0683ad709b
As per https://web.archive.org/web/20020803104640/http://www.pcisys.net:80/~melanson/codecs/film-format.txt, the top bit of the info1 chunk is set as 1 for inter-coded frames and 0 otherwise.
399 lines
13 KiB
C
399 lines
13 KiB
C
/*
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* Sega FILM Format (CPK) Muxer
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* Copyright (C) 2003 The FFmpeg project
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* Copyright (C) 2018 Misty De Meo
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Sega FILM (.cpk) file muxer
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* @author Misty De Meo <misty@brew.sh>
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*
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* @see For more information regarding the Sega FILM file format, visit:
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* http://wiki.multimedia.cx/index.php?title=Sega_FILM
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*/
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#include "libavutil/intreadwrite.h"
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#include "avformat.h"
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#include "internal.h"
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#include "avio_internal.h"
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typedef struct FILMPacket {
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int audio;
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int keyframe;
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int32_t pts;
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int32_t duration;
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int32_t size;
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int32_t index;
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struct FILMPacket *next;
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} FILMPacket;
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typedef struct FILMOutputContext {
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const AVClass *class;
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int audio_index;
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int video_index;
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int64_t stab_pos;
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FILMPacket *start;
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FILMPacket *last;
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int64_t packet_count;
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} FILMOutputContext;
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static int film_write_packet_to_header(AVFormatContext *format_context, FILMPacket *pkt)
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{
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AVIOContext *pb = format_context->pb;
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/* The bits in these two 32-bit integers contain info about the contents of this sample */
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int32_t info1 = 0;
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int32_t info2 = 0;
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if (pkt->audio) {
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/* Always the same, carries no more information than "this is audio" */
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info1 = 0xFFFFFFFF;
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info2 = 1;
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} else {
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info1 = pkt->pts;
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info2 = pkt->duration;
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/* The top bit being set indicates a key frame */
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if (!pkt->keyframe)
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info1 |= (1 << 31);
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}
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/* Write the 16-byte sample info packet to the STAB chunk in the header */
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avio_wb32(pb, pkt->index);
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avio_wb32(pb, pkt->size);
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avio_wb32(pb, info1);
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avio_wb32(pb, info2);
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return 0;
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}
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static int film_write_packet(AVFormatContext *format_context, AVPacket *pkt)
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{
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FILMPacket *metadata;
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AVIOContext *pb = format_context->pb;
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FILMOutputContext *film = format_context->priv_data;
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int encoded_buf_size = 0;
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enum AVCodecID codec_id;
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/* Track the metadata used to write the header and add it to the linked list */
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metadata = av_mallocz(sizeof(FILMPacket));
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if (!metadata)
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return AVERROR(ENOMEM);
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metadata->audio = pkt->stream_index == film->audio_index;
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metadata->keyframe = pkt->flags & AV_PKT_FLAG_KEY;
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metadata->pts = pkt->pts;
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metadata->duration = pkt->duration;
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metadata->size = pkt->size;
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if (film->last == NULL) {
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metadata->index = 0;
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} else {
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metadata->index = film->last->index + film->last->size;
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film->last->next = metadata;
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}
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metadata->next = NULL;
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if (film->start == NULL)
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film->start = metadata;
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film->packet_count++;
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film->last = metadata;
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codec_id = format_context->streams[pkt->stream_index]->codecpar->codec_id;
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/* Sega Cinepak has an extra two-byte header; write dummy data there,
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* then adjust the cvid header to accommodate for the extra size */
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if (codec_id == AV_CODEC_ID_CINEPAK) {
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encoded_buf_size = AV_RB24(&pkt->data[1]);
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/* Already Sega Cinepak, so no need to reformat the packets */
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if (encoded_buf_size != pkt->size && (pkt->size % encoded_buf_size) != 0) {
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avio_write(pb, pkt->data, pkt->size);
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} else {
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uint8_t padding[2] = {0, 0};
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/* In Sega Cinepak, the reported size in the Cinepak header is
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* 8 bytes too short. However, the size in the STAB section of the header
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* is correct, taking into account the extra two bytes. */
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AV_WB24(&pkt->data[1], pkt->size - 8 + 2);
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metadata->size += 2;
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avio_write(pb, pkt->data, 10);
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avio_write(pb, padding, 2);
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avio_write(pb, &pkt->data[10], pkt->size - 10);
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}
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} else {
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/* Other formats can just be written as-is */
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avio_write(pb, pkt->data, pkt->size);
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}
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return 0;
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}
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static int get_audio_codec_id(enum AVCodecID codec_id)
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{
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/* 0 (PCM) and 2 (ADX) are the only known values */
