On Thu, Jul 21, 2022 at 1:16 PM Sebastian Fricke <sebastian.fricke@xxxxxxxxxxxxx> wrote: > > Hey Nicolas & Robin, > > Thanks for the feedback. > > On 15.07.2022 11:36, Nicolas Dufresne wrote: > >Le vendredi 15 juillet 2022 à 12:04 +0100, Robin Murphy a écrit : > >> On 2022-07-13 17:24, Sebastian Fricke wrote: > >> > Implement the HEVC codec variation for the RkVDEC driver. Currently only > >> > the RK3399 is supported, but it is possible to enable the RK3288 as it > >> > also supports this codec. > >> > > >> > Based on top of the media tree @ef7fcbbb9eabbe86d2287484bf366dd1821cc6b8 > >> > and the HEVC uABI MR by Benjamin Gaignard. > >> > (https://patchwork.linuxtv.org/project/linux-media/list/?series=8360) > >> > > >> > Tested with the GStreamer V4L2 HEVC plugin: > >> > (https://gitlab.freedesktop.org/gstreamer/gstreamer/-/merge_requests/1079) > >> > > >> > Current Fluster score: > >> > `Ran 131/147 tests successfully in 278.568 secs` > >> > with > >> > `python3 fluster.py run -d GStreamer-H.265-V4L2SL-Gst1.0 -ts JCT-VC-HEVC_V1 -j1` > >> > > >> > failed conformance tests: > >> > - DBLK_D_VIXS_2 (Success on Hantro G2) > >> > - DSLICE_A_HHI_5 (Success on Hantro G2) > >> > - EXT_A_ericsson_4 (Success on Hantro G2) > >> > - PICSIZE_A_Bossen_1 (Hardware limitation) > >> > - PICSIZE_B_Bossen_1 (Hardware limitation) > >> > - PICSIZE_C_Bossen_1 (Hardware limitation) > >> > - PICSIZE_D_Bossen_1 (Hardware limitation) > >> > - PPS_A_qualcomm_7 (Success on Hantro G2) > >> > - SAODBLK_A_MainConcept_4 (Success on Hantro G2) > >> > - SAODBLK_B_MainConcept_4 (Success on Hantro G2) > >> > - SLIST_B_Sony_9 (Success on Hantro G2) > >> > - SLIST_D_Sony_9 (Success on Hantro G2) > >> > - TSUNEQBD_A_MAIN10_Technicolor_2 (Success on Hantro G2) > >> > - VPSSPSPPS_A_MainConcept_1 (Success on Hantro G2) > >> > - WPP_D_ericsson_MAIN10_2 (Fail on Hantro G2) > >> > - WPP_D_ericsson_MAIN_2 (Fail on Hantro G2) > >> > > >> > Not tested with FFMpeg so far. > >> > > >> > Known issues: > >> > - Unable to reliably decode multiple videos concurrently > >> > - The SAODBLK_* tests timeout if the timeout time in fluster is lower than 120 > >> > - Currently the uv_virstride is calculated in a manner that is hardcoded > >> > for the two available formats NV12 and NV15. (@config_registers) > >> > > >> > Notable design decisions: > >> > - I opted for a bitfield to represent the PPS memory blob as it is the > >> > perfect tool for that job. It describes the memory layout with any > >> > additional required documentation, is easy to read and a native language > >> > tool for that job > >> > >> Can I point out how terrible an idea this is? The C language gives > >> virtually zero guarantee about how bitfields are actually represented in > >> memory. Platform ABIs (e.g. [1]) might nail things down a bit more, but > >> different platforms are free to make completely different choices so > >> portability still goes out the window. Even for a single platform, > >> different compilers (or at worst even different version of one compiler) > >> can still make incompatible choices e.g. WRT alignment of packed > >> members. Even if you narrow the scope as far as a specific version of > >> AArch64 GCC, I think this is still totally broken for big-endian. > >> > >> The fact that you've had to use nonsensical types to trick a compiler > >> into meeting your expectations should already be a clue to how fragile > >> this is in general. > >> > >> > - The RPS memory blob is created using a bitmap implementation, which > >> > uses a common Kernel API to avoid reinventing the wheel and to keep the > >> > code clean. > >> > >> Similarly, Linux bitmaps are designed for use as, well, bitmaps. Abusing > >> them as a data interchange format for bit-aligned numerical values is > >> far from "clean" semantically. And I'm pretty sure it's also broken for > >> big-endian. > >> > >> This kind of stuff may be standard practice in embedded development > >> where you're targeting a specific MCU with a specific toolchain, but I > >> don't believe it's suitable for upstream Linux. It would take pretty > >> much the same number of lines to use GENMASK definitions and bitfield.h > >> helpers to pack values into words which can then be written to memory in > >> a guaranteed format and endianness (certainly for the PPS; for the RPS > >> it may well end up a bit longer, but would be self-documenting and > >> certainly more readable than those loops). It mostly just means that for > >> any field which crosses a word boundary you'll end up with 2 definitions > >> and 2 assignments, which is hardly a problem (and in some ways more > >> honest about what's actually going on). > > > >Thanks for the feedback, in multimedia (unlike register programming), we don't > >really consider bitstreams as bitmap or bitfield. What we do really expect is to > >use bit writer helpers (and sometimes a bit reader though we try and avoid the > >second one in the