我有两个单独的 FFmpeg 命令，每个命令都可以很好地运行，一个用于捕获视频，另一个用于从同一设备捕获音频；捕获的音频是：
ffmpeg -f alsa -thread_queue_size 16384 -i hw:CARD=C4K,DEV=0 -acodec aac /home/pi/Videos/temp.wav
捕获的视频是：
ffmpeg -y -nostdin -f v4l2 -threads auto -input_format yuyv422 -fflags +genpts -flags +global_header -thread_queue_size 16384 -i /dev/video0 -s 1280x720 -r 25 -vcodec h264_v4l2m2m -num_output_buffers 32 -num_capture_buffers 16 -keyint_min 25 -force_key_frames "expr:gte(t,n_forced*1)" -g 50 -b:v 6M -pix_fmt nv12 -f mpegts -muxdelay 0 -muxpreload 0 -movflags +faststart /home/pi/Videos/output.mp4
我曾尝试将两者结合到一个调用中以生成一个带有音频通道的视频文件，但是无论我怎么尝试，结果输出都一团糟；显然，我遗漏了一些东西，例如，我最近的尝试用音频通道制作了一个冻结的图像视频：
ffmpeg -y -nostdin -f v4l2 -threads auto -input_format yuyv422 -fflags +genpts -flags +global_header -thread_queue_size 16384 -i /dev/video0 -f alsa -thread_queue_size 16384 -i hw:CARD=C4K,DEV=0 -acodec aac -s 1280x720 -r 25 -vcodec h264_v4l2m2m -num_output_buffers 32 -num_capture_buffers 16 -keyint_min 25 -force_key_frames "expr:gte(t,n_forced*1)" -g 50 -b:v 6M -b:a 128K -pix_fmt nv12 -f mpegts -muxdelay 0 -muxpreload 0 -movflags +faststart /home/pi/Videos/output.mp4 -loglevel debug
上述命令的完整输出：
ffmpeg version ca55240 Copyright (c) 2000-2020 the FFmpeg developers
built with gcc 8 (Debian 8.3.0-6)
configuration: --prefix=/home/pi/ffmpeg_build --pkg-config-flags='pkg-config --static' --extra-cflags=-I/home/pi/ffmpeg_build/include --extra-ldflags=-L/home/pi/ffmpeg_build/lib --extra-libs='-lpthread -lm' --bindir=/home/pi/bin --enable-gpl --enable-gnutls --disable-libaom --enable-libass --enable-libfdk-aac --enable-libfreetype --enable-libmp3lame --enable-libopus --enable-libvorbis --enable-libvpx --enable-libx264 --disable-libx265 --enable-nonfree --arch=aarch64 --disable-libxml2 --enable-libwebp --enable-libdrm
libavutil 56. 51.100 / 56. 51.100
libavcodec 58. 91.100 / 58. 91.100
libavformat 58. 45.100 / 58. 45.100
libavdevice 58. 10.100 / 58. 10.100
libavfilter 7. 85.100 / 7. 85.100
libswscale 5. 7.100 / 5. 7.100
libswresample 3. 7.100 / 3. 7.100
libpostproc 55. 7.100 / 55. 7.100
Splitting the commandline.
Reading option '-y' ... matched as option 'y' (overwrite output files) with argument '1'.
Reading option '-nostdin' ... matched as option 'stdin' (enable or disable interaction on standard input) with argument 0.
Reading option '-f' ... matched as option 'f' (force format) with argument 'v4l2'.
Reading option '-threads' ... matched as AVOption 'threads' with argument 'auto'.
Reading option '-input_format' ... matched as AVOption 'input_format' with argument 'yuyv422'.
Reading option '-fflags' ... matched as AVOption 'fflags' with argument '+genpts'.
Reading option '-flags' ... matched as AVOption 'flags' with argument '+global_header'.
