memory leaks in ff_frame_pool_get()

[Suhwan]

Summary of the bug:
There are memory leaks in ff_frame_pool_get()
How to reproduce:

% ffmpeg_g -t 3 -y -i $PoC -filter_complex colorspace -target dvd -loglevel 0 tmp.ads

ffmpeg version N-95441-g0ae6fb276b Copyright (c) 2000-2019 the FFmpeg developers
built with clang version 6.0.0-1ubuntu2 (tags/RELEASE_600/final)
configuration: --cc=clang --cxx=clang++ --ld=clang --enable-debug

Here's Valgrind log

==6446== HEAP SUMMARY:
==6446==     in use at exit: 100,746 bytes in 33 blocks
==6446==   total heap usage: 3,265 allocs, 3,232 frees, 2,295,813 bytes allocated
==6446== 
==6446== 50,357 (536 direct, 49,821 indirect) bytes in 1 blocks are definitely lost in loss record 12 of 13
==6446==    at 0x9FE2E76: memalign (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==6446==    by 0x9FE2F91: posix_memalign (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==6446==    by 0x592E949: av_malloc (mem.c:87)
==6446==    by 0x592E949: av_mallocz (mem.c:238)
==6446==    by 0x5902ADD: av_frame_alloc (frame.c:191)
==6446==    by 0x64FBD5: ff_frame_pool_get (framepool.c:201)
==6446==    by 0xFB8A9C: ff_default_get_video_buffer (video.c:90)
==6446==    by 0xD20033: scale_frame (vf_scale.c:460)
==6446==    by 0xD1F24C: filter_frame (vf_scale.c:549)
==6446==    by 0x5CFE9C: ff_filter_frame_framed (avfilter.c:1084)
==6446==    by 0x5CFE9C: ff_filter_frame_to_filter (avfilter.c:1232)
==6446==    by 0x5CFE9C: ff_filter_activate_default (avfilter.c:1281)
==6446==    by 0x5CFE9C: ff_filter_activate (avfilter.c:1443)
==6446==    by 0x5F42A4: push_frame (buffersrc.c:187)
==6446==    by 0x5F42A4: av_buffersrc_add_frame_internal (buffersrc.c:261)
==6446==    by 0x5F2E7D: av_buffersrc_add_frame_flags (buffersrc.c:170)
==6446==    by 0x4CAD5F: ifilter_send_frame (ffmpeg.c:2186)
==6446==    by 0x4CAD5F: send_frame_to_filters (ffmpeg.c:2260)
==6446== 
==6446== 50,357 (536 direct, 49,821 indirect) bytes in 1 blocks are definitely lost in loss record 13 of 13
==6446==    at 0x9FE2E76: memalign (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==6446==    by 0x9FE2F91: posix_memalign (in /usr/lib/valgrind/vgpreload_memcheck-amd64-linux.so)
==6446==    by 0x592E949: av_malloc (mem.c:87)
==6446==    by 0x592E949: av_mallocz (mem.c:238)
==6446==    by 0x5902ADD: av_frame_alloc (frame.c:191)
==6446==    by 0x64FBD5: ff_frame_pool_get (framepool.c:201)
==6446==    by 0xFB8A9C: ff_default_get_video_buffer (video.c:90)
==6446==    by 0x7FD3D4: filter_frame (vf_colorspace.c:770)
==6446==    by 0x5CFE9C: ff_filter_frame_framed (avfilter.c:1084)
==6446==    by 0x5CFE9C: ff_filter_frame_to_filter (avfilter.c:1232)
==6446==    by 0x5CFE9C: ff_filter_activate_default (avfilter.c:1281)
==6446==    by 0x5CFE9C: ff_filter_activate (avfilter.c:1443)
==6446==    by 0x5F42BE: push_frame (buffersrc.c:187)
==6446==    by 0x5F42BE: av_buffersrc_add_frame_internal (buffersrc.c:261)
==6446==    by 0x5F2E7D: av_buffersrc_add_frame_flags (buffersrc.c:170)
==6446==    by 0x4CAD5F: ifilter_send_frame (ffmpeg.c:2186)
==6446==    by 0x4CAD5F: send_frame_to_filters (ffmpeg.c:2260)
==6446==    by 0x4A07BB: decode_video (ffmpeg.c:2459)
==6446==    by 0x4A07BB: process_input_packet (ffmpeg.c:2613)
==6446== 
==6446== LEAK SUMMARY:
==6446==    definitely lost: 1,072 bytes in 2 blocks
==6446==    indirectly lost: 99,642 bytes in 30 blocks
==6446==      possibly lost: 0 bytes in 0 blocks
==6446==    still reachable: 32 bytes in 1 blocks
==6446==         suppressed: 0 bytes in 0 blocks
==6446== Reachable blocks (those to which a pointer was found) are not shown.
==6446== To see them, rerun with: --leak-check=full --show-leak-kinds=all
==6446== 
==6446== For counts of detected and suppressed errors, rerun with: -v
==6446== ERROR SUMMARY: 2 errors from 2 contexts (suppressed: 0 from 0)

Please confirm.
Thanks

[Suhwan]

poc