Bitstream filter support for A/53 Closed Captions

doc/bitstream_filters.texi

@@ -243,6 +243,17 @@ ffmpeg -i hapqa_inputfile.mov -c copy -bsf:v hapqa_extract=texture=alpha -tag:v
 Modify metadata embedded in an H.264 stream.
 
 @table @option
+@item a53_cc
+Insert or remove registered userdata SEI NAL units containing A/53 closed captions.
+
+@table @samp
+@item pass
+@item insert
+@item remove
+@end table
+
+Default is pass.
+
 @item aud
 Insert or remove AUD NAL units in all access units of the stream.
 
@@ -387,6 +398,17 @@ confuse other transformations which require correct extradata.
 Modify metadata embedded in an HEVC stream.
 
 @table @option
+@item a53_cc
+Insert or remove registered userdata SEI NAL units containing A/53 closed captions.
+
+@table @samp
+@item pass
+@item insert
+@item remove
+@end table
+
+Default is pass.
+
 @item aud
 Insert or remove AUD NAL units in all access units of the stream.
 
@@ -537,6 +559,17 @@ Decompress non-standard compressed MP3 audio headers.
 Modify metadata embedded in an MPEG-2 stream.
 
 @table @option
+@item a53_cc
+Insert or remove user data containing A/53 closed captions.
+
+@table @samp
+@item pass
+@item insert
+@item remove
+@end table
+
+Default is pass.
+
 @item display_aspect_ratio
 Set the display aspect ratio in the stream.
 

libavcodec/Makefile

@@ -1212,12 +1212,12 @@ OBJS-$(CONFIG_EXTRACT_EXTRADATA_BSF)      += extract_extradata_bsf.o    \
                                              av1_parse.o h2645_parse.o
 OBJS-$(CONFIG_FILTER_UNITS_BSF)           += filter_units_bsf.o
 OBJS-$(CONFIG_H264_METADATA_BSF)          += h264_metadata_bsf.o h264_levels.o \
-                                             h2645data.o
+                                             h2645data.o cbs_misc.o
 OBJS-$(CONFIG_H264_MP4TOANNEXB_BSF)       += h264_mp4toannexb_bsf.o
 OBJS-$(CONFIG_H264_REDUNDANT_PPS_BSF)     += h264_redundant_pps_bsf.o
 OBJS-$(CONFIG_HAPQA_EXTRACT_BSF)          += hapqa_extract_bsf.o hap.o
 OBJS-$(CONFIG_HEVC_METADATA_BSF)          += h265_metadata_bsf.o h265_profile_level.o \
-                                             h2645data.o
+                                             h2645data.o cbs_misc.o
 OBJS-$(CONFIG_HEVC_MP4TOANNEXB_BSF)       += hevc_mp4toannexb_bsf.o
 OBJS-$(CONFIG_IMX_DUMP_HEADER_BSF)        += imx_dump_header_bsf.o
 OBJS-$(CONFIG_MEDIA100_TO_MJPEGB_BSF)     += media100_to_mjpegb_bsf.o
@@ -1227,7 +1227,7 @@ OBJS-$(CONFIG_MPEG4_UNPACK_BFRAMES_BSF)   += mpeg4_unpack_bframes_bsf.o
 OBJS-$(CONFIG_MOV2TEXTSUB_BSF)            += movsub_bsf.o
 OBJS-$(CONFIG_MP3_HEADER_DECOMPRESS_BSF)  += mp3_header_decompress_bsf.o \
                                              mpegaudiotabs.o
-OBJS-$(CONFIG_MPEG2_METADATA_BSF)         += mpeg2_metadata_bsf.o
+OBJS-$(CONFIG_MPEG2_METADATA_BSF)         += mpeg2_metadata_bsf.o cbs_misc.o
 OBJS-$(CONFIG_NOISE_BSF)                  += noise_bsf.o
 OBJS-$(CONFIG_NULL_BSF)                   += null_bsf.o
 OBJS-$(CONFIG_OPUS_METADATA_BSF)          += opus_metadata_bsf.o