Reading option '-thread_queue_size' ... matched as option 'thread_queue_size' (set the maximum number of queued packets from the demuxer) with argument '16384'.
Reading option '-i' ... matched as input url with argument '/dev/video0'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'alsa'.
Reading option '-thread_queue_size' ... matched as option 'thread_queue_size' (set the maximum number of queued packets from the demuxer) with argument '16384'.
Reading option '-i' ... matched as input url with argument 'hw:CARD=C4K,DEV=0'.
Reading option '-acodec' ... matched as option 'acodec' (force audio codec ('copy' to copy stream)) with argument 'aac'.
Reading option '-s' ... matched as option 's' (set frame size (WxH or abbreviation)) with argument '1280x720'.
Reading option '-r' ... matched as option 'r' (set frame rate (Hz value, fraction or abbreviation)) with argument '25'.
Reading option '-vcodec' ... matched as option 'vcodec' (force video codec ('copy' to copy stream)) with argument 'h264_v4l2m2m'.
Reading option '-num_output_buffers' ... matched as AVOption 'num_output_buffers' with argument '32'.
Reading option '-num_capture_buffers' ... matched as AVOption 'num_capture_buffers' with argument '16'.
Reading option '-keyint_min' ... matched as AVOption 'keyint_min' with argument '25'.
Reading option '-force_key_frames' ... matched as option 'force_key_frames' (force key frames at specified timestamps) with argument 'expr:gte(t,n_forced*1)'.
Reading option '-g' ... matched as AVOption 'g' with argument '50'.
Reading option '-b:v' ... matched as option 'b' (video bitrate (please use -b:v)) with argument '6M'.
Reading option '-b:a' ... matched as option 'b' (video bitrate (please use -b:v)) with argument '128K'.
Reading option '-pix_fmt' ... matched as option 'pix_fmt' (set pixel format) with argument 'nv12'.
Reading option '-f' ... matched as option 'f' (force format) with argument 'mpegts'.
Reading option '-muxdelay' ... matched as option 'muxdelay' (set the maximum demux-decode delay) with argument '0'.
Reading option '-muxpreload' ... matched as option 'muxpreload' (set the initial demux-decode delay) with argument '0'.
Reading option '-movflags' ... matched as AVOption 'movflags' with argument '+faststart'.
Reading option '/home/pi/Videos/output.mp4' ... matched as output url.
Reading option '-loglevel' ... matched as option 'loglevel' (set logging level) with argument 'debug'.
Finished splitting the commandline.
Parsing a group of options: global .
Applying option y (overwrite output files) with argument 1.
Applying option nostdin (enable or disable interaction on standard input) with argument 0.
Applying option loglevel (set logging level) with argument debug.
Successfully parsed a group of options.
Parsing a group of options: input url /dev/video0.
Applying option f (force format) with argument v4l2.
Applying option thread_queue_size (set the maximum number of queued packets from the demuxer) with argument 16384.
Successfully parsed a group of options.
Opening an input file: /dev/video0.
[video4linux2,v4l2 @ 0x55a0c86b40] fd:3 capabilities:84a00001
[video4linux2,v4l2 @ 0x55a0c86b40] Current input_channel: 0, input_name: Input 1, input_std: 0
[video4linux2,v4l2 @ 0x55a0c86b40] Querying the device for the current frame size
[video4linux2,v4l2 @ 0x55a0c86b40] Setting frame size to 1920x1080
[video4linux2,v4l2 @ 0x55a0c86b40] Dequeued v4l2 buffer contains corrupted data (0 bytes).
[video4linux2,v4l2 @ 0x55a0c86b40] All info found Input #0, video4linux2,v4l2, from '/dev/video0':
Duration: N/A, start: 0.000000, bitrate: 1988671 kb/s
Stream #0:0, 1, 1/1000000: Video: rawvideo, 1 reference frame (YUY2 / 0x32595559), yuyv422, 1920x1080, 0/1, 1988671 kb/s, 59.94 fps, 59.94 tbr, 1000k tbn, 1000k tbc Successfully opened the file.
