On 08/10/2024 09:31, Diederick C. Niehorster wrote:
Hi All,I am using ffmpeg for a library to interface with machine vision cameras that i am developing (not yet released),it allows storing the streams with really nice performance directly to, e.g., x264/mp4 (thanks ffmpeg!). For this, i am looking to support some new pixel formats as input formats in swscale. A first step for this would be to describe these formats in a AVPixFmtDescriptor. Example machine vision pixel formats are: Mono10p: 10-bit luma only: 4 pixels packed into 5 bytes (i.e., no padding) BayerRG10: 10-bit color components, in bayer patterns, 1 component put into 2 bytes (10 bits data+6 bits padding) BayerRG10p: 10-bit color components, in bayer pattern, 4 color components packed into 5 bytes (really the same packing as Mono10p). And also 12 bit variants. See https://www.1stvision.com/cameras/IDS/IDS-manuals/en/basics-monochrome-pixel-formats.html for a diagram of the Mono10p and https://www.1stvision.com/cameras/IDS/IDS-manuals/en/basics-raw-bayer-pixel-formats.html for diagrams of the packed and not packed bayer formats. I am wondering how to map these to AVPixFmtDescriptors. BayerRG10 is a problem: [AV_PIX_FMT_BAYER_RGGB10] = { .name = "bayer_rggb10", .nb_components = 3, .log2_chroma_w = 0, .log2_chroma_h = 0, .comp = { { 0, 2, 0, 0, ? }, { 0, 2, 0, 0, ? }, { 0, 2, 0, 0, ? }, }, .flags = AV_PIX_FMT_FLAG_RGB | AV_PIX_FMT_FLAG_BAYER, }, What should be put for the component depths? for 8bit bayer, 2,4,2 is used and for 16bit 4,8,4. This I guess signifies that for rggb 1/4 components is red or blue and 2/4 are green. By this logic, the values should be 2.5,5,2.5 for a ten-bit bayer format, which is not possible (12bit is possible, with 3,6,3). How could i handle this? For Mono10p (would be something like gray10p) BayerRG10p (would be something like bayer_rggb10p) my first question is: should this be encoded as bitstreams since their pixel values are not byte-aligned? Lastly, if i figure this out, is this something that might be considered for inclusion in ffmpeg, or is there a policy/strong opinions against these machine vision formats? All the best, Dee _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
We have support for AV_PIX_FMT_BAYER_RGGB16, since its a common Bayer layout that cinema cameras output, so its definitely within the scope and not some application-specific pixfmt.
RGGB10 is just a bitpacked version.Unfortunately, we do not directly support 10bit packed pixel formats, since we can't fit them into our definition, as we only support byte-aligned formats.
We treat those as codecs, for example AV_CODEC_ID_V210 and AV_CODEC_ID_BITPACKED.The format would have to be implemented as a codec, with a decoder that accepts AV_CODEC_ID_RGGB10 and outputs AV_PIX_FMT_RGGB16, setting
avctx->bits_per_sample to 10 to indicate how many bits are used.The decoder would simply call get_bits(10) and set each output pixel to the value it gets, nothing complex. You can see how
libavcodec/bitpacked_enc.c operates and use it as a template.
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