ffmpeg - 为什么 ffmpeg 试图同时生成 h.264 和 h.265？

Question

我想我只要求 h.265 输出，但下面的输出日志似乎表明它正在尝试生成 2 个视频流作为输出。

"C:\SOFTWARE\ffmpeg\0-homebuilt-x64\built_for_generic_opencl\x64_8bit\ffmpeg.exe" -hide_banner -v verbose  -threads 0 -i "G:\HDTV\0nvencc\test-mp4-03\ABC HD interlaced.aac.mp4" -t 15 -threads 0 -an  -sws_flags lanczos+accurate_rnd+full_chroma_int+full_chroma_inp -filter_complex "[0:v]yadif=0:0:0" -pixel_format yuv420p -pix_fmt yuv420p -strict -1 -f yuv4mpegpipe - 2> .\zzz1.h265.txt 
| "C:\SOFTWARE\ffmpeg\0-homebuilt-x64\built_for_generic_opencl\x64_8bit\ffmpeg.exe" -strict -1 -hide_banner -v verbose  -threads 0 -i - -strict -1 -c:v:0 libx265 -crf 28 output.mp4 -an  -y .\zzz.h265.mp4 2> .\zzz2.h265.txt 

-----------------------------
<snip to make code block smaller>
    Stream mapping:
      Stream #0:0 (h264) -> yadif
      yadif -> Stream #0:0 (wrapped_avframe)
    Press [q] to stop, [?] for help
    [h264 @ 000001b78ca87c00] Reinit context to 1920x1088, pix_fmt: yuv420p
    [graph 0 input from stream 0:0 @ 000001b78ca264c0] w:1920 h:1080 pixfmt:yuv420p tb:1/90000 fr:25/1 sar:1/1 sws_param:flags=2

Output file #0 (pipe:):
  Output stream #0:0 (video): 2 frames encoded; 2 packets muxed (1072 bytes); 
  Total: 2 packets (1072 bytes) muxed
Conversion failed!
-----------------------------
Routing option strict to both codec and muxer layer
    Last message repeated 1 times
Input #0, yuv4mpegpipe, from 'pipe:':
  Duration: N/A, start: 0.000000, bitrate: N/A
    Stream #0:0: Video: rawvideo, 1 reference frame (I420 / 0x30323449), yuv420p(progressive, left), 1920x1080, SAR 1:1 DAR 16:9, 25 fps, 25 tbr, 25 tbn, 25 tbc
Stream mapping:
  Stream #0:0 -> #0:0 (rawvideo (native) -> hevc (libx265))
  Stream #0:0 -> #1:0 (rawvideo (native) -> h264 (libx264))
[graph 0 input from stream 0:0 @ 0000027f5ebefa00] w:1920 h:1080 pixfmt:yuv420p tb:1/25 fr:25/1 sar:1/1 sws_param:flags=2
x265 [info]: HEVC encoder version 2.7+8-613d9f443769
x265 [info]: build info [Windows][GCC 7.3.0][64 bit] 8bit
x265 [info]: using cpu capabilities: MMX2 SSE2Fast SSSE3 SSE4.2 AVX
x265 [info]: Main profile, Level-4 (Main tier)
x265 [info]: Thread pool created using 8 threads
x265 [info]: Slices                              : 1
x265 [info]: frame threads / pool features       : 3 / wpp(17 rows)
-----------------------------

Answer 1

删除 output.mp4在 -crf 28 output.mp4 -an -y .\zzz.h265.mp4 2> .\zzz2.h265.txt