我正在开发一款 C# 图像采集软件，其中我将获取的图像编译成视频。
目前，我通过从一组图像中创建视频来执行此操作，一旦图像数达到所需的输出 FPS，为了解决这个问题，我们将使用 5 FPS。它将等到有 5 张图像，这样它就可以为基础视频渲染 1 秒的素材，新帧将添加到其中。要生成此视频，我使用以下命令：
-framerate 5 -start_number 1 -i "C:\path\to\image\Image_%05d.jpg" -c:v libx264 -pix_fmt yuv420p -r 5 "C:\path\to\output\output.mp4"
探头输出：
ffmpeg version N-86994-g92da230 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 7.1.0 (GCC)
configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
libavutil 55. 74.100 / 55. 74.100
libavcodec 57.102.100 / 57.102.100
libavformat 57. 76.100 / 57. 76.100
libavdevice 57. 7.100 / 57. 7.100
libavfilter 6. 99.100 / 6. 99.100
libswscale 4. 7.102 / 4. 7.102
libswresample 2. 8.100 / 2. 8.100
libpostproc 54. 6.100 / 54. 6.100
Input #0, image2, from 'B00375_EOL_%05d.jpg':
Duration: 00:00:02.40, start: 0.000000, bitrate: N/A
Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1200x1200 [SAR 144:144 DAR 1:1], 5 fps, 5 tbr, 5 tbn, 5 tbc
Stream mapping:
Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[swscaler @ 0553cfc0] deprecated pixel format used, make sure you did set range correctly
[libx264 @ 05491120] using SAR=1/1
[libx264 @ 05491120] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 05491120] profile High, level 4.0
[libx264 @ 05491120] 264 - core 152 r2851 ba24899 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - 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=12 lookahead_threads=2 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=5 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'output.mp4':
Metadata:
encoder : Lavf57.76.100
Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1200x1200 [SAR 1:1 DAR 1:1], q=-1--1, 5 fps, 10240 tbn, 5 tbc
Metadata:
encoder : Lavc57.102.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame= 12 fps=0.0 q=-1.0 Lsize= 187kB time=00:00:01.80 bitrate= 852.8kbits/s speed=2.76x
video:186kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.490686%
[libx264 @ 05491120] frame I:2 Avg QP:14.80 size: 23424
[libx264 @ 05491120] frame P:9 Avg QP:15.59 size: 14619
[libx264 @ 05491120] frame B:1 Avg QP:15.13 size: 11846
[libx264 @ 05491120] consecutive B-frames: 83.3% 16.7% 0.0% 0.0%
[libx264 @ 05491120] mb I I16..4: 27.4% 71.2% 1.4%
[libx264 @ 05491120] mb P I16..4: 15.6% 72.7% 0.2% P16..4: 2.8% 0.8% 0.7% 0.0% 0.0% skip: 7.2%
[libx264 @ 05491120] mb B I16..4: 5.3% 31.8% 0.0% B16..8: 13.6% 8.8% 0.7% direct: 7.9% skip:31.8% L0:93.9% L1: 5.1% BI: 1.0%
[libx264 @ 05491120] 8x8 transform intra:80.1% inter:91.7%
[libx264 @ 05491120] coded y,uvDC,uvAC intra: 22.2% 25.1% 4.7% inter: 8.5% 14.4% 0.8%
[libx264 @ 05491120] i16 v,h,dc,p: 38% 31% 7% 24%
[libx264 @ 05491120] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 52% 21% 23% 1% 1% 0% 1% 1% 1%
[libx264 @ 05491120] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 30% 34% 14% 3% 3% 4% 3% 4% 3%
[libx264 @ 05491120] i8c dc,h,v,p: 65% 18% 14% 3%
[libx264 @ 05491120] Weighted P-Frames: Y:0.0% UV:0.0%
[libx264 @ 05491120] ref P L0: 67.1% 9.6% 20.2% 3.1%
[libx264 @ 05491120] kb/s:634.23
从这里我生成短的单帧视频附加到视频末尾以添加新帧，这是通过以下命令完成的：
-framerate 5 -loop 1 -i "C:\path\to\image\new_image.jpg" -c:v libx264 -pix_fmt yuv420p -t 0.2 -r 5 "C:\path\to\output\new_frame.mp4"
探头输出：
