（文件夹范围）在 ffmpeg 中批量转换为 H264 编解码器

Question

So I was trying to get a hang of ffmpeg but I am not very good at it. I am trying to get all.mkv files converted to.m4v with a H264 codec. From another project I know that the h264_cuvid decoder worked perfectly well for my needs. I also checked via ffmpeg -decoders that I wrote it correctly. So the windows-batchfile (I frankenstein-ed together from other forums) looks like this:

for %%a in ("*.mkv") do ffmpeg -i "%%a" -c:v h264_cuvid -preset fast -crf 20 -b:v 128k "newfiles\%%~na.m4v"
pause

What I get is sadly only:

unknown encoder 'h264_cuvid'

How do I solve this?

If it is easier to start from scratch following is what I am trying to achieve

I am pretty new to this whole conversion/coding thing. I got a raspberry pi as a homeserver for my video files. Sadly it can only direct stream correctly encoded files (H.264), otherwise the Pi is trying to encode the videos itself (what causes buffering). So I am trying to find a solution to throw my whole library into a folder and convert it to a usable format.

Answer 1

I suggest you to use another codec because the h264_cuvid is strictly related to NVIDIA CUDA, and it doesn't run on Raspberri Pi of course. In order to use h264_cuvid, you need an NVIDIA GPU with the HW codec. See https://developer.nvidia.com/nvidia-video-codec-sdk/download for more informations.

Answer 2

Just re-mux if you can

Do the .mkv files already contain H.264 or another format supported by .m4v ? If yes, then you can just stream copy (re-mux) the video with -c:v copy and not have to re-encode:

for %%a in ("*.mkv") do ffmpeg -i "%%a" -c:v copy "newfiles\%%~na.m4v"
pause

---

h264_cuvid is a decoder

It is not an encoder, and Raspberry does not support CUVID anyway. See FFmpeg Wiki: Hardware .

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If you must encode

Use libx264

for %%a in ("*.mkv") do ffmpeg -i "%%a" -c:v libx264 -preset fast -crf 20 -b:v 128k "newfiles\%%~na.m4v"
pause

See FFmpeg Wiki: H.264 for more info.

Or h264_omx for hardware accelerated encoding

If your Raspberry and ffmpeg supports OpenMax you can use h264_omx:

for %%a in ("*.mkv") do ffmpeg -i "%%a" -c:v h264_omx "newfiles\%%~na.m4v"
pause

• You need your ffmpeg to be compiled with --enable-omx --enable-omx-rpi to use this.
• It is a simple and limited encoder compared to libx264 so results will not be as good.
• See FFmpeg hardware acceleration on Raspberry PI .

h264_mmal for hardware accelerated decoding

If your ffmpeg was compiled with --enable-mmal , and your Raspberry supports Broadcom Multi-Media Abstraction Layer, and your input video formats are either H.264, VC-1, MPEG-2, or MPEG-4, then you can also add hardware decoding:

for %%a in ("*.mkv") do ffmpeg -c:v h264_mmal -i "%%a" -c:v h264_omx "newfiles\%%~na.m4v"
pause