[FFmpeg-devel] [PATCH v2 14/16] avcodec/dca: add EXSS parser

foo86 foobaz86 at gmail.com
Thu Jan 21 19:49:33 CET 2016


---
 libavcodec/dca_exss.c | 514 ++++++++++++++++++++++++++++++++++++++++++++++++++
 libavcodec/dca_exss.h |  92 +++++++++
 2 files changed, 606 insertions(+)
 create mode 100644 libavcodec/dca_exss.c
 create mode 100644 libavcodec/dca_exss.h

diff --git a/libavcodec/dca_exss.c b/libavcodec/dca_exss.c
new file mode 100644
index 0000000..4579f23
--- /dev/null
+++ b/libavcodec/dca_exss.c
@@ -0,0 +1,514 @@
+/*
+ * Copyright (C) 2016 foo86
+ *
+ * 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 "dcadec.h"
+#include "dcadata.h"
+
+static int count_chs_for_mask(int mask)
+{
+    return av_popcount(mask) + av_popcount(mask & 0xae66);
+}
+
+static void parse_xll_parameters(DCAExssParser *s, DCAExssAsset *asset)
+{
+    // Size of XLL data in extension substream
+    asset->xll_size = get_bits(&s->gb, s->exss_size_nbits) + 1;
+
+    // XLL sync word present flag
+    if (asset->xll_sync_present = get_bits1(&s->gb)) {
+        int xll_delay_nbits;
+
+        // Peak bit rate smoothing buffer size
+        skip_bits(&s->gb, 4);
+
+        // Number of bits for XLL decoding delay
+        xll_delay_nbits = get_bits(&s->gb, 5) + 1;
+
+        // Initial XLL decoding delay in frames
+        asset->xll_delay_nframes = get_bits_long(&s->gb, xll_delay_nbits);
+
+        // Number of bytes offset to XLL sync
+        asset->xll_sync_offset = get_bits(&s->gb, s->exss_size_nbits);
+    } else {
+        asset->xll_delay_nframes = 0;
+        asset->xll_sync_offset = 0;
+    }
+}
+
+static void parse_lbr_parameters(DCAExssParser *s, DCAExssAsset *asset)
+{
+    // Size of LBR component in extension substream
+    asset->lbr_size = get_bits(&s->gb, 14) + 1;
+
+    // LBR sync word present flag
+    if (get_bits1(&s->gb))
+        // LBR sync distance
+        skip_bits(&s->gb, 2);
+}
+
+static int parse_descriptor(DCAExssParser *s, DCAExssAsset *asset)
+{
+    int i, j, drc_present, descr_size, descr_pos = get_bits_count(&s->gb);
+
+    // Size of audio asset descriptor in bytes
+    descr_size = get_bits(&s->gb, 9) + 1;
+
+    // Audio asset identifier
+    asset->asset_index = get_bits(&s->gb, 3);
+
+    //
+    // Per stream static metadata
+    //
+
+    if (s->static_fields_present) {
+        // Asset type descriptor presence
+        if (get_bits1(&s->gb))
+            // Asset type descriptor
+            skip_bits(&s->gb, 4);
+
+        // Language descriptor presence
+        if (get_bits1(&s->gb))
+            // Language descriptor
+            skip_bits(&s->gb, 24);
+
+        // Additional textual information presence
+        if (get_bits1(&s->gb)) {
+            // Byte size of additional text info
+            int text_size = get_bits(&s->gb, 10) + 1;
+
+            // Sanity check available size
+            if (get_bits_left(&s->gb) < text_size * 8)
+                return AVERROR_INVALIDDATA;
+
+            // Additional textual information string
+            skip_bits_long(&s->gb, text_size * 8);
+        }
+
+        // PCM bit resolution
+        asset->pcm_bit_res = get_bits(&s->gb, 5) + 1;
+
+        // Maximum sample rate
+        asset->max_sample_rate = ff_dca_sampling_freqs[get_bits(&s->gb, 4)];
+
+        // Total number of channels
+        asset->nchannels_total = get_bits(&s->gb, 8) + 1;
+
+        // One to one map channel to speakers
+        if (asset->one_to_one_map_ch_to_spkr = get_bits1(&s->gb)) {
+            int spkr_mask_nbits = 0;
+            int spkr_remap_nsets;
+            int nspeakers[8];
+
+            // Embedded stereo flag
+            if (asset->nchannels_total > 2)
+                asset->embedded_stereo = get_bits1(&s->gb);
+
+            // Embedded 6 channels flag
+            if (asset->nchannels_total > 6)
+                asset->embedded_6ch = get_bits1(&s->gb);
+
+            // Speaker mask enabled flag
+            if (asset->spkr_mask_enabled = get_bits1(&s->gb)) {
+                // Number of bits for speaker activity mask
