Encoder endofstream problem (lost few final frames) #24

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opened 2025-12-23 10:30:41 +01:00 by backuprepo · 2 comments

backuprepo commented

2025-12-23 10:30:41 +01:00

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Originally created by @mcerveny on GitHub (Mar 9, 2024).

Hello.
I found the problem in encoder logic.

if packet (encoded frame) is not available (still encoding), EAGAIN is returned
27136b05e0/libavcodec/rkmppenc.c (L687-L691)
error return is handled in encode function, *got_packet=0
27136b05e0/libavcodec/rkmppenc.c (L776-L779)
encoder loop check got_packet and if in draining state, ends draining and lost all remaining encoded packet
27136b05e0/libavcodec/encode.c (L353-L354)

I did not discover why "ffmpeg" loop does not suffer this problem but my program have this problem. So I try to add busy-loop over rkmpp_get_packet() (if loop is only to "get:" label it sometimes stops for few seconds, please review the logic):

diff --git a/libavcodec/rkmppenc.c b/libavcodec/rkmppenc.c
index 1688acc..afbb59f 100644
--- a/libavcodec/rkmppenc.c
+++ b/libavcodec/rkmppenc.c
@@ -774,6 +774,8 @@ send:
 
 get:
     ret = rkmpp_get_packet(avctx, packet);
+    if (!frame && ret == AVERROR(EAGAIN))
+        goto send;
     if (ret == AVERROR_EOF ||
         ret == AVERROR(EAGAIN))
         *got_packet = 0;

Typical problem (penultimate column shows PTS inserted to encoder, last column shows PTS outputted from encoder, so lost 2 frames (1456376400, 1456380000)):

main.c:712: flt->enc                     1456369200
main.c:709: >ENC
main.c:720: .ENC
main.c:744: enc->out                               1456358400
main.c:720: .ENC
main.c:744: enc->out                               1456362000
main.c:720: .ENC
main.c:709: >ENC
main.c:712: flt->enc                     1456372800
main.c:709: >ENC
main.c:712: flt->enc                     1456376400
main.c:709: >ENC
main.c:720: .ENC
main.c:744: enc->out                               1456365600
main.c:720: .ENC
main.c:709: >ENC
main.c:712: flt->enc                     1456380000
main.c:698: =send EOF to ENC (signaling EOF to encoder)
main.c:720: .ENC
main.c:744: enc->out                               1456369200
main.c:720: .ENC
[h264_rkmpp @ 0x557c23e3b0] End of stream
[h264_rkmpp @ 0x557c23e3b0] Wrote 0 bytes to encoder
[h264_rkmpp @ 0x557c23e3b0] Received a packet
main.c:744: enc->out                               1456372800
main.c:720: .ENC
[h264_rkmpp @ 0x557c23e3b0] End of stream
[h264_rkmpp @ 0x557c23e3b0] Wrote 0 bytes to encoder
[h264_rkmpp @ 0x557c23e3b0] Failed to get packet from encoder output queue: -11
main.c:733: =send EOF to OUT (received EOF from encoder)
======================= aframe 100 98