ffmpeg version N-86994-g92da230 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 7.1.0 (GCC)
configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
libavutil 55. 74.100 / 55. 74.100
libavcodec 57.102.100 / 57.102.100
libavformat 57. 76.100 / 57. 76.100
libavdevice 57. 7.100 / 57. 7.100
libavfilter 6. 99.100 / 6. 99.100
libswscale 4. 7.102 / 4. 7.102
libswresample 2. 8.100 / 2. 8.100
libpostproc 54. 6.100 / 54. 6.100
Input #0, image2, from 'B00375_PRC_00001.jpg':
Duration: 00:00:00.20, start: 0.000000, bitrate: 880 kb/s
Stream #0:0: Video: mjpeg, yuvj420p(pc, bt470bg/unknown/unknown), 1200x1200 [SAR 144:144 DAR 1:1], 5 fps, 5 tbr, 5 tbn, 5 tbc
Stream mapping:
Stream #0:0 -> #0:0 (mjpeg (native) -> h264 (libx264))
Press [q] to stop, [?] for help
[swscaler @ 03ba0fe0] deprecated pixel format used, make sure you did set range correctly
[libx264 @ 03b0e2e0] using SAR=1/1
[libx264 @ 03b0e2e0] using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX FMA3 BMI2 AVX2
[libx264 @ 03b0e2e0] profile High, level 4.0
[libx264 @ 03b0e2e0] 264 - core 152 r2851 ba24899 - H.264/MPEG-4 AVC codec - Copyleft 2003-2017 - 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=12 lookahead_threads=2 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=5 scenecut=40 intra_refresh=0 rc_lookahead=40 rc=crf mbtree=1 crf=23.0 qcomp=0.60 qpmin=0 qpmax=69 qpstep=4 ip_ratio=1.40 aq=1:1.00
Output #0, mp4, to 'new_frame.mp4':
Metadata:
encoder : Lavf57.76.100
Stream #0:0: Video: h264 (libx264) (avc1 / 0x31637661), yuv420p, 1200x1200 [SAR 1:1 DAR 1:1], q=-1--1, 5 fps, 10240 tbn, 5 tbc
Metadata:
encoder : Lavc57.102.100 libx264
Side data:
cpb: bitrate max/min/avg: 0/0/0 buffer size: 0 vbv_delay: -1
frame= 1 fps=0.0 q=23.0 Lsize= 15kB time=00:00:00.00 bitrate=1287020.4kbits/s speed=0.000332x
video:15kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 5.465249%
[libx264 @ 03b0e2e0] frame I:1 Avg QP:15.27 size: 14260
[libx264 @ 03b0e2e0] mb I I16..4: 19.3% 79.8% 0.9%
[libx264 @ 03b0e2e0] 8x8 transform intra:79.8%
[libx264 @ 03b0e2e0] coded y,uvDC,uvAC intra: 19.1% 10.8% 0.1%
[libx264 @ 03b0e2e0] i16 v,h,dc,p: 35% 49% 6% 10%
[libx264 @ 03b0e2e0] i8 v,h,dc,ddl,ddr,vr,hd,vl,hu: 50% 22% 26% 0% 1% 0% 1% 0% 0%
[libx264 @ 03b0e2e0] i4 v,h,dc,ddl,ddr,vr,hd,vl,hu: 34% 21% 16% 4% 3% 6% 4% 5% 5%
[libx264 @ 03b0e2e0] i8c dc,h,v,p: 67% 18% 14% 1%
[libx264 @ 03b0e2e0] kb/s:570.40
此时这两个输出文件都很好。“主”视频生成持续 1 秒，文件属性中显示 5 FPS，单帧也是如此，它持续 0.2 秒，属性中显示 5 FPS。然后通过以下命令将这些文件合并：
-f concat -i concat.txt -auto_convert 1 -c copy join_vid.mp4 其中 concat.txt 如下所示：
文件‘output.mp4’
文件‘new_frame.mp4’
探头输出：
ffmpeg version N-86994-g92da230 Copyright (c) 2000-2017 the FFmpeg developers
built with gcc 7.1.0 (GCC)
configuration: --enable-gpl --enable-version3 --enable-cuda --enable-cuvid --enable-d3d11va --enable-dxva2 --enable-libmfx --enable-nvenc --enable-avisynth --enable-bzlib --enable-fontconfig --enable-frei0r --enable-gnutls --enable-iconv --enable-libass --enable-libbluray --enable-libbs2b --enable-libcaca --enable-libfreetype --enable-libgme --enable-libgsm --enable-libilbc --enable-libmodplug --enable-libmp3lame --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenh264 --enable-libopenjpeg --enable-libopus --enable-librtmp --enable-libsnappy --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libtwolame --enable-libvidstab --enable-libvo-amrwbenc --enable-libvorbis --enable-libvpx --enable-libwavpack --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxavs --enable-libxvid --enable-libzimg --enable-lzma --enable-zlib