+                spkr_mask_nbits = (get_bits(&s->gb, 2) + 1) << 2;
+
+                // Loudspeaker activity mask
+                asset->spkr_mask = get_bits(&s->gb, spkr_mask_nbits);
+            }
+
+            // Number of speaker remapping sets
+            if ((spkr_remap_nsets = get_bits(&s->gb, 3)) && !spkr_mask_nbits) {
+                av_log(s->avctx, AV_LOG_ERROR, "Speaker mask disabled yet there are remapping sets\n");
+                return AVERROR_INVALIDDATA;
+            }
+
+            // Standard loudspeaker layout mask
+            for (i = 0; i < spkr_remap_nsets; i++)
+                nspeakers[i] = count_chs_for_mask(get_bits(&s->gb, spkr_mask_nbits));
+
+            for (i = 0; i < spkr_remap_nsets; i++) {
+                // Number of channels to be decoded for speaker remapping
+                int nch_for_remaps = get_bits(&s->gb, 5) + 1;
+
+                for (j = 0; j < nspeakers[i]; j++) {
+                    // Decoded channels to output speaker mapping mask
+                    int remap_ch_mask = get_bits_long(&s->gb, nch_for_remaps);
+
+                    // Loudspeaker remapping codes
+                    skip_bits_long(&s->gb, av_popcount(remap_ch_mask) * 5);
+                }
+            }
+        } else {
+            asset->embedded_stereo = 0;
+            asset->embedded_6ch = 0;
+            asset->spkr_mask_enabled = 0;
+            asset->spkr_mask = 0;
+
+            // Representation type
+            asset->representation_type = get_bits(&s->gb, 3);
+        }
+    }
+
+    //
+    // DRC, DNC and mixing metadata
+    //
+
+    // Dynamic range coefficient presence flag
+    drc_present = get_bits1(&s->gb);
+
+    // Code for dynamic range coefficient
+    if (drc_present)
+        skip_bits(&s->gb, 8);
+
+    // Dialog normalization presence flag
+    if (get_bits1(&s->gb))
+        // Dialog normalization code
+        skip_bits(&s->gb, 5);
+
+    // DRC for stereo downmix
+    if (drc_present && asset->embedded_stereo)
+        skip_bits(&s->gb, 8);
+
+    // Mixing metadata presence flag
+    if (s->mix_metadata_enabled && get_bits1(&s->gb)) {
+        int nchannels_dmix;
+
+        // External mixing flag
+        skip_bits1(&s->gb);
+
+        // Post mixing / replacement gain adjustment
+        skip_bits(&s->gb, 6);
+
+        // DRC prior to mixing
+        if (get_bits(&s->gb, 2) == 3)
+            // Custom code for mixing DRC
+            skip_bits(&s->gb, 8);
+        else
+            // Limit for mixing DRC
+            skip_bits(&s->gb, 3);
+
+        // Scaling type for channels of main audio
+        // Scaling parameters of main audio
+        if (get_bits1(&s->gb))
+            for (i = 0; i < s->nmixoutconfigs; i++)
+                skip_bits_long(&s->gb, 6 * s->nmixoutchs[i]);
+        else
+            skip_bits_long(&s->gb, 6 * s->nmixoutconfigs);
+
+        nchannels_dmix = asset->nchannels_total;
+        if (asset->embedded_6ch)
+            nchannels_dmix += 6;
+        if (asset->embedded_stereo)
+            nchannels_dmix += 2;
+
+        for (i = 0; i < s->nmixoutconfigs; i++) {
+            if (!s->nmixoutchs[i]) {
+                av_log(s->avctx, AV_LOG_ERROR, "Invalid speaker layout mask for mixing configuration\n");
+                return AVERROR_INVALIDDATA;
+            }
+            for (j = 0; j < nchannels_dmix; j++) {
+                // Mix output mask
+                int mix_map_mask = get_bits(&s->gb, s->nmixoutchs[i]);
+
+                // Mixing coefficients
+                skip_bits_long(&s->gb, av_popcount(mix_map_mask) * 6);
+            }
+        }
+    }
+
+    //
+    // Decoder navigation data
+    //
+
+    // Coding mode for the asset
+    asset->coding_mode = get_bits(&s->gb, 2);
+
+    // Coding components used in asset
+    switch (asset->coding_mode) {
+    case 0: // Coding mode that may contain multiple coding components
+        asset->extension_mask = get_bits(&s->gb, 12);
+
+        if (asset->extension_mask & DCA_EXSS_CORE) {
