On Tue, Mar 6, 2018 at 3:51 PM, Eran Kornblau <eran.kornb...@kaltura.com> wrote: > Hi all, > > The attached patch adds a parameter that enables the user to choose which > AVC/HEVC NAL units to include in the output. > The parameter is supplied as a bitmask in order to keep things simple. > > A short background on why we need it - in our transcoding process, we > partition the video in chunks, the chunks are > transcoded in parallel and packaged in MPEG-TS container. The transcoded TS > chunks are then concatenated and > packaged in MP4. These MP4 files are later repackaged on-the-fly to various > protocols (HLS/DASH etc.) using our > JIT packager. > For performance reasons (can get into more detail if anyone's interested...), > when packaging the MP4 to DASH/CENC, > we configure the packager to assume that each AVC frame contains exactly one > NAL unit. > The problem is that the transition through MPEG-TS adds additional NAL units > (NAL AUD before each frame + SPS/PPS > before each key frame), and this assumption fails. > Using the attached patch we can pass '-nal_types_mask 0x3e' which will make > ffmpeg output only VCL NALs in the stream. >
Having such logic in one single muxer is not something we really like around here. Next time someone needs something similar for another codec, you're stuck re-implementing it. To achieve the same effect, Mark Thompson quickly wipped up a Bitstream Filter using his CBS framework which achieves the same result. He'll be sending that patch to the mailing list in a while. - Hendrik _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
