FFmpeg/libavformat/rpl.c

/*
 * ARMovie/RPL demuxer
 * Copyright (c) 2007 Christian Ohm, 2008 Eli Friedman
 *
 * 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/avstring.h"
#include "avformat.h"
#include <stdlib.h>

#define RPL_SIGNATURE "ARMovie\x0A"
#define RPL_SIGNATURE_SIZE 8

/** 256 is arbitrary, but should be big enough for any reasonable file. */
#define RPL_LINE_LENGTH 256

static int rpl_probe(AVProbeData *p)
{
    if (memcmp(p->buf, RPL_SIGNATURE, RPL_SIGNATURE_SIZE))
        return 0;

    return AVPROBE_SCORE_MAX;
}

typedef struct RPLContext {
    // RPL header data
    int32_t frames_per_chunk;

    // Stream position data
    uint32_t chunk_number;
    uint32_t chunk_part;
    uint32_t frame_in_part;
} RPLContext;

static int read_line(ByteIOContext * pb, char* line, int bufsize)
{
    int i;
    for (i = 0; i < bufsize - 1; i++) {
        int b = get_byte(pb);
        if (b == 0)
            break;
        if (b == '\n') {
            line[i] = '\0';
            return 0;
        }
        line[i] = b;
    }
    line[i] = '\0';
    return -1;
}

static int32_t read_int(const char* line, const char** endptr, int* error)
{
    unsigned long result = 0;
    for (; *line>='0' && *line<='9'; line++) {
        if (result > (0x7FFFFFFF - 9) / 10)
            *error = -1;
        result = 10 * result + *line - '0';
    }
    *endptr = line;
    return result;
}

static int32_t read_line_and_int(ByteIOContext * pb, int* error)
{
    char line[RPL_LINE_LENGTH];
    const char *endptr;
    *error |= read_line(pb, line, sizeof(line));
    return read_int(line, &endptr, error);
}

/** Parsing for fps, which can be a fraction. Unfortunately,
  * the spec for the header leaves out a lot of details,
  * so this is mostly guessing.
  */
static AVRational read_fps(const char* line, int* error)
{
    int64_t num, den = 1;
    AVRational result;
    num = read_int(line, &line, error);
    if (*line == '.')
        line++;
    for (; *line>='0' && *line<='9'; line++) {
        // Truncate any numerator too large to fit into an int64_t
        if (num > (INT64_MAX - 9) / 10 || den > INT64_MAX / 10)
            break;
        num  = 10 * num + *line - '0';
        den *= 10;
    }
    if (!num)
        *error = -1;
    av_reduce(&result.num, &result.den, num, den, 0x7FFFFFFF);
    return result;
}

static int rpl_read_header(AVFormatContext *s, AVFormatParameters *ap)
{
    ByteIOContext *pb = s->pb;
    RPLContext *rpl = s->priv_data;
    AVStream *vst = NULL, *ast = NULL;
    int total_audio_size;
    int error = 0;

    uint32_t i;

    int32_t audio_format, chunk_catalog_offset, number_of_chunks;
    AVRational fps;

    char line[RPL_LINE_LENGTH];

    // The header for RPL/ARMovie files is 21 lines of text
    // containing the various header fields.  The fields are always
    // in the same order, and other text besides the first
    // number usually isn't important.
    // (The spec says that there exists some significance
    // for the text in a few cases; samples needed.)
    error |= read_line(pb, line        , sizeof(line        ));  // ARMovie
    error |= read_line(pb, s->title    , sizeof(s->title    ));  // movie name
    error |= read_line(pb, s->copyright, sizeof(s->copyright));  // date/copyright
    error |= read_line(pb, s->author   , sizeof(s->author   ));  // author and other

    // video headers
    vst = av_new_stream(s, 0);
    if (!vst)
        return AVERROR(ENOMEM);
    vst->codec->codec_type      = CODEC_TYPE_VIDEO;
    vst->codec->codec_tag       = read_line_and_int(pb, &error);  // video format
    vst->codec->width           = read_line_and_int(pb, &error);  // video width
    vst->codec->height          = read_line_and_int(pb, &error);  // video height
    vst->codec->bits_per_sample = read_line_and_int(pb, &error);  // video bits per sample
    error |= read_line(pb, line, sizeof(line));                   // video frames per second
    fps = read_fps(line, &error);
    av_set_pts_info(vst, 32, fps.den, fps.num);

