xref: /frameworks/av/media/libstagefright/timedtext/TextDescriptions.cpp

/*
 * Copyright (C) 2011 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

#include "TextDescriptions.h"
#include <media/stagefright/Utils.h>
#include <media/stagefright/MediaErrors.h>

namespace android {

TextDescriptions::TextDescriptions() {
}

status_t TextDescriptions::getParcelOfDescriptions(
        const uint8_t *data, ssize_t size,
        uint32_t flags, int timeMs, Parcel *parcel) {
    parcel->freeData();

    if (flags & IN_BAND_TEXT_3GPP) {
        if (flags & GLOBAL_DESCRIPTIONS) {
            return extract3GPPGlobalDescriptions(data, size, parcel, 0);
        } else if (flags & LOCAL_DESCRIPTIONS) {
            return extract3GPPLocalDescriptions(data, size, timeMs, parcel, 0);
        }
    } else if (flags & OUT_OF_BAND_TEXT_SRT) {
        if (flags & LOCAL_DESCRIPTIONS) {
            return extractSRTLocalDescriptions(data, size, timeMs, parcel);
        }
    }

    return ERROR_UNSUPPORTED;
}

// Parse the SRT text sample, and store the timing and text sample in a Parcel.
// The Parcel will be sent to MediaPlayer.java through event, and will be
// parsed in TimedText.java.
status_t TextDescriptions::extractSRTLocalDescriptions(
        const uint8_t *data, ssize_t size, int timeMs, Parcel *parcel) {
    parcel->writeInt32(KEY_LOCAL_SETTING);
    parcel->writeInt32(KEY_START_TIME);
    parcel->writeInt32(timeMs);

    parcel->writeInt32(KEY_STRUCT_TEXT);
    // write the size of the text sample
    parcel->writeInt32(size);
    // write the text sample as a byte array
    parcel->writeInt32(size);
    parcel->write(data, size);

    return OK;
}

// Extract the local 3GPP display descriptions. 3GPP local descriptions
// are appended to the text sample if any. The descriptions could include
// information such as text styles, highlights, karaoke and so on. They
// are contained in different boxes, such as 'styl' box contains text
// styles, and 'krok' box contains karaoke timing and positions.
status_t TextDescriptions::extract3GPPLocalDescriptions(
        const uint8_t *data, ssize_t size,
        int timeMs, Parcel *parcel, int depth) {
    if (depth == 0) {
        parcel->writeInt32(KEY_LOCAL_SETTING);

        // write start time to display this text sample
        parcel->writeInt32(KEY_START_TIME);
        parcel->writeInt32(timeMs);

        ssize_t textLen = (*data) << 8 | (*(data + 1));

        // write text sample length and text sample itself
        parcel->writeInt32(KEY_STRUCT_TEXT);
        parcel->writeInt32(textLen);
        parcel->writeInt32(textLen);
        parcel->write(data + 2, textLen);

        if (size > textLen) {
            data += (textLen + 2);
            size -= (textLen + 2);
        } else {
            return OK;
        }
    }

    const uint8_t *tmpData = data;
    ssize_t chunkSize = U32_AT(tmpData);
    uint32_t chunkType = U32_AT(tmpData + 4);

    if (chunkSize <= 0) {
        return OK;
    }

    tmpData += 8;

    switch(chunkType) {
        // 'styl' box specifies the style of the text.
        case FOURCC('s', 't', 'y', 'l'):
        {
            uint16_t count = U16_AT(tmpData);

            tmpData += 2;

            for (int i = 0; i < count; i++) {
                parcel->writeInt32(KEY_STRUCT_STYLE_LIST);
                parcel->writeInt32(KEY_START_CHAR);
                parcel->writeInt32(U16_AT(tmpData));

                parcel->writeInt32(KEY_END_CHAR);
                parcel->writeInt32(U16_AT(tmpData + 2));

                parcel->writeInt32(KEY_FONT_ID);
                parcel->writeInt32(U16_AT(tmpData + 4));

                parcel->writeInt32(KEY_STYLE_FLAGS);
                parcel->writeInt32(*(tmpData + 6));

                parcel->writeInt32(KEY_FONT_SIZE);
                parcel->writeInt32(*(tmpData + 7));