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switch (codec_id) {
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case AV_CODEC_ID_PCM_S8_PLANAR:
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case AV_CODEC_ID_PCM_S16BE_PLANAR:
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return 0;
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break;
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case AV_CODEC_ID_ADPCM_ADX:
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return 2;
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break;
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default:
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return -1;
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}
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}
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static int film_init(AVFormatContext *format_context)
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{
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AVStream *audio = NULL;
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FILMOutputContext *film = format_context->priv_data;
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film->audio_index = -1;
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film->video_index = -1;
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film->stab_pos = 0;
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film->packet_count = 0;
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film->start = NULL;
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film->last = NULL;
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for (int i = 0; i < format_context->nb_streams; i++) {
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AVStream *st = format_context->streams[i];
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if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
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if (film->audio_index > -1) {
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av_log(format_context, AV_LOG_ERROR, "Sega FILM allows a maximum of one audio stream.\n");
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return AVERROR(EINVAL);
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}
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film->audio_index = i;
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audio = st;
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}
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if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
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if (film->video_index > -1) {
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av_log(format_context, AV_LOG_ERROR, "Sega FILM allows a maximum of one video stream.\n");
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return AVERROR(EINVAL);
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}
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film->video_index = i;
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}
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if (film->video_index == -1) {
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av_log(format_context, AV_LOG_ERROR, "No video stream present.\n");
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return AVERROR(EINVAL);
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}
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}
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if (audio != NULL && get_audio_codec_id(audio->codecpar->codec_id) < 0) {
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av_log(format_context, AV_LOG_ERROR, "Incompatible audio stream format.\n");
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return AVERROR(EINVAL);
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}
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return 0;
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}
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static int shift_data(AVFormatContext *format_context, int64_t shift_size)
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{
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int ret = 0;
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int64_t pos, pos_end = avio_tell(format_context->pb);
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uint8_t *buf, *read_buf[2];
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int read_buf_id = 0;
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int read_size[2];
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AVIOContext *read_pb;
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buf = av_malloc(shift_size * 2);
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if (!buf)
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return AVERROR(ENOMEM);
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read_buf[0] = buf;
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read_buf[1] = buf + shift_size;
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/* Write the header at the beginning of the file, shifting all content as necessary;
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* based on the approach used by MOV faststart. */
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avio_flush(format_context->pb);
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ret = format_context->io_open(format_context, &read_pb, format_context->url, AVIO_FLAG_READ, NULL);
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if (ret < 0) {
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av_log(format_context, AV_LOG_ERROR, "Unable to re-open %s output file to "
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"write the header\n", format_context->url);
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av_free(buf);
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return ret;
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}
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/* mark the end of the shift to up to the last data we wrote, and get ready
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* for writing */
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pos_end = avio_tell(format_context->pb);
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avio_seek(format_context->pb, shift_size, SEEK_SET);
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/* start reading at where the new header will be placed */
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avio_seek(read_pb, 0, SEEK_SET);
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pos = avio_tell(read_pb);
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#define READ_BLOCK do { \
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read_size[read_buf_id] = avio_read(read_pb, read_buf[read_buf_id], shift_size); \
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read_buf_id ^= 1; \
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} while (0)
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/* shift data by chunk of at most shift_size */
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READ_BLOCK;
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do {
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int n;
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READ_BLOCK;
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n = read_size[read_buf_id];
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if (n <= 0)
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break;
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avio_write(format_context->pb, read_buf[read_buf_id], n);
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pos += n;
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} while (pos < pos_end);
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ff_format_io_close(format_context, &read_pb);
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av_free(buf);
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return 0;
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}
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static int film_write_header(AVFormatContext *format_context)
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{
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int ret = 0;
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int64_t sample_table_size, stabsize, headersize;
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int8_t audio_codec;
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AVIOContext *pb = format_context->pb;
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FILMOutputContext *film = format_context->priv_data;
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FILMPacket *prev, *packet;
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AVStream *audio = NULL;
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AVStream *video = NULL;
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/* Calculate how much we need to reserve for the header;
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* this is the amount the rest of the data will be shifted up by. */
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sample_table_size = film->packet_count * 16;
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stabsize = 16 + sample_table_size;
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headersize = 16 + /* FILM header base */
