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最近在仔细研究SUNIV家族（F1C100S）在裸机/RTOS上实现H264硬件解码的可行性。我会尽量在这里保留一些参考资料，并开始分享资源。

我对全志车手的理解如下。

VE
负责低层操作。主要由一个由VE引擎中断驱动的状态机组成，它使用两个定时器和一个任务列表。
我认为这个内核可以运行裸机（至少对于 PoC 而言），它没有什么特别之处。要与 RTOS 一起使用，只需实现互斥体包装器。我用直接函数替换了 ioctl。几个小时后，我能够将这部分集成到裸机 MDK 项目中，只需稍加努力，它应该可以正常工作。
这个核心是3个文件，cedar_ve_sl.c cedar_ve.h和list.h（linux双向链表实现）。
我使用了这些源代码： https://github.com/mirkerson/c600/tree/master/linux-3.10/drivers/media/cedar-ve

ve.zip

CedarX
负责所有数据处理，由各种块、FB、VB、vdecoder + plugins、OMX组成。
由于大量异步操作，这自然取决于互斥锁，但是，可能可以使用调度程序或其他技巧在裸机中运行它。
经过几个小时的工作，项目编译没有错误。必须修改各种东西。 RTOS 依赖包在 osal.c 中。 pixelformat.c 已经扩展了需要 ARMCC 6 的 inline asm，所以请注意 MDK 编译器版本。
我使用了这些来源： https://github.com/allwinner-zh/media-codec/tree/master/sunxi-cedarx/SOURCE

cedarx.zip

allwinner的一篇关于LibVE架构的论文和其他一些文档
https://github.com/linux-sunxi/cedarx-libs/blob/master/doc/Libve%20User%20Guide-2011.7.6.pdf

这里是 MELIS 的 CEDAR 模块的非编译版本：
https://github.com/caochunjie45/test/tree/master/eMod/mod_cedar
遗憾的是，这仍然依赖于其他编译库，因此它不包含编写 h264 驱动程序所需的所有源代码，但它仍然很有帮助。

当然，如果我们能找到一个旧 MELIS 的完整来源，或者只是 H264 驱动程序的来源（也许一些前 Alwinner 员工可以帮助提供一个旧的 H264 PoC？或一个旧驱动程序？）可以随时自己尝试，总是很有趣。

稍加清理后，我将添加 MDK 项目

Recently, i have studied closely the feasability of implementing the H264 hardware decoding on bare metal / RTOS for the SUNIV familly (F1C100S). I will try to keep some references here, and start to share ressources.

My understanding of the allwinner driver is as follow.

VE
in charge of low level operations. Mainly consists of a state machine driven by the VE engine interrupt, it uses two timers and a tasklist.
I think this core can run bare metal (at least for PoC), there is nothing special about it. To use with RTOS only the mutexes wrapper have to be implemented. I replaced ioctl by direct functions. After few hours i was able to integrate this part into the bare metal MDK project, with few more efforts it should work OK.
This core is 3 files, cedar_ve_sl.c cedar_ve.h and list.h (linux doubly linked list implementation).
i used these source source: https://github.com/mirkerson/c600/tree/master/linux-3.10/drivers/media/cedar-ve

ve.zip

CedarX
in charge of all data handling, composed of various blocks, FB, VB, vdecoder + plugins, OMX.
Naturally this depends on mutexes due to numerous async operation, however, it is probably possible to run it in bare metal with scheduler or other trick.
After wfew hours of work the project compiles without error. Various things had to be modified. RTOS dependencies are wrapped in osal.c.  pixelformat.c has extended inline asm which requires ARMCC 6, so pay attention to the MDK compiler version.
I used these source : https://github.com/allwinner-zh/media-codec/tree/master/sunxi-cedarx/SOURCE

cedarx.zip

A paper from allwinner about the architecture of LibVE and few other documents
https://github.com/linux-sunxi/cedarx-libs/blob/master/doc/Libve%20User%20Guide-2011.7.6.pdf

A non compiled version of CEDAR module of MELIS here:
https://github.com/caochunjie45/test/tree/master/eMod/mod_cedar
Sadly this still relies on other compiled libraries, so it does not contain all the sources required to write the h264 driver, but it is helpful nontheless.

Of course, it would be great if we can find the full sources of an old MELIS, or just the sources of H264 driver (maybe some former Alwinner employee can help to give an old H264 PoC? or an old driver?), anyway we can always try by ourselves, it is always interesting.

I will add the MDK projects after a little bit of cleaning

最近编辑记录 hoel (2021-09-20 00:05:51)