I use grabber and record for video processing vs directly using ffmpeg has different effects.

javacv version 1.5.9 ffmpeg version 6.0

I have two test cases, one is to use ffmpeg directly through javacv, and the other is to process videos through grabber and recorder in Java. The code is as follows

@Test
public void testFfmpegWithJavaCV() throws IOException, InterruptedException {
    String inputPath = "D:\\video\\test.mp4";
    String outputPath = "D:\\video\\output_ffmpeg_500k.mp4";
    String ffmpeg = Loader.load(org.bytedeco.ffmpeg.ffmpeg.class);
    long startTime = System.currentTimeMillis();
    ProcessBuilder pb = new ProcessBuilder(ffmpeg, "-i", inputPath, "-vcodec", "h264", "-b:v", "500k",  "-bufsize", "2M", outputPath);
    pb.inheritIO().start().waitFor();
    log.info("Compression completed in {}ms", System.currentTimeMillis() - startTime); 
}


@Test
public void testRecord() throws FrameRecorder.Exception, FrameGrabber.Exception {
    String inputPath = "D:\\video\\test.mp4";
    String outputPath = "D:\\video\\output_javacv_500k.mp4";
    try (FFmpegFrameGrabber grabber = new FFmpegFrameGrabber(inputPath);
         ) {
        grabber.start();
        FFmpegFrameRecorder recorder = new FFmpegFrameRecorder(outputPath, grabber.getImageWidth(), grabber.getImageHeight(),grabber.getAudioChannels());
        recorder.setVideoCodec(avcodec.AV_CODEC_ID_H264);
        recorder.setFrameRate(grabber.getFrameRate());
        recorder.setVideoBitrate(500 * 1000);
        recorder.setOption("bufsize", "2M");

        recorder.setAudioCodecName("copy");
        recorder.setAudioBitrate(grabber.getAudioBitrate());
        recorder.start();
        long startTime = System.currentTimeMillis();
        Frame frame;
        while ((frame = grabber.grab()) != null) {
            recorder.record(frame);
        }
        recorder.stop();
        recorder.release();
        log.info("Compression completed in {}ms", System.currentTimeMillis() - startTime);
    }
}

@Test
public void testFfmpegWithCmd() throws IOException, InterruptedException {
    String inputPath = "D:\\视频素材\\35532179568-1-192.mp4";
    String outputPath = "D:\\视频素材\\output_ffmpeg_500k.mp4";
    String ffmpegcmd = "E:\\server\\ffmpeg-6.0-essentials\\bin\\ffmpeg.exe";
    long startTime = System.currentTimeMillis();
    ProcessBuilder pb = new ProcessBuilder(ffmpegcmd, "-i", inputPath, "-vcodec", "h264", "-b:v", "500k",  "-bufsize", "2M", outputPath);
    pb.inheritIO().start().waitFor();
    log.info("Compression completed in {}ms", System.currentTimeMillis() - startTime);
}

