On 6/23/2017 8:39 PM, Mark Thompson wrote: > With comments describing the derivation of each value. > --- > libavcodec/h264.h | 45 +++++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 45 insertions(+) > > diff --git a/libavcodec/h264.h b/libavcodec/h264.h > index eb3805c06..aa137b5b5 100644 > --- a/libavcodec/h264.h > +++ b/libavcodec/h264.h > @@ -44,4 +44,49 @@ enum { > H264_NAL_AUXILIARY_SLICE = 19, > }; > > + > +enum {
enum seems like a weird choice for this to be honest. Same with the following patch. What's wrong with using #define? > + // 7.4.2.1.1: seq_parameter_set_id is in [0, 31]. > + H264_MAX_SPS_COUNT = 32, > + // 7.4.2.2: pic_parameter_set_id is in [0, 255]. > + H264_MAX_PPS_COUNT = 256, > + > + // A.3: MaxDpbFrames is bounded above by 16. > + H264_MAX_DPB_FRAMES = 16, > + // 7.4.2.1.1: max_num_ref_frames is in [0, MaxDpbFrames], and > + // each reference frame can have two fields. > + H264_MAX_REFS = 2 * H264_MAX_DPB_FRAMES, > + > + // 7.4.3.1: modification_of_pic_nums_idc is not equal to 3 at most > + // num_ref_idx_lN_active_minus1 + 1 times (that is, once for each > + // possible reference), then equal to 3 once. > + H264_MAX_RPLM_COUNT = H264_MAX_REFS + 1, > + > + // 7.4.3.3: in the worst case, we begin with a full short-term > + // reference picture list. Each picture in turn is moved to the > + // long-term list (type 3) and then discarded from there (type 2). > + // Then, we set the length of the long-term list (type 4), mark > + // the current picture as long-term (type 6) and terminate the > + // process (type 0). > + H264_MAX_MMCO_COUNT = H264_MAX_REFS * 2 + 3, > + > + // A.2.1, A.2.3: profiles supporting FMO constrain > + // num_slice_groups_minus1 to be in [0, 7]. > + H264_MAX_SLICE_GROUPS = 8, > + > + // E.2.2: cpb_cnt_minus1 is in [0, 31]. > + H264_MAX_CPB_CNT = 32, > + > + // A.3: in table A-1 the highest level allows a MaxFS of 139264. > + H264_MAX_MB_PIC_SIZE = 139264, > + // A.3.1, A.3.2: PicWidthInMbs and PicHeightInMbs are constrained > + // to be not greater than sqrt(MaxFS * 8). Hence height/width are > + // bounded above by sqrt(139264 * 8) = 1055.5 macroblocks. > + H264_MAX_MB_WIDTH = 1055, > + H264_MAX_MB_HEIGHT = 1055, > + H264_MAX_WIDTH = H264_MAX_MB_WIDTH * 16, > + H264_MAX_HEIGHT = H264_MAX_MB_HEIGHT * 16, > +}; > + > + > #endif /* AVCODEC_H264_H */ > _______________________________________________ libav-devel mailing list libav-devel@libav.org https://lists.libav.org/mailman/listinfo/libav-devel