avformat/mxfenc: support XAVC long gop

1 files changed, 186 insertions, 0 deletions

diff --git a/libavformat/avc.c b/libavformat/avc.c
index ec50033..a041e84 100644
--- a/libavformat/avc.c
+++ b/libavformat/avc.c
@@ -21,6 +21,7 @@
 
 #include "libavutil/intreadwrite.h"
 #include "libavcodec/h264.h"
+#include "libavcodec/get_bits.h"
 #include "avformat.h"
 #include "avio.h"
 #include "avc.h"
@@ -241,3 +242,188 @@ const uint8_t *ff_avc_mp4_find_startcode(const uint8_t *start,
 
     return start + res;
 }
+
+uint8_t *ff_nal_unit_extract_rbsp(const uint8_t *src, uint32_t src_len,
+                                  uint32_t *dst_len, int header_len)
+{
+    uint8_t *dst;
+    uint32_t i, len;
+
+    dst = av_malloc(src_len + AV_INPUT_BUFFER_PADDING_SIZE);
+    if (!dst)
+        return NULL;
+
+    /* NAL unit header */
+    i = len = 0;
+    while (i < header_len && i < src_len)
+        dst[len++] = src[i++];
+
+    while (i + 2 < src_len)
+        if (!src[i] && !src[i + 1] && src[i + 2] == 3) {
+            dst[len++] = src[i++];
+            dst[len++] = src[i++];
+            i++; // remove emulation_prevention_three_byte
+        } else
+            dst[len++] = src[i++];
+
+    while (i < src_len)
+        dst[len++] = src[i++];
+
+    memset(dst + len, 0, AV_INPUT_BUFFER_PADDING_SIZE);
+
+    *dst_len = len;
+    return dst;
+}
+
+static const AVRational avc_sample_aspect_ratio[17] = {
+    {   0,  1 },
+    {   1,  1 },
+    {  12, 11 },
+    {  10, 11 },
+    {  16, 11 },
+    {  40, 33 },
+    {  24, 11 },
+    {  20, 11 },
+    {  32, 11 },
+    {  80, 33 },
+    {  18, 11 },
+    {  15, 11 },
+    {  64, 33 },
+    { 160, 99 },
+    {   4,  3 },
+    {   3,  2 },
+    {   2,  1 },
+};
+
+static inline int get_ue_golomb(GetBitContext *gb) {
+    int i;
+    for (i = 0; i < 32 && !get_bits1(gb); i++)
+        ;
+    return get_bitsz(gb, i) + (1 << i) - 1;
+}
+
+static inline int get_se_golomb(GetBitContext *gb) {
+    int v = get_ue_golomb(gb) + 1;
+    int sign = -(v & 1);
+    return ((v >> 1) ^ sign) - sign;
+}
+
+H264SequenceParameterSet *ff_avc_decode_sps(const uint8_t *buf, int buf_size)
+{
+    int i, j, ret, rbsp_size, aspect_ratio_idc, pic_order_cnt_type;
+    int num_ref_frames_in_pic_order_cnt_cycle;
+    int delta_scale, lastScale = 8, nextScale = 8;
+    int sizeOfScalingList;
+    H264SequenceParameterSet *sps = NULL;
+    GetBitContext gb;
+    uint8_t *rbsp_buf;
+
+    rbsp_buf = ff_nal_unit_extract_rbsp(buf, buf_size, &rbsp_size, 0);
+    if (!rbsp_buf)
+        return NULL;
+
+    ret = init_get_bits8(&gb, rbsp_buf, rbsp_size);
+    if (ret < 0)
+        goto end;
+
+    sps = av_mallocz(sizeof(*sps));
+    if (!sps)
+        goto end;
+
+    sps->profile_idc = get_bits(&gb, 8);
+    sps->constraint_set_flags |= get_bits1(&gb) << 0; // constraint_set0_flag
+    sps->constraint_set_flags |= get_bits1(&gb) << 1; // constraint_set1_flag
+    sps->constraint_set_flags |= get_bits1(&gb) << 2; // constraint_set2_flag
+    sps->constraint_set_flags |= get_bits1(&gb) << 3; // constraint_set3_flag
+    sps->constraint_set_flags |= get_bits1(&gb) << 4; // constraint_set4_flag
+    sps->constraint_set_flags |= get_bits1(&gb) << 5; // constraint_set5_flag
+    skip_bits(&gb, 2); // reserved_zero_2bits
+    sps->level_idc = get_bits(&gb, 8);
+    sps->id = get_ue_golomb(&gb);
+
+    if (sps->profile_idc == 100 || sps->profile_idc == 110 ||