    // Figure out the video codec
    switch (vst->codec->codec_tag) {
#if 0
        case 122:
            vst->codec->codec_id = CODEC_ID_ESCAPE122;
            break;
#endif
        case 124:
            vst->codec->codec_id = CODEC_ID_ESCAPE124;
            // The header is wrong here, at least sometimes
            vst->codec->bits_per_sample = 16;
            break;
#if 0
        case 130:
            vst->codec->codec_id = CODEC_ID_ESCAPE130;
            break;
#endif
        default:
            av_log(s, AV_LOG_WARNING,
                   "RPL video format %i not supported yet!\n",
                   vst->codec->codec_tag);
            vst->codec->codec_id = CODEC_ID_NONE;
    }

    // Audio headers

    // ARMovie supports multiple audio tracks; I don't have any
    // samples, though. This code will ignore additional tracks.
    audio_format = read_line_and_int(pb, &error);  // audio format ID
    if (audio_format) {
        ast = av_new_stream(s, 0);
        if (!ast)
            return AVERROR(ENOMEM);
        ast->codec->codec_type      = CODEC_TYPE_AUDIO;
        ast->codec->codec_tag       = audio_format;
        ast->codec->sample_rate     = read_line_and_int(pb, &error);  // audio bitrate
        ast->codec->channels        = read_line_and_int(pb, &error);  // number of audio channels
        ast->codec->bits_per_sample = read_line_and_int(pb, &error);  // audio bits per sample
        // At least one sample uses 0 for ADPCM, which is really 4 bits
        // per sample.
        if (ast->codec->bits_per_sample == 0)
            ast->codec->bits_per_sample = 4;

        ast->codec->bit_rate = ast->codec->sample_rate *
                               ast->codec->bits_per_sample *
                               ast->codec->channels;

        ast->codec->codec_id = CODEC_ID_NONE;
        switch (audio_format) {
            case 1:
                if (ast->codec->bits_per_sample == 16) {
                    // 16-bit audio is always signed
                    ast->codec->codec_id = CODEC_ID_PCM_S16LE;
                    break;
                }
                // There are some other formats listed as legal per the spec;
                // samples needed.
                break;
            case 101:
                if (ast->codec->bits_per_sample == 8) {
                    // The samples with this kind of audio that I have
                    // are all unsigned.
                    ast->codec->codec_id = CODEC_ID_PCM_U8;
                    break;
                } else if (ast->codec->bits_per_sample == 4) {
                    ast->codec->codec_id = CODEC_ID_ADPCM_IMA_EA_SEAD;
                    break;
                }
                break;
        }
        if (ast->codec->codec_id == CODEC_ID_NONE) {
            av_log(s, AV_LOG_WARNING,
                   "RPL audio format %i not supported yet!\n",
                   audio_format);
        }
        av_set_pts_info(ast, 32, 1, ast->codec->bit_rate);
    } else {
        for (i = 0; i < 3; i++)
            error |= read_line(pb, line, sizeof(line));
    }

    rpl->frames_per_chunk = read_line_and_int(pb, &error);  // video frames per chunk
    if (rpl->frames_per_chunk > 1 && vst->codec->codec_tag != 124)
        av_log(s, AV_LOG_WARNING,
               "Don't know how to split frames for video format %i. "
               "Video stream will be broken!\n", vst->codec->codec_tag);

    number_of_chunks = read_line_and_int(pb, &error);  // number of chunks in the file
    // The number in the header is actually the index of the last chunk.
    number_of_chunks++;

    error |= read_line(pb, line, sizeof(line));  // "even" chunk size in bytes
    error |= read_line(pb, line, sizeof(line));  // "odd" chunk size in bytes
    chunk_catalog_offset =                       // offset of the "chunk catalog"
        read_line_and_int(pb, &error);           //   (file index)
    error |= read_line(pb, line, sizeof(line));  // offset to "helpful" sprite
    error |= read_line(pb, line, sizeof(line));  // size of "helpful" sprite
    error |= read_line(pb, line, sizeof(line));  // offset to key frame list

