MJPEG issue at certain settings

[alvestrand]

The setting -qmin 50 -qmax 722 seems to generate an error on BQMall for MJPEG @1200 kbps.

/home/hta/code/compare-codecs/tools/ffmpeg -loglevel warning -s 832x480 -i video/mpeg_video/BQMall_832x480_60.yuv -codec:v mjpeg -qmax 722 -qmin 50 -b:v 1200k -y /home/hta/code/compare-codecs/workdir/mjpeg/fd8f0e24053d/1200/BQMall_832x480_60.mjpeg
[rawvideo @ 0x1b48e20] Estimating duration from bitrate, this may be inaccurate
[swscaler @ 0x1b300c0] deprecated pixel format used, make sure you did set range correctly
Encode took 1.400000 CPU seconds 1.470000 clock seconds
/home/hta/code/compare-codecs/tools/ffmpeg -loglevel warning -codec:v mjpeg -i /home/hta/code/compare-codecs/workdir/mjpeg/fd8f0e24053d/1200/BQMall_832x480_60.mjpeg /home/hta/code/compare-codecs/workdir/mjpeg/fd8f0e24053d/1200/BQMall_832x480_60tempyuvfile.yuv
/home/hta/code/compare-codecs/workdir/mjpeg/fd8f0e24053d/1200/BQMall_832x480_60.mjpeg: Invalid data found when processing input

Settings that completed successfully:

7a2b7def4a12 -848.682010 -qmax 597
e3fef2f71b05 -530.719020 -qmax 597 -qmin 58
b4895ab262ea -499.714020 -qmax 598 -qmin 69
278ae022d480 -499.714020 -qmax 626 -qmin 69
366f29e2de05 -504.051020 -qmax 722 -qmin 67
456420d31ede -848.682010 -qmax 722
56c8aea054b6 -499.714020 -qmax 722 -qmin 69
f1306ea6b766 -499.714020 -qmax 827 -qmin 69
5499167d9533 -848.682010 -qmax 943
7df43d1fe8ce -499.714020 -qmax 943 -qmin 69
e8a589627343 -511.853020 -qmax 943 -qmin 64
d31668749543 -499.714020 -qmax 985 -qmin 69
1a5518512496 -499.714020 -qmax 1024 -qmin 69

[alvestrand]

-qmax 842 -qmin 50 also fails. So does -qmax 842 -qmin 49.
For qmax 842 we have working 48 and 54.
At rate 2000, -qmin 49 -qmax 842 also fails. 48 and 54 succeed.