libavutil 55. 74.100 / 55. 74.100
libavcodec 57.102.100 / 57.102.100
libavformat 57. 76.100 / 57. 76.100
libavdevice 57. 7.100 / 57. 7.100
libavfilter 6. 99.100 / 6. 99.100
libswscale 4. 7.102 / 4. 7.102
libswresample 2. 8.100 / 2. 8.100
libpostproc 54. 6.100 / 54. 6.100
[mov,mp4,m4a,3gp,3g2,mj2 @ 052d8700] Auto-inserting h264_mp4toannexb bitstream filter
Input #0, concat, from 'concat.txt':
Duration: N/A, start: 0.000000, bitrate: 636 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1200x1200 [SAR 1:1 DAR 1:1], 636 kb/s, 5 fps, 5 tbr, 10240 tbn, 10 tbc
Metadata:
handler_name : VideoHandler
Output #0, mp4, to 'joined_vid.mp4':
Metadata:
encoder : Lavf57.76.100
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 1200x1200 [SAR 1:1 DAR 1:1], q=2-31, 636 kb/s, 5 fps, 5 tbr, 10240 tbn, 10240 tbc
Metadata:
handler_name : VideoHandler
Stream mapping:
Stream #0:0 -> #0:0 (copy)
Press [q] to stop, [?] for help
[mov,mp4,m4a,3gp,3g2,mj2 @ 052d8700] Auto-inserting h264_mp4toannexb bitstream filter
frame= 13 fps=0.0 q=-1.0 Lsize= 202kB time=00:00:02.40 bitrate= 690.0kbits/s speed= 135x
video:201kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 0.470814%
从这里开始，新创建的“joined_vid.mp4”的 FPS 会下降，通常为 4 FPS（但曾见过它直接下降到 3 FPS），如图 1 所示。当我逐步添加更多帧并获取新图像时，FPS 会继续下降，直到达到 1 FPS，然后保持在 1。
我的问题是如何才能将我的新图像附加到视频末尾，而无需
- 丢帧
- 每添加一张新图像就必须重新渲染整个视频
- 降低输出文件的 FPS
非常感谢您的帮助，因为这个问题目前让我很困惑！
答案1
这确实是由于 H264 PTS 生成错误造成的。评论中的建议对我有用。但文章末尾的方法也有效。
初始文件命令：
ffmpeg -framerate 5 -start_number 1 -t 1 -i "f%d.png" -c:v libx264 -pix_fmt yuv420p -r 5 -bf 0 initial.mp4
单独帧的命令：
ffmpeg -framerate 5 -i "f6.png" -c:v libx264 -pix_fmt yuv420p -bf 0 -r 5 next1.mp4
...
ffmpeg -framerate 5 -i "f10.png" -c:v libx264 -pix_fmt yuv420p -bf 0 -r 5 next5.mp4
单一联接：
列表.txt：
file initial.mp4
file next1.mp4
和
ffmpeg -f concat -i list.txt -auto_convert 1 -c copy with6.mp4
with6.mp4：
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'with6.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.2.100
Duration: 00:00:01.20, start: 0.000000, bitrate: 129 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x240 [SAR 1:1 DAR 4:3], 124 kb/s, 5 fps, 5 tbr, 10240 tbn, 10 tbc (default)
Metadata:
handler_name : VideoHandler
立即加入其他人：
file with6.mp4
file next2.mp4
file next3.mp4
file next4.mp4
file next5.mp4
和
ffmpeg -f concat -i list.txt -auto_convert 1 -c copy with6.mp4
with10.mp4：
Input #0, mov,mp4,m4a,3gp,3g2,mj2, from 'with10.mp4':
Metadata:
major_brand : isom
minor_version : 512
compatible_brands: isomiso2avc1mp41
encoder : Lavf58.2.100
Duration: 00:00:02.00, start: 0.000000, bitrate: 168 kb/s
Stream #0:0(und): Video: h264 (High) (avc1 / 0x31637661), yuv420p, 320x240 [SAR 1:1 DAR 4:3], 165 kb/s, 5 fps, 5 tbr, 10240 tbn, 10 tbc (default)
Metadata:
handler_name : VideoHandler
另一种方法是保持命令原样，但先将其转换为 MKV，然后再转换为 MP4，即
ffmpeg -f concat -i concat.txt -c copy new_output.mkv
ffmpeg -i new_output.mkv -c copy new_output.mp4