Parsing a group of options: input url hw:CARD=C4K,DEV=0.
Applying option f (force format) with argument alsa.
Applying option thread_queue_size (set the maximum number of queued packets from the demuxer) with argument 16384.
Successfully parsed a group of options.
Opening an input file: hw:CARD=C4K,DEV=0.
[alsa @ 0x55a0c89630] All info found
Guessed Channel Layout for Input Stream #1.0 : stereo Input #1, alsa, from 'hw:CARD=C4K,DEV=0':
Duration: N/A, start: 1608286705.387903, bitrate: 1536 kb/s
Stream #1:0, 1, 1/1000000: Audio: pcm_s16le, 48000 Hz, stereo, s16, 1536 kb/s Successfully opened the file.
Parsing a group of options: output url /home/pi/Videos/output.mp4.
Applying option acodec (force audio codec ('copy' to copy stream)) with argument aac.
Applying option s (set frame size (WxH or abbreviation)) with argument 1280x720.
Applying option r (set frame rate (Hz value, fraction or abbreviation)) with argument 25.
Applying option vcodec (force video codec ('copy' to copy stream)) with argument h264_v4l2m2m.
Applying option force_key_frames (force key frames at specified timestamps) with argument expr:gte(t,n_forced*1).
Applying option b:v (video bitrate (please use -b:v)) with argument 6M.
Applying option b:a (video bitrate (please use -b:v)) with argument 128K.
Applying option pix_fmt (set pixel format) with argument nv12.
Applying option f (force format) with argument mpegts.
Applying option muxdelay (set the maximum demux-decode delay) with argument 0.
Applying option muxpreload (set the initial demux-decode delay) with argument 0.
Successfully parsed a group of options.
Opening an output file: /home/pi/Videos/output.mp4.
[file @ 0x55a0ca7210] Setting default whitelist 'file,crypto,data'
Successfully opened the file.
Stream mapping:
Stream #0:0 -> #0:0 (rawvideo (native) -> h264 (h264_v4l2m2m))
Stream #1:0 -> #0:1 (pcm_s16le (native) -> aac (native)) cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
Last message repeated 3 times
[video4linux2,v4l2 @ 0x55a0c86b40] Dequeued v4l2 buffer contains corrupted data (0 bytes).
cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
Last message repeated 12 times
[video4linux2,v4l2 @ 0x55a0c86b40] Dequeued v4l2 buffer contains corrupted data (0 bytes).
cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
[video4linux2,v4l2 @ 0x55a0c86b40] Dequeued v4l2 buffer contains corrupted data (0 bytes).
cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
[video4linux2,v4l2 @ 0x55a0c86b40] Dequeued v4l2 buffer contains corrupted data (0 bytes).
cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
[video4linux2,v4l2 @ 0x55a0c86b40] Dequeued v4l2 buffer contains corrupted data (0 bytes).
Last message repeated 2 times
cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
[video4linux2,v4l2 @ 0x55a0c86b40] Dequeued v4l2 buffer contains corrupted data (0 bytes).
