2 instances)
NUMA:                        
  NUMA 节点：                1
  NUMA 节点0 CPU：           0-3
Vulnerabilities:             
  Gather data sampling:      Not affected
  Indirect target selection: Not affected
  Itlb multihit:             Not affected
  L1tf:                      Not affected
  Mds:                       Not affected
  Meltdown:                  Not affected
  Mmio stale data:           Not affected
  Reg file data sampling:    Vulnerable: No microcode
  Retbleed:                  Not affected
  Spec rstack overflow:      Not affected
  Spec store bypass:        Spectre v1
  Spectre v2:                Mitigation; Retpolines; IBPB conditional
                             ; IBRS_FW; STIBP disabled; RSB filling; 
                             PBRSB-eIBRS Not affected; BHI Not affect
                             ed
  Srbds:                     Not affected
  Tsa:                       Not affected
  Tsx async abort:           Not affected
  Vmscape:                   Not affected

The provided CPU information reveals that the device is running on an Intel Celeron N3450 processor. This is a low-power CPU, common in budget laptops and mini-PCs. It has 4 cores and a base clock speed of 1.10GHz. The reliance on hardware decoding is crucial for this type of processor to provide a smooth playback experience. The lack of hardware acceleration can significantly degrade performance. The information about the CPU's vulnerabilities is also important, as it could potentially interact with the playback issues.

Deep Dive: Analyzing the Logs

Log Information

**2025-11-16 01:50:24.658624** 
设置播放速度失败 LateInitializationError: Field 'danmakuController' has not been initialized. 

The log files are crucial in diagnosing the root cause of the playback problems. The initial error message,