Originally created by @mcerveny on GitHub (Mar 9, 2024). Hello. I found the problem in encoder logic. 1) if packet (encoded frame) is not available (still encoding), EAGAIN is returned https://github.com/nyanmisaka/ffmpeg-rockchip/blob/27136b05e0742450a019d6bab80d840ac5fd6421/libavcodec/rkmppenc.c#L687-L691 2) error return is handled in encode function, *got_packet=0 https://github.com/nyanmisaka/ffmpeg-rockchip/blob/27136b05e0742450a019d6bab80d840ac5fd6421/libavcodec/rkmppenc.c#L776-L779 3) encoder loop check got_packet and if in draining state, ends draining and lost all remaining encoded packet https://github.com/nyanmisaka/ffmpeg-rockchip/blob/27136b05e0742450a019d6bab80d840ac5fd6421/libavcodec/encode.c#L353-L354 I did not discover why "ffmpeg" loop does not suffer this problem but my program have this problem. So I try to add busy-loop over rkmpp_get_packet() (if loop is only to "get:" label it sometimes stops for few seconds, please review the logic): ``` diff --git a/libavcodec/rkmppenc.c b/libavcodec/rkmppenc.c index 1688acc..afbb59f 100644 --- a/libavcodec/rkmppenc.c +++ b/libavcodec/rkmppenc.c @@ -774,6 +774,8 @@ send: get: ret = rkmpp_get_packet(avctx, packet); + if (!frame && ret == AVERROR(EAGAIN)) + goto send; if (ret == AVERROR_EOF || ret == AVERROR(EAGAIN)) *got_packet = 0; ``` Typical problem (penultimate column shows PTS inserted to encoder, last column shows PTS outputted from encoder, so lost 2 frames (1456376400, 1456380000)): ``` main.c:712: flt->enc 1456369200 main.c:709: >ENC main.c:720: .ENC main.c:744: enc->out 1456358400 main.c:720: .ENC main.c:744: enc->out 1456362000 main.c:720: .ENC main.c:709: >ENC main.c:712: flt->enc 1456372800 main.c:709: >ENC main.c:712: flt->enc 1456376400 main.c:709: >ENC main.c:720: .ENC main.c:744: enc->out 1456365600 main.c:720: .ENC main.c:709: >ENC main.c:712: flt->enc 1456380000 main.c:698: =send EOF to ENC (signaling EOF to encoder) main.c:720: .ENC main.c:744: enc->out 1456369200 main.c:720: .ENC [h264_rkmpp @ 0x557c23e3b0] End of stream [h264_rkmpp @ 0x557c23e3b0] Wrote 0 bytes to encoder [h264_rkmpp @ 0x557c23e3b0] Received a packet main.c:744: enc->out 1456372800 main.c:720: .ENC [h264_rkmpp @ 0x557c23e3b0] End of stream [h264_rkmpp @ 0x557c23e3b0] Wrote 0 bytes to encoder [h264_rkmpp @ 0x557c23e3b0] Failed to get packet from encoder output queue: -11 main.c:733: =send EOF to OUT (received EOF from encoder) ======================= aframe 100 98 ```

backuprepo

2025-12-23 10:30:41 +01:00

closed this issue
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backuprepo commented

2025-12-23 10:30:43 +01:00

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@nyanmisaka commented on GitHub (Mar 9, 2024):

@mcerveny I managed to find a ffmpeg command that can be used to reproduce the problem. And your patch did fix it.

It seems that ffmpeg is not expecting codec->encode() to return EAGAIN while the encoder is draining/at eof (!frame). So what you added makes sense.

ffmpeg -init_hw_device rkmpp \
-f lavfi -i color=c=cyan:s=1920x1080:d=4:r=25,format=nv12 \
-f lavfi -i testsrc2=s=960x540:d=4:r=25,format=bgra \
-lavfi "[0:v]hwupload[main];[1:v]hwupload[over];[main][over]overlay_rkrga=format=nv12:afbc=1:eof_action=repeat:repeatlast=1,scale_rkrga=w=1280:h=720:afbc=1" \
-c:v h264_rkmpp -v debug -y /tmp/100frames.mp4

@nyanmisaka commented on GitHub (Mar 9, 2024): @mcerveny I managed to find a ffmpeg command that can be used to reproduce the problem. And your patch did fix it. It seems that ffmpeg is not expecting `codec->encode()` to return EAGAIN while the encoder is draining/at eof `(!frame)`. So what you added makes sense. ``` ffmpeg -init_hw_device rkmpp \ -f lavfi -i color=c=cyan:s=1920x1080:d=4:r=25,format=nv12 \ -f lavfi -i testsrc2=s=960x540:d=4:r=25,format=bgra \ -lavfi "[0:v]hwupload[main];[1:v]hwupload[over];[main][over]overlay_rkrga=format=nv12:afbc=1:eof_action=repeat:repeatlast=1,scale_rkrga=w=1280:h=720:afbc=1" \ -c:v h264_rkmpp -v debug -y /tmp/100frames.mp4 ```

backuprepo commented

2025-12-23 10:30:43 +01:00

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@nyanmisaka commented on GitHub (Mar 10, 2024):

Closed by 7a0200b

@nyanmisaka commented on GitHub (Mar 10, 2024): Closed by 7a0200b