    // Read the index
    url_fseek(pb, chunk_catalog_offset, SEEK_SET);
    total_audio_size = 0;
    for (i = 0; i < number_of_chunks; i++) {
        int64_t offset, video_size, audio_size;
        error |= read_line(pb, line, sizeof(line));
        if (3 != sscanf(line, "%"PRId64" , %"PRId64" ; %"PRId64,
                        &offset, &video_size, &audio_size))
            error = -1;
        av_add_index_entry(vst, offset, i * rpl->frames_per_chunk,
                           video_size, rpl->frames_per_chunk, 0);
        if (ast)
            av_add_index_entry(ast, offset + video_size, total_audio_size,
                               audio_size, audio_size * 8, 0);
        total_audio_size += audio_size * 8;
    }

    if (error) return AVERROR(EIO);

    return 0;
}

static int rpl_read_packet(AVFormatContext *s, AVPacket *pkt)
{
    RPLContext *rpl = s->priv_data;
    ByteIOContext *pb = s->pb;
    AVStream* stream;
    AVIndexEntry* index_entry;
    uint32_t ret;

    if (rpl->chunk_part == s->nb_streams) {
        rpl->chunk_number++;
        rpl->chunk_part = 0;
    }

    stream = s->streams[rpl->chunk_part];

    if (rpl->chunk_number >= stream->nb_index_entries)
        return -1;

    index_entry = &stream->index_entries[rpl->chunk_number];

    if (rpl->frame_in_part == 0)
        if (url_fseek(pb, index_entry->pos, SEEK_SET) < 0)
            return AVERROR(EIO);

    if (stream->codec->codec_type == CODEC_TYPE_VIDEO &&
        stream->codec->codec_tag == 124) {
        // We have to split Escape 124 frames because there are
        // multiple frames per chunk in Escape 124 samples.
        uint32_t frame_size, frame_flags;

        frame_flags = get_le32(pb);
        frame_size = get_le32(pb);
        if (url_fseek(pb, -8, SEEK_CUR) < 0)
            return AVERROR(EIO);

        ret = av_get_packet(pb, pkt, frame_size);
        if (ret != frame_size) {
            av_free_packet(pkt);
            return AVERROR(EIO);
        }
        pkt->duration = 1;
        pkt->pts = index_entry->timestamp + rpl->frame_in_part;
        pkt->stream_index = rpl->chunk_part;

        rpl->frame_in_part++;
        if (rpl->frame_in_part == rpl->frames_per_chunk) {
            rpl->frame_in_part = 0;
            rpl->chunk_part++;
        }
    } else {
        ret = av_get_packet(pb, pkt, index_entry->size);
        if (ret != index_entry->size) {
            av_free_packet(pkt);
            return AVERROR(EIO);
        }

        if (stream->codec->codec_type == CODEC_TYPE_VIDEO) {
            // frames_per_chunk should always be one here; the header
            // parsing will warn if it isn't.
            pkt->duration = rpl->frames_per_chunk;
        } else {
            // All the audio codecs supported in this container
            // (at least so far) are constant-bitrate.
            pkt->duration = ret * 8;
        }
        pkt->pts = index_entry->timestamp;
        pkt->stream_index = rpl->chunk_part;
        rpl->chunk_part++;
    }

    // None of the Escape formats have keyframes, and the ADPCM
    // format used doesn't have keyframes.
    if (rpl->chunk_number == 0 && rpl->frame_in_part == 0)
        pkt->flags |= PKT_FLAG_KEY;

    return ret;
}

AVInputFormat rpl_demuxer = {
    "rpl",
    NULL_IF_CONFIG_SMALL("RPL/ARMovie format"),
    sizeof(RPLContext),
    rpl_probe,
    rpl_read_header,
    rpl_read_packet,
};