ffmpeg-bitstream

To convert H.264 MP4 to Annex-B for HLS muxing without re-encoding, apply the h264_mp4toannexb bitstream filter with the -c copy flag in FFmpeg. This reframes AVCC to Annex-B, ensuring compatibility when multiplexing MP4/MOV into TS/HLS.

Yes, you can rewrite SPS/PPS or VPS headers without touching encoded video data by using FFmpeg bitstream filters. This modifies the header data like VUI parameters and AUD/SEI while keeping the underlying stream intact using -c copy.

The best way to extract or duplicate extradata as side-data for downstream tools is using the extract_extradata or dump_extra bitstream filters. This duplicates SPS/PPS side-data or dumps extradata before keyframes to keep segments joinable.

FFmpeg bitstream filtering works with HEVC and AV1 container transitions by applying specific filters like hevc_mp4toannexb. It modifies video and audio bitstreams without re-encoding to fix muxing errors across MP4/MOV to TS/HLS transitions.

You need the -c copy flag when applying bitstream filters to fix muxing errors because it prevents re-encoding. Bitstream filters like filter_units and setts modify headers and NAL-units directly, requiring -c copy to operate losslessly.

You should use the filter_units bitstream filter for NAL-unit filtering when you need to modify specific NAL-units without re-encoding. It enables targeted removal or rewriting of NAL-units to resolve container transition and compatibility issues.