Some incorrectly decoded H.264 videos #35
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Update - using the recently updated patches from LibreELEC master, including LibreELEC/LibreELEC.tv#4988 I've got a matched kernel API and FFmpeg which decodes all the H.264 videos properly, including the samples here which previously caused problems. |
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Kwiboo
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Jul 29, 2023
[ Upstream commit 2aaa8a1 ] With some IPv6 Ext Hdr (RPL, SRv6, etc.), we can send a packet that has the link-local address as src and dst IP and will be forwarded to an external IP in the IPv6 Ext Hdr. For example, the script below generates a packet whose src IP is the link-local address and dst is updated to 11::. # for f in $(find /proc/sys/net/ -name *seg6_enabled*); do echo 1 > $f; done # python3 >>> from socket import * >>> from scapy.all import * >>> >>> SRC_ADDR = DST_ADDR = "fe80::5054:ff:fe12:3456" >>> >>> pkt = IPv6(src=SRC_ADDR, dst=DST_ADDR) >>> pkt /= IPv6ExtHdrSegmentRouting(type=4, addresses=["11::", "22::"], segleft=1) >>> >>> sk = socket(AF_INET6, SOCK_RAW, IPPROTO_RAW) >>> sk.sendto(bytes(pkt), (DST_ADDR, 0)) For such a packet, we call ip6_route_input() to look up a route for the next destination in these three functions depending on the header type. * ipv6_rthdr_rcv() * ipv6_rpl_srh_rcv() * ipv6_srh_rcv() If no route is found, ip6_null_entry is set to skb, and the following dst_input(skb) calls ip6_pkt_drop(). Finally, in icmp6_dev(), we dereference skb_rt6_info(skb)->rt6i_idev->dev as the input device is the loopback interface. Then, we have to check if skb_rt6_info(skb)->rt6i_idev is NULL or not to avoid NULL pointer deref for ip6_null_entry. BUG: kernel NULL pointer dereference, address: 0000000000000000 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 0 PID: 157 Comm: python3 Not tainted 6.4.0-11996-gb121d614371c #35 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:icmp6_send (net/ipv6/icmp.c:436 net/ipv6/icmp.c:503) Code: fe ff ff 48 c7 40 30 c0 86 5d 83 e8 c6 44 1c 00 e9 c8 fc ff ff 49 8b 46 58 48 83 e0 fe 0f 84 4a fb ff ff 48 8b 80 d0 00 00 00 <48> 8b 00 44 8b 88 e0 00 00 00 e9 34 fb ff ff 4d 85 ed 0f 85 69 01 RSP: 0018:ffffc90000003c70 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000000000e0 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff888006d72a18 RBP: ffffc90000003d80 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc90000003d98 R11: 0000000000000040 R12: ffff888006d72a10 R13: 0000000000000000 R14: ffff8880057fb800 R15: ffffffff835d86c0 FS: 00007f9dc72ee740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000057b2000 CR4: 00000000007506f0 PKRU: 55555554 Call Trace: <IRQ> ip6_pkt_drop (net/ipv6/route.c:4513) ipv6_rthdr_rcv (net/ipv6/exthdrs.c:640 net/ipv6/exthdrs.c:686) ip6_protocol_deliver_rcu (net/ipv6/ip6_input.c:437 (discriminator 5)) ip6_input_finish (./include/linux/rcupdate.h:781 net/ipv6/ip6_input.c:483) __netif_receive_skb_one_core (net/core/dev.c:5455) process_backlog (./include/linux/rcupdate.h:781 net/core/dev.c:5895) __napi_poll (net/core/dev.c:6460) net_rx_action (net/core/dev.c:6529 net/core/dev.c:6660) __do_softirq (./arch/x86/include/asm/jump_label.h:27 ./include/linux/jump_label.h:207 ./include/trace/events/irq.h:142 kernel/softirq.c:554) do_softirq (kernel/softirq.c:454 kernel/softirq.c:441) </IRQ> <TASK> __local_bh_enable_ip (kernel/softirq.c:381) __dev_queue_xmit (net/core/dev.c:4231) ip6_finish_output2 (./include/net/neighbour.h:544 net/ipv6/ip6_output.c:135) rawv6_sendmsg (./include/net/dst.h:458 ./include/linux/netfilter.h:303 net/ipv6/raw.c:656 net/ipv6/raw.c:914) sock_sendmsg (net/socket.c:725 net/socket.c:748) __sys_sendto (net/socket.c:2134) __x64_sys_sendto (net/socket.c:2146 net/socket.c:2142 net/socket.c:2142) do_syscall_64 (arch/x86/entry/common.c:50 arch/x86/entry/common.c:80) entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:120) RIP: 0033:0x7f9dc751baea Code: d8 64 89 02 48 c7 c0 ff ff ff ff eb b8 0f 1f 00 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c0 75 15 b8 2c 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 7e c3 0f 1f 44 00 00 41 54 48 83 ec 30 44 89 RSP: 002b:00007ffe98712c38 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007ffe98712cf8 RCX: 00007f9dc751baea RDX: 0000000000000060 RSI: 00007f9dc6460b90 RDI: 0000000000000003 RBP: 00007f9dc56e8be0 R08: 00007ffe98712d70 R09: 000000000000001c R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: ffffffffc4653600 R14: 0000000000000001 R15: 00007f9dc6af5d1b </TASK> Modules linked in: CR2: 0000000000000000 ---[ end trace 0000000000000000 ]--- RIP: 0010:icmp6_send (net/ipv6/icmp.c:436 net/ipv6/icmp.c:503) Code: fe ff ff 48 c7 40 30 c0 86 5d 83 e8 c6 44 1c 00 e9 c8 fc ff ff 49 8b 46 58 48 83 e0 fe 0f 84 4a fb ff ff 48 8b 80 d0 00 00 00 <48> 8b 00 44 8b 88 e0 00 00 00 e9 34 fb ff ff 4d 85 ed 0f 85 69 01 RSP: 0018:ffffc90000003c70 EFLAGS: 00000286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 00000000000000e0 RDX: 0000000000000021 RSI: 0000000000000000 RDI: ffff888006d72a18 RBP: ffffc90000003d80 R08: 0000000000000000 R09: 0000000000000001 R10: ffffc90000003d98 R11: 0000000000000040 R12: ffff888006d72a10 R13: 0000000000000000 R14: ffff8880057fb800 R15: ffffffff835d86c0 FS: 00007f9dc72ee740(0000) GS:ffff88807dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000000 CR3: 00000000057b2000 CR4: 00000000007506f0 PKRU: 55555554 Kernel panic - not syncing: Fatal exception in interrupt Kernel Offset: disabled Fixes: 4832c30 ("net: ipv6: put host and anycast routes on device with address") Reported-by: Wang Yufen <wangyufen@huawei.com> Closes: https://lore.kernel.org/netdev/c41403a9-c2f6-3b7e-0c96-e1901e605cd0@huawei.com/ Signed-off-by: Kuniyuki Iwashima <kuniyu@amazon.com> Reviewed-by: David Ahern <dsahern@kernel.org> Reviewed-by: Eric Dumazet <edumazet@google.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Sasha Levin <sashal@kernel.org>
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Hi @Kwiboo,
Thanks for all your work on the rkvdec and hantro video decoders in the kernel and FFmpeg. Thanks to you I have been able to assemble a very capable media center using a Rockpro64 board and Kodi. It plays most videos very well, including 10-bit with full hardware acceleration :) . However I have found a few H.264 videos which show some artifacts / corruption when decoded with rkvdec, here are a couple of samples:
https://sigmaris.info/files/titles1.mkv
https://sigmaris.info/files/titles2.mkv
These two short clips are from movies and when played on Kodi the picture is mostly recognisable but there are a lot of blocky artifacts in the picture that look wrong (slightly wrong colours, or mixed with other nearby parts of the picture).
I've also noticed similar issues on the terrestrial HDTV broadcasts here in the UK, which are encoded in H.264. The corruption is similar but seems to get worse/better in cycles every 1-2 seconds, I guess this is related to the interval of I-frames being encoded in the broadcast. Here is a sample of HDTV:
https://sigmaris.info/files/bbc_1_hd.ts
Most other H.264 videos, including everything I've viewed on Youtube and Twitch live streams look 100% OK. I am mainly uploading these samples in case it helps finding bugs in the rkvdec driver or FFmpeg.
I am using this kernel based on 5.9.3 plus your branch: https://github.com/sigmaris/linux/releases/tag/5.9.3-rockpro64-ci
and this FFmpeg: https://github.com/sigmaris/FFmpeg/releases/tag/4.3.1-25_sigmaris
I am using the rkvdec driver to decode H.264, I haven't enabled H.264 decoding in the RK3399 hantro driver.
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