+            // Size of core component in extension substream
+            asset->core_size = get_bits(&s->gb, 14) + 1;
+            // Core sync word present flag
+            if (get_bits1(&s->gb))
+                // Core sync distance
+                skip_bits(&s->gb, 2);
+        }
+
+        if (asset->extension_mask & DCA_EXSS_XBR)
+            // Size of XBR extension in extension substream
+            asset->xbr_size = get_bits(&s->gb, 14) + 1;
+
+        if (asset->extension_mask & DCA_EXSS_XXCH)
+            // Size of XXCH extension in extension substream
+            asset->xxch_size = get_bits(&s->gb, 14) + 1;
+
+        if (asset->extension_mask & DCA_EXSS_X96)
+            // Size of X96 extension in extension substream
+            asset->x96_size = get_bits(&s->gb, 12) + 1;
+
+        if (asset->extension_mask & DCA_EXSS_LBR)
+            parse_lbr_parameters(s, asset);
+
+        if (asset->extension_mask & DCA_EXSS_XLL)
+            parse_xll_parameters(s, asset);
+
+        if (asset->extension_mask & DCA_EXSS_RSV1)
+            skip_bits(&s->gb, 16);
+
+        if (asset->extension_mask & DCA_EXSS_RSV2)
+            skip_bits(&s->gb, 16);
+        break;
+
+    case 1: // Loss-less coding mode without CBR component
+        asset->extension_mask = DCA_EXSS_XLL;
+        parse_xll_parameters(s, asset);
+        break;
+
+    case 2: // Low bit rate mode
+        asset->extension_mask = DCA_EXSS_LBR;
+        parse_lbr_parameters(s, asset);
+        break;
+
+    case 3: // Auxiliary coding mode
+        asset->extension_mask = 0;
+
+        // Size of auxiliary coded data
+        skip_bits(&s->gb, 14);
+
+        // Auxiliary codec identification
+        skip_bits(&s->gb, 8);
+
+        // Aux sync word present flag
+        if (get_bits1(&s->gb))
+            // Aux sync distance
+            skip_bits(&s->gb, 3);
+        break;
+    }
+
+    if (asset->extension_mask & DCA_EXSS_XLL)
+        // DTS-HD stream ID
+        asset->hd_stream_id = get_bits(&s->gb, 3);
+
+    // One to one mixing flag
+    // Per channel main audio scaling flag
+    // Main audio scaling codes
+    // Decode asset in secondary decoder flag
+    // Revision 2 DRC metadata
+    // Reserved
+    // Zero pad
+    if (ff_dca_seek_bits(&s->gb, descr_pos + descr_size * 8)) {
+        av_log(s->avctx, AV_LOG_ERROR, "Read past end of EXSS asset descriptor\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    return 0;
+}
+
+static int set_exss_offsets(DCAExssAsset *asset)
+{
+    int offs = asset->asset_offset;
+    int size = asset->asset_size;
+
+    if (asset->extension_mask & DCA_EXSS_CORE) {
+        asset->core_offset = offs;
+        if (asset->core_size > size)
+            return AVERROR_INVALIDDATA;
+        offs += asset->core_size;
+        size -= asset->core_size;
+    }
+
+    if (asset->extension_mask & DCA_EXSS_XBR) {
+        asset->xbr_offset = offs;
+        if (asset->xbr_size > size)
+            return AVERROR_INVALIDDATA;
+        offs += asset->xbr_size;
+        size -= asset->xbr_size;
+    }
+
+    if (asset->extension_mask & DCA_EXSS_XXCH) {
+        asset->xxch_offset = offs;
+        if (asset->xxch_size > size)
+            return AVERROR_INVALIDDATA;
+        offs += asset->xxch_size;
+        size -= asset->xxch_size;
+    }
+
+    if (asset->extension_mask & DCA_EXSS_X96) {
+        asset->x96_offset = offs;
+        if (asset->x96_size > size)
+            return AVERROR_INVALIDDATA;
+        offs += asset->x96_size;
+        size -= asset->x96_size;
+    }
+
+    if (asset->extension_mask & DCA_EXSS_LBR) {
+        asset->lbr_offset = offs;
+        if (asset->lbr_size > size)
+            return AVERROR_INVALIDDATA;
+        offs += asset->lbr_size;
+        size -= asset->lbr_size;
+    }
+
+    if (asset->extension_mask & DCA_EXSS_XLL) {
+        asset->xll_offset = offs;
+        if (asset->xll_size > size)
+            return AVERROR_INVALIDDATA;
+        offs += asset->xll_size;
+        size -= asset->xll_size;
+    }
+
+    return 0;
+}
+