libavcodec/cbs_misc.c

@@ -0,0 +1,217 @@
+/*
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "libavutil/attributes.h"
+#include "libavutil/avassert.h"
+
+#include "cbs.h"
+#include "cbs_internal.h"
+#include "cbs_misc.h"
+
+#define CHECK(call) do { \
+        err = (call); \
+        if (err < 0) \
+            return err; \
+    } while (0)
+
+#define FUNC_NAME(rw, codec, name) cbs_ ## codec ## _ ## rw ## _ ## name
+#define FUNC_MISC(rw, name) FUNC_NAME(rw, misc, name)
+#define FUNC(name) FUNC_MISC(READWRITE, name)
+
+
+#define READWRITE read
+#define RWContext GetBitContext
+
+#define xui(width, name, var) do { \
+        uint32_t value = 0; \
+        CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, NULL, \
+                                   &value, 0, MAX_UINT_BITS(width))); \
+        var = value; \
+    } while (0)
+
+#define ui(width, name) \
+        xui(width, name, current->name)
+
+#define fixed(width, name, expected) do { \
+        av_unused uint32_t value; \
+        CHECK(ff_cbs_read_unsigned(ctx, rw, width, #name, NULL, \
+                                   &value, expected, expected)); \
+    } while (0)
+
+#include "cbs_misc_syntax_template.c"
+
+#undef READWRITE
+#undef RWContext
+#undef xui
+#undef ui
+#undef fixed
+
+
+#define READWRITE write
+#define RWContext PutBitContext
+
+#define xui(width, name, var) do { \
+        CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, NULL, \
+                                    var, 0, MAX_UINT_BITS(width))); \
+    } while (0)
+
+#define ui(width, name) \
+        xui(width, name, current->name)
+
+#define fixed(width, name, value) do { \
+        CHECK(ff_cbs_write_unsigned(ctx, rw, width, #name, NULL, \
+                                    value, value, value)); \
+    } while (0)
+
+#include "cbs_misc_syntax_template.c"
+
+#undef READWRITE
+#undef RWContext
+#undef xui
+#undef ui
+#undef fixed
+
+
+int ff_cbs_read_a53_user_data(CodedBitstreamContext *ctx,
+                              A53UserData *data,
+                              const uint8_t *read_buffer, size_t length)
+{
+    GetBitContext gbc;
+    int err;
+
+    err = init_get_bits(&gbc, read_buffer, 8 * length);
+    if (err < 0)
+        return err;
+
+    return cbs_misc_read_a53_user_data(ctx, &gbc, data);
+}
+
+int ff_cbs_write_a53_user_data(CodedBitstreamContext *ctx,
+                               uint8_t *write_buffer, size_t *length,
+                               A53UserData *data)
+{
+    PutBitContext pbc;
+    int err;
+
+    init_put_bits(&pbc, write_buffer, *length);
+
+    err = cbs_misc_write_a53_user_data(ctx, &pbc, data);
+    if (err < 0) {
+        // Includes AVERROR(ENOSPC).
+        return err;
+    }
+
+    // That output must be aligned.
+    av_assert0(put_bits_count(&pbc) % 8 == 0);
+
+    *length = put_bits_count(&pbc) / 8;
+
+    flush_put_bits(&pbc);
+
+    return 0;
+}
+
+int ff_cbs_read_a53_cc_side_data(CodedBitstreamContext *ctx,
+                                 A53UserData *data,
+                                 const uint8_t *side_data,
+                                 size_t side_data_size)
+{
+    GetBitContext gbc;
+    CEA708CCData *cc;
+    int err, i, cc_count;
+
+    if (side_data_size % 3) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "A53 CC side data length must "
+               "be a multiple of 3 (got %zu).\n", side_data_size);
+        return AVERROR(EINVAL);
+    }
+    cc_count = side_data_size / 3;
+    if (cc_count > 31) {
+        av_log(ctx->log_ctx, AV_LOG_ERROR, "A53 CC can only fit 31 packets "
+               "in a single user data block (got %d).\n", cc_count);
+        return AVERROR(EINVAL);
+    }
+
+    *data = (A53UserData) {
+        .user_identifier = A53_USER_IDENTIFIER_ATSC,
+
+        .atsc = {
+            .user_data_type_code = A53_USER_DATA_TYPE_CODE_CC_DATA,
+
+            .cc_data = {
+                .process_em_data_flag = 0,
+                .process_cc_data_flag = 1,
+                .additional_data_flag = 0,
+
+                .em_data = 0,
+
+                .cc_count = cc_count,
+            },
+        },
+    };
+    cc = &data->atsc.cc_data;
+
+    err = init_get_bits(&gbc, side_data, 8 * side_data_size);
+    if (err < 0)
+        return err;
+
+    for (i = 0; i < cc->cc_count; i++) {
+        err = cbs_misc_read_cea708_cc_data_packet(ctx, &gbc,
+                                                  &cc->cc_data_pkts[i]);
+        if (err < 0)
+            return err;
+    }
+
+    return 0;
+}
+
+int ff_cbs_write_a53_cc_side_data(CodedBitstreamContext *ctx,
+                                  uint8_t **side_data,
+                                  size_t *side_data_size,
+                                  A53UserData *data)
+{
+    PutBitContext pbc;
+    CEA708CCData *cc;
+    int err, i;
+
+    if (data->user_identifier != A53_USER_IDENTIFIER_ATSC ||
+        data->atsc.user_data_type_code != A53_USER_DATA_TYPE_CODE_CC_DATA)
+        return AVERROR(EINVAL);
+
+    cc = &data->atsc.cc_data;
+
+    err = av_reallocp(side_data, *side_data_size + 3 * cc->cc_count);
+    if (err < 0)
+        return err;
+
+    init_put_bits(&pbc, *side_data + *side_data_size, 3 * cc->cc_count);
+
+    for (i = 0; i < cc->cc_count; i++) {
+        err = cbs_misc_write_cea708_cc_data_packet(ctx, &pbc,
+                                                   &cc->cc_data_pkts[i]);
+        if (err < 0) {
+            av_freep(side_data);
+            return err;
+        }
+    }
+
+    flush_put_bits(&pbc);
+    *side_data_size += 3 * cc->cc_count;
+
+    return 0;
+}