                parcel->writeInt32(KEY_TEXT_COLOR_RGBA);
                uint32_t rgba = *(tmpData + 8) << 24 | *(tmpData + 9) << 16
                    | *(tmpData + 10) << 8 | *(tmpData + 11);
                parcel->writeInt32(rgba);

                tmpData += 12;
            }

            break;
        }
        // 'krok' box. The number of highlight events is specified, and each
        // event is specified by a starting and ending char offset and an end
        // time for the event.
        case FOURCC('k', 'r', 'o', 'k'):
        {

            parcel->writeInt32(KEY_STRUCT_KARAOKE_LIST);

            int startTime = U32_AT(tmpData);
            uint16_t count = U16_AT(tmpData + 4);
            parcel->writeInt32(count);

            tmpData += 6;
            int lastEndTime = 0;

            for (int i = 0; i < count; i++) {
                parcel->writeInt32(startTime + lastEndTime);

                lastEndTime = U32_AT(tmpData);
                parcel->writeInt32(lastEndTime);

                parcel->writeInt32(U16_AT(tmpData + 4));
                parcel->writeInt32(U16_AT(tmpData + 6));

                tmpData += 8;
            }

            break;
        }
        // 'hlit' box specifies highlighted text
        case FOURCC('h', 'l', 'i', 't'):
        {
            parcel->writeInt32(KEY_STRUCT_HIGHLIGHT_LIST);

            // the start char offset to highlight
            parcel->writeInt32(U16_AT(tmpData));
            // the last char offset to highlight
            parcel->writeInt32(U16_AT(tmpData + 2));

            break;
        }
        // 'hclr' box specifies the RGBA color: 8 bits each of
        // red, green, blue, and an alpha(transparency) value
        case FOURCC('h', 'c', 'l', 'r'):
        {
            parcel->writeInt32(KEY_HIGHLIGHT_COLOR_RGBA);

            uint32_t rgba = *(tmpData) << 24 | *(tmpData + 1) << 16
                | *(tmpData + 2) << 8 | *(tmpData + 3);
            parcel->writeInt32(rgba);

            break;
        }
        // 'dlay' box specifies a delay after a scroll in and/or
        // before scroll out.
        case FOURCC('d', 'l', 'a', 'y'):
        {
            parcel->writeInt32(KEY_SCROLL_DELAY);

            uint32_t delay = *(tmpData) << 24 | *(tmpData + 1) << 16
                | *(tmpData + 2) << 8 | *(tmpData + 3);
            parcel->writeInt32(delay);

            break;
        }
        // 'href' box for hyper text link
        case FOURCC('h', 'r', 'e', 'f'):
        {
            parcel->writeInt32(KEY_STRUCT_HYPER_TEXT_LIST);

            // the start offset of the text to be linked
            parcel->writeInt32(U16_AT(tmpData));
            // the end offset of the text
            parcel->writeInt32(U16_AT(tmpData + 2));

            // the number of bytes in the following URL
            int len = *(tmpData + 4);
            parcel->writeInt32(len);

            // the linked-to URL
            parcel->writeInt32(len);
            parcel->write(tmpData + 5, len);

            tmpData += (5 + len);

            // the number of bytes in the following "alt" string
            len = *tmpData;
            parcel->writeInt32(len);

            // an "alt" string for user display
            parcel->writeInt32(len);
            parcel->write(tmpData + 1, len);

            break;
        }
        // 'tbox' box to indicate the position of the text with values
        // of top, left, bottom and right
        case FOURCC('t', 'b', 'o', 'x'):
        {
            parcel->writeInt32(KEY_STRUCT_TEXT_POS);
            parcel->writeInt32(U16_AT(tmpData));
            parcel->writeInt32(U16_AT(tmpData + 2));
            parcel->writeInt32(U16_AT(tmpData + 4));
            parcel->writeInt32(U16_AT(tmpData + 6));

            break;
        }
        // 'blnk' to specify the char range to be blinked
        case FOURCC('b', 'l', 'n', 'k'):
        {
            parcel->writeInt32(KEY_STRUCT_BLINKING_TEXT_LIST);