testFfmpegWithJavaCV log output

19:54:28.673 [main] INFO com.macronsan.FfmpegTest - Compression completed in 41226ms ffmpeg version 6.0 Copyright (c) 2000-2023 the FFmpeg developers built with gcc 10.3.0 (Rev8, Built by MSYS2 project) configuration: --prefix=.. --disable-iconv --disable-opencl --disable-vulkan --disable-sdl2 --disable-bzlib --disable-lzma --disable-linux-perf --disable-xlib --enable-shared --enable-version3 --enable-runtime-cpudetect --enable-zlib --enable-libmp3lame --enable-libspeex --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-openssl --enable-libopenh264 --enable-libvpx --enable-libfreetype --enable-libopus --enable-libxml2 --enable-libsrt --enable-libwebp --enable-libaom --enable-libsvtav1 --enable-cuda --enable-cuvid --enable-nvenc --enable-libmfx --enable-w32threads --enable-indev=dshow --target-os=mingw32 --cc='gcc -m64' --extra-cflags='-DLIBXML_STATIC -I../include/ -I../include/libxml2 -I../include/mfx/ -I../include/svt-av1' --extra-ldflags=-L../lib/ --extra-libs='-static-libgcc -static-libstdc++ -Wl,-Bstatic -lstdc++ -lgcc_eh -lWs2_32 -lcrypt32 -lpthread -lz -lm -Wl,-Bdynamic -lole32 -luuid' libavutil 58. 2.100 / 58. 2.100 libavcodec 60. 3.100 / 60. 3.100 libavformat 60. 3.100 / 60. 3.100 libavdevice 60. 1.100 / 60. 1.100 libavfilter 9. 3.100 / 9. 3.100 libswscale 7. 1.100 / 7. 1.100 libswresample 4. 10.100 / 4. 10.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\视频素材\35532179568-1-192.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf59.27.100 description : Packed by Bilibili XCoder v2.0.2 Duration: 00:03:39.41, start: 0.000000, bitrate: 1067 kb/s Stream #0:00x1: Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 859 kb/s, 30 fps, 30 tbr, 16k tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] Stream #0:10x2: Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 198 kb/s (default) Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] Stream mapping: Stream #0:0 -> #0:0 (h264 (native) -> h264 (libopenh264)) Stream #0:1 -> #0:1 (aac (native) -> aac (native)) Press [q] to stop, [?] for help [libopenh264 @ 000001c031135f00] [OpenH264] this = 0x000001c0332fefa0, Warning:layerId(0) doesn't support profile(578), change to UNSPECIFIC profile [libopenh264 @ 000001c031135f00] [OpenH264] this = 0x000001c0332fefa0, Warning:bEnableFrameSkip = 0,bitrate can't be controlled for RC_QUALITY_MODE,RC_BITRATE_MODE and RC_TIMESTAMP_MODE without enabling skip frame. Output #0, mp4, to 'D:\视频素材\output_javacv_ffmpeg_500k.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 description : Packed by Bilibili XCoder v2.0.2 encoder : Lavf60.3.100 Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 500 kb/s, 30 fps, 15360 tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] encoder : Lavc60.3.100 libopenh264 Side data: cpb: bitrate max/min/avg: 500000/0/500000 buffer size: 0 vbv_delay: N/A Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default) Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] encoder : Lavc60.3.100 aac frame= 6582 fps=160 q=-0.0 Lsize= 17327kB time=00:03:39.38 bitrate= 647.0kbits/s speed=5.33x
video:13703kB audio:3441kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.067410% [aac @ 000001c02f86b740] Qavg: 424.198

testRecord log output

19:57:16.675 [main] INFO com.macronsan.FfmpegTest - Compression completed in 56071ms Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\视频素材\35532179568-1-192.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf59.27.100 description : Packed by Bilibili XCoder v2.0.2 Duration: 00:03:39.41, start: 0.000000, bitrate: 1067 kb/s Stream #0:00x1: Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 859 kb/s, 30 fps, 30 tbr, 16k tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] Stream #0:10x2: Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 198 kb/s (default) Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] [libopenh264 @ 0000000025958dc0] [OpenH264] this = 0x0000000024021890, Warning:layerId(0) doesn't support profile(578), change to UNSPECIFIC profile [libopenh264 @ 0000000025958dc0] [OpenH264] this = 0x0000000024021890, Warning:bEnableFrameSkip = 0,bitrate can't be controlled for RC_QUALITY_MODE,RC_BITRATE_MODE and RC_TIMESTAMP_MODE without enabling skip frame. Output #0, mp4, to 'D:\视频素材\output_javacv_500k.mp4': Metadata: encoder : Lavf60.3.100 Stream #0:0: Video: h264 (Constrained Baseline) (avc1 / 0x31637661), yuv420p, 1280x720, q=2-31, 500 kb/s, 30 fps, 658203 tbn Stream #0:1: Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 198 kb/s [aac @ 00000000259575c0] Qavg: 405.536 [aac @ 00000000259575c0] 1 frames left in the queue on closing