Last message repeated 23 times
cur_dts is invalid st:0 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
Last message repeated 1452 times
[rawvideo @ 0x55a0c89130] PACKET SIZE: 4147200, STRIDE: 3840 detected 4 logical cores [graph 0 input from stream 0:0 @ 0x55a0ca9080] Setting 'video_size' to value '1920x1080'
[graph 0 input from stream 0:0 @ 0x55a0ca9080] Setting 'pix_fmt' to value '1'
[graph 0 input from stream 0:0 @ 0x55a0ca9080] Setting 'time_base' to value '1/1000000'
[graph 0 input from stream 0:0 @ 0x55a0ca9080] Setting 'pixel_aspect' to value '0/1'
[graph 0 input from stream 0:0 @ 0x55a0ca9080] Setting 'frame_rate' to value '7013/117'
[graph 0 input from stream 0:0 @ 0x55a0ca9080] w:1920 h:1080 pixfmt:yuyv422 tb:1/1000000 fr:7013/117 sar:0/1
[scaler_out_0_0 @ 0x55a0cb0060] Setting 'w' to value '1280'
[scaler_out_0_0 @ 0x55a0cb0060] Setting 'h' to value '720'
[scaler_out_0_0 @ 0x55a0cb0060] Setting 'flags' to value 'bicubic'
[scaler_out_0_0 @ 0x55a0cb0060] w:1280 h:720 flags:'bicubic' interl:0 [format @ 0x55a0cb05b0] Setting 'pix_fmts' to value 'nv12'
[AVFilterGraph @ 0x55a0ca2730] query_formats: 5 queried, 4 merged, 0 already done, 0 delayed
[scaler_out_0_0 @ 0x55a0cb0060] w:1920 h:1080 fmt:yuyv422 sar:0/1 -> w:1280 h:720 fmt:nv12 sar:0/1 flags:0x4 [h264_v4l2m2m @ 0x55a0ca5610] probing device /dev/video12 [h264_v4l2m2m @ 0x55a0ca5610] driver 'bcm2835-codec' on card 'bcm2835-codec-isp' in mplane mode [h264_v4l2m2m @ 0x55a0ca5610] v4l2 capture format not supported [h264_v4l2m2m @ 0x55a0ca5610] probing device /dev/video11 [h264_v4l2m2m @ 0x55a0ca5610] driver 'bcm2835-codec' on card 'bcm2835-codec-encode' in mplane mode [h264_v4l2m2m @ 0x55a0ca5610] Using device /dev/video11 [h264_v4l2m2m @ 0x55a0ca5610] driver 'bcm2835-codec' on card 'bcm2835-codec-encode' in mplane mode [h264_v4l2m2m @ 0x55a0ca5610] requesting formats: output=NV12 capture=H264 [h264_v4l2m2m @ 0x55a0ca5610] output: NV12 32 buffers initialized: 1280x0720, sizeimage 01382400, bytesperline 00001280 [h264_v4l2m2m @ 0x55a0ca5610] capture: H264 16 buffers initialized: 1280x0720, sizeimage 00524288, bytesperline 00000000 [h264_v4l2m2m @ 0x55a0ca5610] Failed to set number of B-frames: Invalid argument [h264_v4l2m2m @ 0x55a0ca5610] Failed to get number of B-frames [h264_v4l2m2m @ 0x55a0ca5610] Failed to set header mode: Invalid argument [h264_v4l2m2m @ 0x55a0ca5610] Encoder: bit rate = 6000000 [h264_v4l2m2m @ 0x55a0ca5610] Failed to set frame level rate control: Invalid argument [h264_v4l2m2m @ 0x55a0ca5610] Failed to set gop size: Invalid argument [h264_v4l2m2m @ 0x55a0ca5610] Encoder: repeat parameter sets = 1 [h264_v4l2m2m @ 0x55a0ca5610] Encoder Context: id (27), profile (-99), frame rate(25/1), number b-frames (0), gop size (50), bit rate (6000000), qmin (-1), qmax (-1) [h264_v4l2m2m @ 0x55a0ca5610] Failed to set minimum video quantizer scale: Invalid argument [h264_v4l2m2m @ 0x55a0ca5610] Failed to set maximum video quantizer scale: Invalid argument Forced keyframe at time 0.000000 [h264_v4l2m2m @ 0x55a0ca5610] Encoder: force key frame = 0 cur_dts is invalid st:0 (0) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream) cur_dts is invalid st:1 (0) [init:0 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
