[FFmpeg-devel] [PATCH] avformat/avc: write the missing bits in the AVC Decoder Configuration Box

[James Almer]

Signed-off-by: James Almer <jamrial at gmail.com>
---
 libavformat/avc.c | 38 +++++++++++++++++++++++++++++++++-----
 libavformat/avc.h |  1 +
 2 files changed, 34 insertions(+), 5 deletions(-)

diff --git a/libavformat/avc.c b/libavformat/avc.c
index a041e84357..9bd215c07f 100644
--- a/libavformat/avc.c
+++ b/libavformat/avc.c
@@ -107,11 +107,11 @@ int ff_avc_parse_nal_units_buf(const uint8_t *buf_in, uint8_t **buf, int *size)
 
 int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
 {
-    AVIOContext *sps_pb = NULL, *pps_pb = NULL;
+    AVIOContext *sps_pb = NULL, *pps_pb = NULL, *sps_ext_pb = NULL;
     uint8_t *buf = NULL, *end, *start = NULL;
-    uint8_t *sps = NULL, *pps = NULL;
-    uint32_t sps_size = 0, pps_size = 0;
-    int ret, nb_sps = 0, nb_pps = 0;
+    uint8_t *sps = NULL, *pps = NULL, *sps_ext = NULL;
+    uint32_t sps_size = 0, pps_size = 0, sps_ext_size = 0;
+    int ret, nb_sps = 0, nb_pps = 0, nb_sps_ext = 0;
 
     if (len <= 6)
         return AVERROR_INVALIDDATA;
@@ -133,6 +133,9 @@ int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
     if (ret < 0)
         goto fail;
     ret = avio_open_dyn_buf(&pps_pb);
+    if (ret < 0)
+        goto fail;
+    ret = avio_open_dyn_buf(&sps_ext_pb);
     if (ret < 0)
         goto fail;
 
@@ -160,12 +163,21 @@ int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
             }
             avio_wb16(pps_pb, size);
             avio_write(pps_pb, buf, size);
+        } else if (nal_type == 13) { /* SPS_EXT */
+            nb_sps_ext++;
+            if (size > UINT16_MAX || nb_sps_ext >= 256) {
+                ret = AVERROR_INVALIDDATA;
+                goto fail;
+            }
+            avio_wb16(sps_ext_pb, size);
+            avio_write(sps_ext_pb, buf, size);
         }
 
         buf += size;
     }
     sps_size = avio_close_dyn_buf(sps_pb, &sps);
     pps_size = avio_close_dyn_buf(pps_pb, &pps);
+    sps_ext_size = avio_close_dyn_buf(sps_ext_pb, &sps_ext);
 
     if (sps_size < 6 || !pps_size) {
         ret = AVERROR_INVALIDDATA;
@@ -183,13 +195,29 @@ int ff_isom_write_avcc(AVIOContext *pb, const uint8_t *data, int len)
     avio_w8(pb, nb_pps); /* number of pps */
     avio_write(pb, pps, pps_size);
 
+    if (sps[3] != 66 && sps[3] != 77 && sps[3] != 88) {
+        H264SequenceParameterSet *seq = ff_avc_decode_sps(sps, sps_size);
+        if (!seq)
+            goto fail;
+        avio_w8(pb, 0xfc | seq->chroma_format_idc); /* 6 bits reserved (111111) + chroma_format_idc */
+        avio_w8(pb, 0xf8 | seq->bit_depth_luma - 8); /* 5 bits reserved (11111) + bit_depth_luma_minus8 */
+        avio_w8(pb, 0xf8 | seq->bit_depth_chroma - 8); /* 5 bits reserved (11111) + bit_depth_chroma_minus8 */
+        avio_w8(pb, nb_sps_ext); /* number of sps ext */
+        if (nb_sps_ext)
+            avio_write(pb, sps_ext, sps_ext_size);
+        av_free(seq);
+    }
+
 fail:
     if (!sps)
         avio_close_dyn_buf(sps_pb, &sps);
     if (!pps)
         avio_close_dyn_buf(pps_pb, &pps);
+    if (!sps_ext)
+        avio_close_dyn_buf(sps_ext_pb, &sps_ext);
     av_free(sps);
     av_free(pps);
+    av_free(sps_ext);
     av_free(start);
 
     return ret;
@@ -351,7 +379,7 @@ H264SequenceParameterSet *ff_avc_decode_sps(const uint8_t *buf, int buf_size)
             skip_bits1(&gb); // separate_colour_plane_flag
         }
         sps->bit_depth_luma = get_ue_golomb(&gb) + 8;
-        get_ue_golomb(&gb); // bit_depth_chroma_minus8
+        sps->bit_depth_chroma = get_ue_golomb(&gb) + 8;
         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++) {
diff --git a/libavformat/avc.h b/libavformat/avc.h
index a79bf9b2db..5286d19d89 100644
--- a/libavformat/avc.h
+++ b/libavformat/avc.h
@@ -43,6 +43,7 @@ typedef struct {
     uint8_t constraint_set_flags;
     uint8_t chroma_format_idc;
     uint8_t bit_depth_luma;
+    uint8_t bit_depth_chroma;
     uint8_t frame_mbs_only_flag;
     AVRational sar;
 } H264SequenceParameterSet;
-- 
2.24.0