testFfmpegWithCmd log output

19:58:35.378 [main] INFO com.macronsan.FfmpegTest - Compression completed in 24832ms ffmpeg version 6.0-essentials_build-www.gyan.dev Copyright (c) 2000-2023 the FFmpeg developers built with gcc 12.2.0 (Rev10, Built by MSYS2 project) configuration: --enable-gpl --enable-version3 --enable-static --disable-w32threads --disable-autodetect --enable-fontconfig --enable-iconv --enable-gnutls --enable-libxml2 --enable-gmp --enable-bzlib --enable-lzma --enable-zlib --enable-libsrt --enable-libssh --enable-libzmq --enable-avisynth --enable-sdl2 --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxvid --enable-libaom --enable-libopenjpeg --enable-libvpx --enable-mediafoundation --enable-libass --enable-libfreetype --enable-libfribidi --enable-libvidstab --enable-libvmaf --enable-libzimg --enable-amf --enable-cuda-llvm --enable-cuvid --enable-ffnvcodec --enable-nvdec --enable-nvenc --enable-d3d11va --enable-dxva2 --enable-libvpl --enable-libgme --enable-libopenmpt --enable-libopencore-amrwb --enable-libmp3lame --enable-libtheora --enable-libvo-amrwbenc --enable-libgsm --enable-libopencore-amrnb --enable-libopus --enable-libspeex --enable-libvorbis --enable-librubberband libavutil 58. 2.100 / 58. 2.100 libavcodec 60. 3.100 / 60. 3.100 libavformat 60. 3.100 / 60. 3.100 libavdevice 60. 1.100 / 60. 1.100 libavfilter 9. 3.100 / 9. 3.100 libswscale 7. 1.100 / 7. 1.100 libswresample 4. 10.100 / 4. 10.100 libpostproc 57. 1.100 / 57. 1.100 Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'D:\视频素材\35532179568-1-192.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 encoder : Lavf59.27.100 description : Packed by Bilibili XCoder v2.0.2 Duration: 00:03:39.41, start: 0.000000, bitrate: 1067 kb/s Stream #0:00x1: Video: h264 (High) (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], 859 kb/s, 30 fps, 30 tbr, 16k tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] Stream #0:10x2: Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 198 kb/s (default) Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] Stream mapping: Stream #0:0 -> #0:0 (h264 (native) -> h264 (libx264)) Stream #0:1 -> #0:1 (aac (native) -> aac (native)) Press [q] to stop, [?] for help [libx264 @ 000001edbf5b5800] VBV maxrate unspecified, assuming CBR [libx264 @ 000001edbf5b5800] using SAR=1/1 [libx264 @ 000001edbf5b5800] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2 [libx264 @ 000001edbf5b5800] profile High, level 3.1, 4:2:0, 8-bit [libx264 @ 000001edbf5b5800] 264 - core 164 r3106 eaa68fa - H.264/MPEG-4 AVC codec - Copyleft 2003-2023 - http://www.videolan.org/x264.html - options: cabac=1 ref=3 deblock=1:0:0 analyse=0x3:0x113 me=hex subme=7 psy=1 psy_rd=1.00:0.00 mixed_ref=1 me_range=16 chroma_me=1 trellis=1 8x8dct=1 cqm=0 deadzone=21,11 fast_pskip=1 chroma_qp_offset=-2 threads=18 lookahead_threads=3 sliced_threads=0 nr=0 decimate=1 interlaced=0 bluray_compat=0 constrained_intra=0 bframes=3 b_pyramid=2 b_adapt=1 b_bias=0 direct=1 weightb=1 open_gop=0 weightp=2 keyint=250 keyint_min=25 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=cbr mbtree=1 bitrate=500 ratetol=1.