early-access version 1432

externals/ffmpeg/libavcodec/truehd_core_bsf.c

@@ -0,0 +1,182 @@
+/*
+ * Copyright (c) 2018 Paul B Mahol
+ *
+ * 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 "bsf.h"
+#include "bsf_internal.h"
+#include "get_bits.h"
+#include "mlp_parse.h"
+#include "mlp.h"
+
+typedef struct AccessUnit {
+    uint8_t bits[4];
+    uint16_t offset;
+    uint16_t optional;
+} AccessUnit;
+
+typedef struct TrueHDCoreContext {
+    MLPHeaderInfo hdr;
+} TrueHDCoreContext;
+
+static int truehd_core_filter(AVBSFContext *ctx, AVPacket *pkt)
+{
+    TrueHDCoreContext *s = ctx->priv_data;
+    GetBitContext gbc;
+    AccessUnit units[MAX_SUBSTREAMS];
+    int ret, i, last_offset = 0;
+    int in_size, out_size;
+    int have_header = 0;
+    int substream_bytes = 0;
+    int end;
+
+    ret = ff_bsf_get_packet_ref(ctx, pkt);
+    if (ret < 0)
+        return ret;
+
+    if (pkt->size < 4) {
+        ret = AVERROR_INVALIDDATA;
+        goto fail;
+    }
+
+    in_size = (AV_RB16(pkt->data) & 0xFFF) * 2;
+    if (in_size < 4 || in_size > pkt->size) {
+        ret = AVERROR_INVALIDDATA;
+        goto fail;
+    }
+
+    ret = init_get_bits8(&gbc, pkt->data + 4, pkt->size - 4);
+    if (ret < 0)
+        goto fail;
+
+    if (show_bits_long(&gbc, 32) == 0xf8726fba) {
+        if ((ret = ff_mlp_read_major_sync(ctx, &s->hdr, &gbc)) < 0)
+            goto fail;
+        have_header = 1;
+    }
+
+    if (s->hdr.num_substreams > MAX_SUBSTREAMS) {
+        ret = AVERROR_INVALIDDATA;
+        goto fail;
+    }
+
+    for (i = 0; i < s->hdr.num_substreams; i++) {
+        for (int j = 0; j < 4; j++)
+            units[i].bits[j] = get_bits1(&gbc);
+
+        units[i].offset = get_bits(&gbc, 12);
+        if (i < 3) {
+            last_offset = units[i].offset * 2;
+            substream_bytes += 2;
+        }
+
+        if (units[i].bits[0]) {
+            units[i].optional = get_bits(&gbc, 16);
+            if (i < 3)
+                substream_bytes += 2;
+        }
+    }
+    end = get_bits_count(&gbc) >> 3;
+
+    out_size = end + 4 + last_offset;
+    if (out_size < in_size) {
+        int bpos = 0, reduce = end - have_header * 28 - substream_bytes;
+        uint16_t parity_nibble, dts = AV_RB16(pkt->data + 2);
+        uint16_t auheader;
+        uint8_t header[28];
+
+        av_assert1(reduce >= 0 && reduce % 2 == 0);
+
+        if (have_header) {
+            memcpy(header, pkt->data + 4, 28);
+            header[16]  = (header[16] & 0x0c) | (FFMIN(s->hdr.num_substreams, 3) << 4);
+            header[17] &= 0x7f;
+            header[25] &= 0xfe;
+            AV_WL16(header + 26, ff_mlp_checksum16(header, 26));
+        }
+
+        pkt->data += reduce;
+        out_size  -= reduce;
+        pkt->size  = out_size;
+
+        ret = av_packet_make_writable(pkt);
+        if (ret < 0)
+            goto fail;
+
+        AV_WB16(pkt->data + 2, dts);
+        parity_nibble = dts;
+        parity_nibble ^= out_size / 2;
+
+        for (i = 0; i < FFMIN(s->hdr.num_substreams, 3); i++) {
+            uint16_t substr_hdr = 0;
+
+            substr_hdr |= (units[i].bits[0] << 15);
+            substr_hdr |= (units[i].bits[1] << 14);
+            substr_hdr |= (units[i].bits[2] << 13);
+            substr_hdr |= (units[i].bits[3] << 12);
+            substr_hdr |=  units[i].offset;
+
+            AV_WB16(pkt->data + have_header * 28 + 4 + bpos, substr_hdr);
+
+            parity_nibble ^= substr_hdr;
+            bpos          += 2;
+
+            if (units[i].bits[0]) {
+                AV_WB16(pkt->data + have_header * 28 + 4 + bpos, units[i].optional);
+
+                parity_nibble ^= units[i].optional;
+                bpos          += 2;
+            }
+        }
+
+        parity_nibble ^= parity_nibble >> 8;
+        parity_nibble ^= parity_nibble >> 4;
+        parity_nibble &= 0xF;
+
+        auheader  = (parity_nibble ^ 0xF) << 12;
+        auheader |= (out_size / 2) & 0x0fff;
+        AV_WB16(pkt->data, auheader);
+
+        if (have_header)
+            memcpy(pkt->data + 4, header, 28);
+    }
+
+fail:
+    if (ret < 0)
+        av_packet_unref(pkt);
+
+    return ret;
+}
+
+static void truehd_core_flush(AVBSFContext *ctx)
+{
+    TrueHDCoreContext *s = ctx->priv_data;
+    memset(&s->hdr, 0, sizeof(s->hdr));
+}
+
+static const enum AVCodecID codec_ids[] = {
+    AV_CODEC_ID_TRUEHD, AV_CODEC_ID_NONE,
+};
+
+const AVBitStreamFilter ff_truehd_core_bsf = {
+    .name           = "truehd_core",
+    .priv_data_size = sizeof(TrueHDCoreContext),
+    .filter         = truehd_core_filter,
+    .flush          = truehd_core_flush,
+    .codec_ids      = codec_ids,
+};