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32 + /* FDSC chunk */
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stabsize;
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ret = shift_data(format_context, headersize);
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if (ret < 0)
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return ret;
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/* Seek back to the beginning to start writing the header now */
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avio_seek(pb, 0, SEEK_SET);
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if (film->audio_index > -1)
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audio = format_context->streams[film->audio_index];
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if (film->video_index > -1)
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video = format_context->streams[film->video_index];
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if (audio != NULL) {
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audio_codec = get_audio_codec_id(audio->codecpar->codec_id);
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if (audio_codec < 0) {
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av_log(format_context, AV_LOG_ERROR, "Incompatible audio stream format.\n");
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return AVERROR(EINVAL);
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}
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}
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if (video->codecpar->format != AV_PIX_FMT_RGB24) {
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av_log(format_context, AV_LOG_ERROR, "Pixel format must be rgb24.\n");
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return AVERROR(EINVAL);
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}
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/* First, write the FILM header; this is very simple */
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ffio_wfourcc(pb, "FILM");
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avio_wb32(pb, 48 + stabsize);
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/* This seems to be okay to hardcode, since this muxer targets 1.09 features;
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* videos produced by this muxer are readable by 1.08 and lower players. */
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ffio_wfourcc(pb, "1.09");
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/* I have no idea what this field does, might be reserved */
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avio_wb32(pb, 0);
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/* Next write the FDSC (file description) chunk */
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ffio_wfourcc(pb, "FDSC");
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avio_wb32(pb, 0x20); /* Size of FDSC chunk */
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/* The only two supported codecs; raw video is rare */
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switch (video->codecpar->codec_id) {
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case AV_CODEC_ID_CINEPAK:
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ffio_wfourcc(pb, "cvid");
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break;
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case AV_CODEC_ID_RAWVIDEO:
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ffio_wfourcc(pb, "raw ");
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break;
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default:
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av_log(format_context, AV_LOG_ERROR, "Incompatible video stream format.\n");
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return AVERROR(EINVAL);
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}
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avio_wb32(pb, video->codecpar->height);
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avio_wb32(pb, video->codecpar->width);
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avio_w8(pb, 24); /* Bits per pixel - observed to always be 24 */
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if (audio != NULL) {
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avio_w8(pb, audio->codecpar->channels); /* Audio channels */
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avio_w8(pb, audio->codecpar->bits_per_coded_sample); /* Audio bit depth */
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avio_w8(pb, audio_codec); /* Compression - 0 is PCM, 2 is ADX */
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avio_wb16(pb, audio->codecpar->sample_rate); /* Audio sampling rate */
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} else {
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/* Set all these fields to 0 if there's no audio */
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avio_w8(pb, 0);
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avio_w8(pb, 0);
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avio_w8(pb, 0);
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avio_wb16(pb, 0);
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}
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/* I have no idea what this pair of fields does either, might be reserved */
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avio_wb32(pb, 0);
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avio_wb16(pb, 0);
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/* Finally, write the STAB (sample table) chunk */
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ffio_wfourcc(pb, "STAB");
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avio_wb32(pb, 16 + (film->packet_count * 16));
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/* Framerate base frequency. Here we're assuming that the frame rate is even.
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* In real world Sega FILM files, there are usually a couple of approaches:
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* a) framerate base frequency is the same as the framerate, and ticks
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* increment by 1 every frame, or
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* b) framerate base frequency is a much larger number, and ticks
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* increment by larger steps every frame.
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* The latter occurs even in cases where the frame rate is even; for example, in
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* Lunar: Silver Star Story, the base frequency is 600 and each frame, the ticks
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* are incremented by 25 for an evenly spaced framerate of 24fps. */
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avio_wb32(pb, av_q2d(av_inv_q(video->time_base)));
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avio_wb32(pb, film->packet_count);
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avio_flush(pb);
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/* Finally, write out each packet's data to the header */
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packet = film->start;
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while (packet != NULL) {
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film_write_packet_to_header(format_context, packet);
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prev = packet;
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packet = packet->next;
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av_freep(&prev);
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}
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return 0;
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}
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static const AVClass film_muxer_class = {
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.class_name = "Sega FILM muxer",
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.item_name = av_default_item_name,
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.version = LIBAVUTIL_VERSION_INT,
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};
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AVOutputFormat ff_segafilm_muxer = {
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.name = "film_cpk",
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.long_name = NULL_IF_CONFIG_SMALL("Sega FILM / CPK"),
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.extensions = "cpk",
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.priv_data_size = sizeof(FILMOutputContext),
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.audio_codec = AV_CODEC_ID_PCM_S16BE_PLANAR,
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.video_codec = AV_CODEC_ID_CINEPAK,
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.init = film_init,
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.write_trailer = film_write_header,
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.write_packet = film_write_packet,
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.priv_class = &film_muxer_class,
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};
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