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 vbv_maxrate=500 vbv_bufsize=2000 nal_hrd=none filler=0 ip_ratio=1.40 aq=1:1.00 Output #0, mp4, to 'D:\视频素材\output_ffmpeg_500k.mp4': Metadata: major_brand : isom minor_version : 512 compatible_brands: isomiso2avc1mp41 description : Packed by Bilibili XCoder v2.0.2 encoder : Lavf60.3.100 Stream #0:0(und): Video: h264 (avc1 / 0x31637661), yuv420p(tv, bt709, progressive), 1280x720 [SAR 1:1 DAR 16:9], q=2-31, 500 kb/s, 30 fps, 15360 tbn (default) Metadata: handler_name : VideoHandler vendor_id : [0][0][0][0] encoder : Lavc60.3.100 libx264 Side data: cpb: bitrate max/min/avg: 0/0/500000 buffer size: 2000000 vbv_delay: N/A Stream #0:1(und): Audio: aac (LC) (mp4a / 0x6134706D), 44100 Hz, stereo, fltp, 128 kb/s (default) Metadata: handler_name : SoundHandler vendor_id : [0][0][0][0] encoder : Lavc60.3.100 aac frame= 6582 fps=298 q=-1.0 Lsize= 16735kB time=00:03:39.38 bitrate= 624.9kbits/s speed=9.93x
video:13060kB audio:3441kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 1.416561% [libx264 @ 000001edbf5b5800] frame I:31 Avg QP:23.97 size: 51399 [libx264 @ 000001edbf5b5800] frame P:1857 Avg QP:26.29 size: 4609 [libx264 @ 000001edbf5b5800] frame B:4694 Avg QP:29.91 size: 686 [libx264 @ 000001edbf5b5800] consecutive B-frames: 1.4% 9.8% 2.4% 86.4% [libx264 @ 000001edbf5b5800] mb I I16..4: 27.3% 57.1% 15.6% [libx264 @ 000001edbf5b5800] mb P I16..4: 2.6% 2.0% 0.0% P16..4: 30.3% 3.9% 2.6% 0.0% 0.0% skip:58.6% [libx264 @ 000001edbf5b5800] mb B I16..4: 0.0% 0.0% 0.0% B16..8: 21.9% 0.1% 0.0% direct: 0.0% skip:77.9% L0:41.0% L1:58.8% BI: 0.2% [libx264 @ 000001edbf5b5800] 8x8 transform intra:46.6% inter:85.2% [libx264 @ 000001edbf5b5800] coded y,uvDC,uvAC intra: 21.4% 37.3% 9.2% inter: 2.2% 3.1% 0.1% [libx264 @ 000001edbf5b5800] i16 v,h,dc,p: 17% 45% 10% 29% [libx264 @ 000001edbf5b5800] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 9% 26% 46% 2% 3% 2% 7% 1% 4% [libx264 @ 000001edbf5b5800] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 9% 43% 11% 4% 6% 3% 14% 2% 7% [libx264 @ 000001edbf5b5800] i8c dc,h,v,p: 58% 31% 8% 3% [libx264 @ 000001edbf5b5800] Weighted P-Frames: Y:2.4% UV:1.2% [libx264 @ 000001edbf5b5800] ref P L0: 62.6% 15.2% 15.9% 6.3% 0.0% [libx264 @ 000001edbf5b5800] ref B L0: 91.7% 6.8% 1.5% [libx264 @ 000001edbf5b5800] ref B L1: 97.1% 2.9% [libx264 @ 000001edbf5b5800] kb/s:487.61 [aac @ 000001edbf5b6d40] Qavg: 424.198

test result

output size：testFfmpegWithJavaCV output video is 16.3M ; testRecord output vide is 18.7M testFfmpegWithCmd 16.3M Execution time : testFfmpegWithJavaCV 41s; testRecord 56s ； testFfmpegWithCmd 24s

why result has different effects? Looking forward to your reply