[graph_1_in_1_0 @ 0x55a0d465d0] Setting 'time_base' to value '1/48000'
[graph_1_in_1_0 @ 0x55a0d465d0] Setting 'sample_rate' to value '48000'
[graph_1_in_1_0 @ 0x55a0d465d0] Setting 'sample_fmt' to value 's16'
[graph_1_in_1_0 @ 0x55a0d465d0] Setting 'channel_layout' to value '0x3'
[graph_1_in_1_0 @ 0x55a0d465d0] tb:1/48000 samplefmt:s16 samplerate:48000 chlayout:0x3
[format_out_0_1 @ 0x55a0d46af0] Setting 'sample_fmts' to value 'fltp'
[format_out_0_1 @ 0x55a0d46af0] Setting 'sample_rates' to value '96000|88200|64000|48000|44100|32000|24000|22050|16000|12000|11025|8000|7350'
[format_out_0_1 @ 0x55a0d46af0] auto-inserting filter 'auto_resampler_0' between the filter 'Parsed_anull_0' and the filter 'format_out_0_1'
[AVFilterGraph @ 0x55a0d45c10] query_formats: 4 queried, 6 merged, 3 already done, 0 delayed
[auto_resampler_0 @ 0x55a0d47740] [SWR @ 0x55a0d47890] Using s16p internally between filters
[auto_resampler_0 @ 0x55a0d47740] ch:2 chl:stereo fmt:s16 r:48000Hz -> ch:2 chl:stereo fmt:fltp r:48000Hz [mpegts @ 0x55a0caec00] service 1 using PCR in pid=256, pcr_period=80ms [mpegts @ 0x55a0caec00] muxrate VBR, sdt every 500 ms, pat/pmt every 100 ms Output #0, mpegts, to '/home/pi/Videos/output.mp4':
Metadata:
encoder : Lavf58.45.100
Stream #0:0, 0, 1/90000: Video: h264 (h264_v4l2m2m), 1 reference frame, nv12(progressive), 1280x720, 0/1, q=-1--1, 6000 kb/s, 25 fps, 90k tbn, 25 tbc
Metadata:
encoder : Lavc58.91.100 h264_v4l2m2m
Stream #0:1, 0, 1/90000: Audio: aac (LC), 48000 Hz, stereo, fltp, delay 1024, 128 kb/s
Metadata:
encoder : Lavc58.91.100 aac
cur_dts is invalid st:0 (0) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream) cur_dts is invalid st:1 (0) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream) [rawvideo @ 0x55a0c89130] PACKET SIZE: 4147200, STRIDE: 3840 Clipping frame in rate conversion by 0.132942 cur_dts is invalid st:1 (0) [init:1 i_done:0 finish:0] (this is harmless if it occurs once at the start per stream)
Last message repeated 17 times
^Cframe= 2 fps=0.3 q=-0.0 Lsize= 183kB time=00:21:16.64 bitrate= 1.2kbits/s speed= 189x
video:24kB audio:101kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: 46.992252% Input file #0 (/dev/video0):
Input stream #0:0 (video): 34 packets read (8294400 bytes); 2 frames decoded;
Total: 34 packets (8294400 bytes) demuxed Input file #1 (hw:CARD=C4K,DEV=0):
Input stream #1:0 (audio): 2712 packets read (1233148 bytes); 2712 frames decoded (308287 samples);
Total: 2712 packets (1233148 bytes) demuxed Output file #0 (/home/pi/Videos/output.mp4):
Output stream #0:0 (video): 2 frames encoded; 2 packets muxed (24588 bytes);
Output stream #0:1 (audio): 301 frames encoded (308224 samples); 302 packets muxed (103182 bytes);
Total: 304 packets (127770 bytes) muxed
2714 frames successfully decoded, 0 decoding errors [AVIOContext @ 0x55a0ca7100] Statistics: 0 seeks, 1 writeouts [aac @ 0x55a0ca65e0] Qavg: 165.061 Exiting normally, received signal 2.
谁能帮我解决这个问题？
非常感谢！
RS