+int ff_dca_exss_parse(DCAExssParser *s, uint8_t *data, int size)
+{
+    int i, ret, offset, wide_hdr, header_size;
+
+    if ((ret = init_get_bits8(&s->gb, data, size)) < 0)
+        return ret;
+
+    // Extension substream sync word
+    skip_bits_long(&s->gb, 32);
+
+    // User defined bits
+    skip_bits(&s->gb, 8);
+
+    // Extension substream index
+    s->exss_index = get_bits(&s->gb, 2);
+
+    // Flag indicating short or long header size
+    wide_hdr = get_bits1(&s->gb);
+
+    // Extension substream header length
+    header_size = get_bits(&s->gb, 8 + 4 * wide_hdr) + 1;
+
+    // Check CRC
+    if ((s->avctx->err_recognition & (AV_EF_CRCCHECK | AV_EF_CAREFUL))
+        && ff_dca_check_crc(&s->gb, 32 + 8, header_size * 8)) {
+        av_log(s->avctx, AV_LOG_ERROR, "Invalid EXSS header checksum\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    s->exss_size_nbits = 16 + 4 * wide_hdr;
+
+    // Number of bytes of extension substream
+    s->exss_size = get_bits(&s->gb, s->exss_size_nbits) + 1;
+    if (s->exss_size > size) {
+        av_log(s->avctx, AV_LOG_ERROR, "Packet too short for EXSS frame\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    // Per stream static fields presence flag
+    if (s->static_fields_present = get_bits1(&s->gb)) {
+        int active_exss_mask[8];
+
+        // Reference clock code
+        skip_bits(&s->gb, 2);
+
+        // Extension substream frame duration
+        skip_bits(&s->gb, 3);
+
+        // Timecode presence flag
+        if (get_bits1(&s->gb))
+            // Timecode data
+            skip_bits_long(&s->gb, 36);
+
+        // Number of defined audio presentations
+        s->npresents = get_bits(&s->gb, 3) + 1;
+        if (s->npresents > 1) {
+            avpriv_request_sample(s->avctx, "%d audio presentations", s->npresents);
+            return AVERROR_PATCHWELCOME;
+        }
+
+        // Number of audio assets in extension substream
+        s->nassets = get_bits(&s->gb, 3) + 1;
+        if (s->nassets > 1) {
+            avpriv_request_sample(s->avctx, "%d audio assets", s->nassets);
+            return AVERROR_PATCHWELCOME;
+        }
+
+        // Active extension substream mask for audio presentation
+        for (i = 0; i < s->npresents; i++)
+            active_exss_mask[i] = get_bits(&s->gb, s->exss_index + 1);
+
+        // Active audio asset mask
+        for (i = 0; i < s->npresents; i++)
+            skip_bits_long(&s->gb, av_popcount(active_exss_mask[i]) * 8);
+
+        // Mixing metadata enable flag
+        if (s->mix_metadata_enabled = get_bits1(&s->gb)) {
+            int spkr_mask_nbits;
+
+            // Mixing metadata adjustment level
+            skip_bits(&s->gb, 2);
+
+            // Number of bits for mixer output speaker activity mask
+            spkr_mask_nbits = (get_bits(&s->gb, 2) + 1) << 2;
+
+            // Number of mixing configurations
+            s->nmixoutconfigs = get_bits(&s->gb, 2) + 1;
+
+            // Speaker layout mask for mixer output channels
+            for (i = 0; i < s->nmixoutconfigs; i++)
+                s->nmixoutchs[i] = count_chs_for_mask(get_bits(&s->gb, spkr_mask_nbits));
+        }
+    } else {
+        s->npresents = 1;
+        s->nassets = 1;
+    }
+
+    // Size of encoded asset data in bytes
+    offset = header_size;
+    for (i = 0; i < s->nassets; i++) {
+        s->assets[i].asset_offset = offset;
+        s->assets[i].asset_size = get_bits(&s->gb, s->exss_size_nbits) + 1;
+        offset += s->assets[i].asset_size;
+        if (offset > s->exss_size) {
+            av_log(s->avctx, AV_LOG_ERROR, "EXSS asset out of bounds\n");
+            return AVERROR_INVALIDDATA;
+        }
+    }
+
+    // Audio asset descriptor
+    for (i = 0; i < s->nassets; i++) {
+        if ((ret = parse_descriptor(s, &s->assets[i])) < 0)
+            return ret;
+        if ((ret = set_exss_offsets(&s->assets[i])) < 0) {
+            av_log(s->avctx, AV_LOG_ERROR, "Invalid extension size in EXSS asset descriptor\n");
+            return ret;
+        }
+    }
+
+    // Backward compatible core present