kernel). Its more of less a cursor (a bit position) into a > >memory that advance while writing. A bit writer should help protect against > >overflow too. > > > >When writing lets say a chain of 8 bits from a char, a proper helper is expected > >to be very explicit on the ordering (write_u8_le/be or something better worded). > >I would rather like to see all these blobs written this way personally then > >having a cleared buffer and writing using bit offsets. > > > >Perhaps I may suggest to start with implementing just that inside this driver? > >It isn't very hard, and then the implementation can be reduced later and shared > >later, with whatever exists without deviating from the intent of the existing > >API ? I do believe that having this in linux-media can be useful in the future. > >We will notably need to extend such a helper with multimedia specific coding > >technique (golomb, boolean coding, etc.) for use in stateless encoder drivers. > > I currently design a general bit-writer API to handle the mentioned > issues correctly. I'll post it as part of V2, due to my current workload > this will happen in 3 weeks at the earliest. > I wonder if this is really the correct approach. Introducing a new API and adding HEVC support at the same time, sounds like scope creep to me. How about you first introduce HEVC and then we move to the new API? A generic bit-writer API might really take a long time to get mainlined. Thanks! Ezequiel > > > >Nicolas > > > >> > >> Thanks, > >> Robin. > > Greetings, > Sebastian > > >> > >> [1] > >> https://github.com/ARM-software/abi-aa/blob/main/aapcs64/aapcs64.rst#bit-fields > >> > >> > - I deliberatly opted against the macro solution used in H264, which > >> > declares Macros in mid function and declares the fields of the memory > >> > blob as macros as well. And I would be glad to refactor the H264 code if > >> > desired by the maintainer to use common Kernel APIs and native language > >> > elements. > >> > - The giant static array of cabac values is moved to a separate c file, > >> > I did so because a separate .h file would be incorrect as it doesn't > >> > expose anything of any value for any other file than the rkvdec-hevc.c > >> > file. Other options were: > >> > - Calculating the values instead of storing the results (doesn't seem > >> > to be worth it) > >> > - Supply them via firmware (Adding firmware makes the whole software > >> > way more complicated and the usage of the driver less obvious) > >> > > >> > Ignored Checkpatch warnings (as it fits to the current style of the file): > >> > ``` > >> > WARNING: line length of 162 exceeds 100 columns > >> > #115: FILE: drivers/media/v4l2-core/v4l2-common.c:265: > >> > + { .format = V4L2_PIX_FMT_NV15, .pixel_enc = V4L2_PIXEL_ENC_YUV, .mem_planes = 1, .comp_planes = 2, .bpp = { 5, 5, 0, 0 }, .hdiv = 2, .vdiv = 2, > >> > > >> > ERROR: trailing statements should be on next line > >> > #128: FILE: drivers/media/v4l2-core/v4l2-ioctl.c:1305: > >> > + case V4L2_PIX_FMT_NV15: descr = "10-bit Y/CbCr 4:2:0 (Packed)"; break; > >> > ``` > >> > > >> > v4l2-compliance test: > >> > ``` > >> > Total for rkvdec device /dev/video3: 46, Succeeded: 46, Failed: 0, Warnings: 0 > >> > ``` > >> > > >> > kselftest module run for the bitmap changes: > >> > ``` > >> > $ sudo insmod /usr/lib/modules/5.19.0-rc3-finalseries/kernel/lib/test_bitmap.ko > >> > [ 71.751716] test_bitmap: parselist: 14: input is '0-2047:128/256' OK, Time: 1750 > >> > [ 71.751787] test_bitmap: bitmap_print_to_pagebuf: input is '0-32767 > >> > [ 71.751787] ', Time: 6708 > >> > [ 71.760373] test_bitmap: set_value: 6/6 tests correct > >> > ``` > >> > > >> > Jonas Karlman (2): > >> > media: v4l2: Add NV15 pixel format > >> > media: v4l2-common: Add helpers to calculate bytesperline and > >> > sizeimage > >> > > >> > Sebastian Fricke (4): > >> > bitops: bitmap helper to set variable length values > >> > staging: media: rkvdec: Add valid pixel format check > >> > staging: media: rkvdec: Enable S_CTRL IOCTL > >> > staging: media: rkvdec: Add HEVC backend > >> > > >> > .../media/v4l/pixfmt-yuv-planar.rst | 53 + > >> > drivers/media/v4l2-core/v4l2-common.c | 79 +- > >> > drivers/media/v4l2-core/v4l2-ioctl.c | 1 + > >> > drivers/staging/media/rkvdec/Makefile | 2 +- > >> > drivers/staging/media/rkvdec/TODO | 22 +- > >> > .../staging/media/rkvdec/rkvdec-hevc-data.c | 1844 +++++++++++++++++ > >> > drivers/staging/media/rkvdec/rkvdec-hevc.c | 859 ++++++++ > >> > drivers/staging/media/rkvdec/rkvdec-regs.h | 1 + > >> > drivers/staging/media/rkvdec/rkvdec.c | 182 +- > >> > drivers/staging/media/rkvdec/rkvdec.h | 3 + > >> > include/linux/bitmap.h | 39 + > >> > include/uapi/linux/videodev2.h | 1 + > >> > lib/test_bitmap.c | 47 + > >> > 13 files changed, 3066 insertions(+), 67 deletions(-) > >> > create mode 100644 drivers/staging/media/rkvdec/rkvdec-hevc-data.c > >> > create mode 100644 drivers/staging/media/rkvdec/rkvdec-hevc.c > >> > > >> > >