            // start char offset
            parcel->writeInt32(U16_AT(tmpData));
            // end char offset
            parcel->writeInt32(U16_AT(tmpData + 2));

            break;
        }
        // 'twrp' box specifies text wrap behavior. If the value if 0x00,
        // then no wrap. If it's 0x01, then automatic 'soft' wrap is enabled.
        // 0x02-0xff are reserved.
        case FOURCC('t', 'w', 'r', 'p'):
        {
            parcel->writeInt32(KEY_WRAP_TEXT);
            parcel->writeInt32(*tmpData);

            break;
        }
        default:
        {
            break;
        }
    }

    if (size > chunkSize) {
        data += chunkSize;
        size -= chunkSize;
        // continue to parse next box
        return extract3GPPLocalDescriptions(data, size, 0, parcel, 1);
    }

    return OK;
}

// To extract box 'tx3g' defined in 3GPP TS 26.245, and store it in a Parcel
status_t TextDescriptions::extract3GPPGlobalDescriptions(
        const uint8_t *data, ssize_t size, Parcel *parcel, int depth) {

    ssize_t chunkSize = U32_AT(data);
    uint32_t chunkType = U32_AT(data + 4);
    const uint8_t *tmpData = data;
    tmpData += 8;

    if (size < chunkSize) {
        return OK;
    }

    if (depth == 0) {
        parcel->writeInt32(KEY_GLOBAL_SETTING);
    }
    switch(chunkType) {
        case FOURCC('t', 'x', '3', 'g'):
        {
            tmpData += 8; // skip the first 8 bytes
            parcel->writeInt32(KEY_DISPLAY_FLAGS);
            parcel->writeInt32(U32_AT(tmpData));

            parcel->writeInt32(KEY_STRUCT_JUSTIFICATION);
            parcel->writeInt32(tmpData[4]);
            parcel->writeInt32(tmpData[5]);

            parcel->writeInt32(KEY_BACKGROUND_COLOR_RGBA);
            uint32_t rgba = *(tmpData + 6) << 24 | *(tmpData + 7) << 16
                | *(tmpData + 8) << 8 | *(tmpData + 9);
            parcel->writeInt32(rgba);

            tmpData += 10;
            parcel->writeInt32(KEY_STRUCT_TEXT_POS);
            parcel->writeInt32(U16_AT(tmpData));
            parcel->writeInt32(U16_AT(tmpData + 2));
            parcel->writeInt32(U16_AT(tmpData + 4));
            parcel->writeInt32(U16_AT(tmpData + 6));

            tmpData += 8;
            parcel->writeInt32(KEY_STRUCT_STYLE_LIST);
            parcel->writeInt32(KEY_START_CHAR);
            parcel->writeInt32(U16_AT(tmpData));

            parcel->writeInt32(KEY_END_CHAR);
            parcel->writeInt32(U16_AT(tmpData + 2));

            parcel->writeInt32(KEY_FONT_ID);
            parcel->writeInt32(U16_AT(tmpData + 4));

            parcel->writeInt32(KEY_STYLE_FLAGS);
            parcel->writeInt32(*(tmpData + 6));

            parcel->writeInt32(KEY_FONT_SIZE);
            parcel->writeInt32(*(tmpData + 7));

            parcel->writeInt32(KEY_TEXT_COLOR_RGBA);
            rgba = *(tmpData + 8) << 24 | *(tmpData + 9) << 16
                | *(tmpData + 10) << 8 | *(tmpData + 11);
            parcel->writeInt32(rgba);

            tmpData += 12;
            parcel->writeInt32(KEY_STRUCT_FONT_LIST);
            uint16_t count = U16_AT(tmpData);
            parcel->writeInt32(count);

            tmpData += 2;
            for (int i = 0; i < count; i++) {
                // font ID
                parcel->writeInt32(U16_AT(tmpData));

                // font name length
                parcel->writeInt32(*(tmpData + 2));

                int len = *(tmpData + 2);

                parcel->write(tmpData + 3, len);
                tmpData += 3 + len;
            }

            break;
        }
        default:
        {
            break;
        }
    }

    data += chunkSize;
    size -= chunkSize;

    if (size > 0) {
        // continue to extract next 'tx3g'
        return extract3GPPGlobalDescriptions(data, size, parcel, 1);
    }

    return OK;
}

}  // namespace android