+    // Backward compatible core substream index
+    // Backward compatible core asset index
+    // Reserved
+    // Byte align
+    // CRC16 of extension substream header
+    if (ff_dca_seek_bits(&s->gb, header_size * 8)) {
+        av_log(s->avctx, AV_LOG_ERROR, "Read past end of EXSS header\n");
+        return AVERROR_INVALIDDATA;
+    }
+
+    return 0;
+}
diff --git a/libavcodec/dca_exss.h b/libavcodec/dca_exss.h
new file mode 100644
index 0000000..323063a
--- /dev/null
+++ b/libavcodec/dca_exss.h
@@ -0,0 +1,92 @@
+/*
+ * Copyright (C) 2016 foo86
+ *
+ * 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
+ */
+
+#ifndef AVCODEC_DCA_EXSS_H
+#define AVCODEC_DCA_EXSS_H
+
+#include "libavutil/common.h"
+
+#include "avcodec.h"
+#include "get_bits.h"
+
+typedef struct DCAExssAsset {
+    int     asset_offset;   ///< Offset to asset data from start of substream
+    int     asset_size;     ///< Size of encoded asset data
+    int     asset_index;    ///< Audio asset identifier
+
+    int     pcm_bit_res;                ///< PCM bit resolution
+    int     max_sample_rate;            ///< Maximum sample rate
+    int     nchannels_total;            ///< Total number of channels
+    int     one_to_one_map_ch_to_spkr;  ///< One to one channel to speaker mapping flag
+    int     embedded_stereo;            ///< Embedded stereo flag
+    int     embedded_6ch;               ///< Embedded 6 channels flag
+    int     spkr_mask_enabled;          ///< Speaker mask enabled flag
+    int     spkr_mask;                  ///< Loudspeaker activity mask
+    int     representation_type;        ///< Representation type
+
+    int     coding_mode;        ///< Coding mode for the asset
+    int     extension_mask;     ///< Coding components used in asset
+
+    int     core_offset;    ///< Offset to core component from start of substream
+    int     core_size;      ///< Size of core component in extension substream
+
+    int     xbr_offset;     ///< Offset to XBR extension from start of substream
+    int     xbr_size;       ///< Size of XBR extension in extension substream
+
+    int     xxch_offset;    ///< Offset to XXCH extension from start of substream
+    int     xxch_size;      ///< Size of XXCH extension in extension substream
+
+    int     x96_offset;     ///< Offset to X96 extension from start of substream
+    int     x96_size;       ///< Size of X96 extension in extension substream
+
+    int     lbr_offset;     ///< Offset to LBR component from start of substream
+    int     lbr_size;       ///< Size of LBR component in extension substream
+
+    int     xll_offset;         ///< Offset to XLL data from start of substream
+    int     xll_size;           ///< Size of XLL data in extension substream
+    int     xll_sync_present;   ///< XLL sync word present flag
+    int     xll_delay_nframes;  ///< Initial XLL decoding delay in frames
+    int     xll_sync_offset;    ///< Number of bytes offset to XLL sync
+
+    int     hd_stream_id;   ///< DTS-HD stream ID
+} DCAExssAsset;
+
+typedef struct DCAExssParser {
+    AVCodecContext  *avctx;
+    GetBitContext   gb;
+
+    int     exss_index;         ///< Extension substream index
+    int     exss_size_nbits;    ///< Number of bits for extension substream size
+    int     exss_size;          ///< Number of bytes of extension substream
+
+    int     static_fields_present;  ///< Per stream static fields presence flag
+    int     npresents;  ///< Number of defined audio presentations
+    int     nassets;    ///< Number of audio assets in extension substream
+
+    int     mix_metadata_enabled;   ///< Mixing metadata enable flag
+    int     nmixoutconfigs;         ///< Number of mixing configurations
+    int     nmixoutchs[4];          ///< Speaker layout mask for mixer output channels
+
+    DCAExssAsset   assets[1];    ///< Audio asset descriptors
+} DCAExssParser;
+
+int ff_dca_exss_parse(DCAExssParser *s, uint8_t *data, int size);
+
+#endif
-- 
2.1.4



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