+        sps->profile_idc == 122 || sps->profile_idc == 244 || sps->profile_idc ==  44 ||
+        sps->profile_idc ==  83 || sps->profile_idc ==  86 || sps->profile_idc == 118 ||
+        sps->profile_idc == 128 || sps->profile_idc == 138 || sps->profile_idc == 139 ||
+        sps->profile_idc == 134) {
+        sps->chroma_format_idc = get_ue_golomb(&gb); // chroma_format_idc
+        if (sps->chroma_format_idc == 3) {
+            skip_bits1(&gb); // separate_colour_plane_flag
+        }
+        sps->bit_depth_luma = get_ue_golomb(&gb) + 8;
+        get_ue_golomb(&gb); // bit_depth_chroma_minus8
+        skip_bits1(&gb); // qpprime_y_zero_transform_bypass_flag
+        if (get_bits1(&gb)) { // seq_scaling_matrix_present_flag
+            for (i = 0; i < ((sps->chroma_format_idc != 3) ? 8 : 12); i++) {
+                if (!get_bits1(&gb)) // seq_scaling_list_present_flag
+                    continue;
+                lastScale = 8;
+                nextScale = 8;
+                sizeOfScalingList = i < 6 ? 16 : 64;
+                for (j = 0; j < sizeOfScalingList; j++) {
+                    if (nextScale != 0) {
+                        delta_scale = get_se_golomb(&gb);
+                        nextScale = (lastScale + delta_scale) & 0xff;
+                    }
+                    lastScale = nextScale == 0 ? lastScale : nextScale;
+                }
+            }
+        }
+    } else {
+        sps->chroma_format_idc = 1;
+        sps->bit_depth_luma = 8;
+    }
+
+    get_ue_golomb(&gb); // log2_max_frame_num_minus4
+    pic_order_cnt_type = get_ue_golomb(&gb);
+
+    if (pic_order_cnt_type == 0) {
+        get_ue_golomb(&gb); // log2_max_pic_order_cnt_lsb_minus4
+    } else if (pic_order_cnt_type == 1) {
+        skip_bits1(&gb);    // delta_pic_order_always_zero
+        get_se_golomb(&gb); // offset_for_non_ref_pic
+        get_se_golomb(&gb); // offset_for_top_to_bottom_field
+        num_ref_frames_in_pic_order_cnt_cycle = get_ue_golomb(&gb);
+        for (i = 0; i < num_ref_frames_in_pic_order_cnt_cycle; i++)
+            get_se_golomb(&gb); // offset_for_ref_frame
+    }
+
+    get_ue_golomb(&gb); // max_num_ref_frames
+    skip_bits1(&gb); // gaps_in_frame_num_value_allowed_flag
+    get_ue_golomb(&gb); // pic_width_in_mbs_minus1
+    get_ue_golomb(&gb); // pic_height_in_map_units_minus1
+
+    sps->frame_mbs_only_flag = get_bits1(&gb);
+    if (!sps->frame_mbs_only_flag)
+        skip_bits1(&gb); // mb_adaptive_frame_field_flag
+
+    skip_bits1(&gb); // direct_8x8_inference_flag
+
+    if (get_bits1(&gb)) { // frame_cropping_flag
+        get_ue_golomb(&gb); // frame_crop_left_offset
+        get_ue_golomb(&gb); // frame_crop_right_offset
+        get_ue_golomb(&gb); // frame_crop_top_offset
+        get_ue_golomb(&gb); // frame_crop_bottom_offset
+    }
+
+    if (get_bits1(&gb)) { // vui_parameters_present_flag
+        if (get_bits1(&gb)) { // aspect_ratio_info_present_flag
+            aspect_ratio_idc = get_bits(&gb, 8);
+            if (aspect_ratio_idc == 0xff) {
+                sps->sar.num = get_bits(&gb, 16);
+                sps->sar.den = get_bits(&gb, 16);
+            } else if (aspect_ratio_idc < FF_ARRAY_ELEMS(avc_sample_aspect_ratio)) {
+                sps->sar = avc_sample_aspect_ratio[aspect_ratio_idc];
+            }
+        }
+    }
+
+    if (!sps->sar.den) {
+        sps->sar.num = 1;
+        sps->sar.den = 1;
+    }
+
+ end:
+    av_free(rbsp_buf);
+    return sps;
+}