ffmpeg/libavformat/segafilmenc.c

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/*
* Sega FILM Format (CPK) Muxer
* Copyright (C) 2003 The FFmpeg project
* Copyright (C) 2018 Misty De Meo
*
* 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
*/
/**
* @file
* Sega FILM (.cpk) file muxer
* @author Misty De Meo <misty@brew.sh>
*
* @see For more information regarding the Sega FILM file format, visit:
* http://wiki.multimedia.cx/index.php?title=Sega_FILM
*/
#include "libavutil/avassert.h"
#include "libavutil/intreadwrite.h"
#include "libavcodec/bytestream.h"
#include "avformat.h"
#include "internal.h"
#include "avio_internal.h"
typedef struct FILMOutputContext {
AVIOContext *header;
unsigned index;
int audio_index;
int video_index;
} FILMOutputContext;
static int film_write_packet(AVFormatContext *format_context, AVPacket *pkt)
{
AVIOContext *pb = format_context->pb;
FILMOutputContext *film = format_context->priv_data;
int encoded_buf_size, size = pkt->size;
uint32_t info1, info2;
enum AVCodecID codec_id;
codec_id = format_context->streams[pkt->stream_index]->codecpar->codec_id;
/* Sega Cinepak has an extra two-byte header; write dummy data there,
* then adjust the cvid header to accommodate for the extra size */
if (codec_id == AV_CODEC_ID_CINEPAK) {
encoded_buf_size = AV_RB24(&pkt->data[1]);
/* Already Sega Cinepak, so no need to reformat the packets */
if (encoded_buf_size != pkt->size && (pkt->size % encoded_buf_size) != 0) {
avio_write(pb, pkt->data, pkt->size);
} else {
/* In Sega Cinepak, the reported size in the Cinepak header is
* 8 bytes too short. However, the size in the STAB section of the header
* is correct, taking into account the extra two bytes. */
AV_WB24(&pkt->data[1], pkt->size - 8 + 2);
size += 2;
avio_write(pb, pkt->data, 10);
avio_wb16(pb, 0);
avio_write(pb, &pkt->data[10], pkt->size - 10);
}
} else {
/* Other formats can just be written as-is */
avio_write(pb, pkt->data, pkt->size);
}
/* Add the 16-byte sample info entry to the dynamic buffer
* for the STAB chunk in the header */
pb = film->header;
avio_wb32(pb, film->index);
film->index += size;
avio_wb32(pb, size);
if (film->audio_index == pkt->stream_index) {
/* Always the same, carries no more information than "this is audio" */
info1 = 0xFFFFFFFF;
info2 = 1;
} else {
info1 = pkt->pts;
info2 = pkt->duration;
/* The top bit being set indicates a key frame */
if (!(pkt->flags & AV_PKT_FLAG_KEY))
info1 |= 1U << 31;
}
avio_wb32(pb, info1);
avio_wb32(pb, info2);
return pb->error;
}
static int get_audio_codec_id(enum AVCodecID codec_id)
{
/* 0 (PCM) and 2 (ADX) are the only known values */
switch (codec_id) {
case AV_CODEC_ID_PCM_S8_PLANAR:
case AV_CODEC_ID_PCM_S16BE_PLANAR:
return 0;
case AV_CODEC_ID_ADPCM_ADX:
return 2;
default:
return -1;
}
}
static int film_init(AVFormatContext *format_context)
{
FILMOutputContext *film = format_context->priv_data;
int ret;
film->audio_index = -1;
film->video_index = -1;
for (int i = 0; i < format_context->nb_streams; i++) {
AVStream *st = format_context->streams[i];
if (st->codecpar->codec_type == AVMEDIA_TYPE_AUDIO) {
if (film->audio_index > -1) {
av_log(format_context, AV_LOG_ERROR, "Sega FILM allows a maximum of one audio stream.\n");
return AVERROR(EINVAL);
}
if (get_audio_codec_id(st->codecpar->codec_id) < 0) {
av_log(format_context, AV_LOG_ERROR,
"Incompatible audio stream format.\n");
return AVERROR(EINVAL);
}
film->audio_index = i;
}
if (st->codecpar->codec_type == AVMEDIA_TYPE_VIDEO) {
if (film->video_index > -1) {
av_log(format_context, AV_LOG_ERROR, "Sega FILM allows a maximum of one video stream.\n");
return AVERROR(EINVAL);
}
if (st->codecpar->codec_id != AV_CODEC_ID_CINEPAK &&
st->codecpar->codec_id != AV_CODEC_ID_RAWVIDEO) {
av_log(format_context, AV_LOG_ERROR,
"Incompatible video stream format.\n");
return AVERROR(EINVAL);
}
if (st->codecpar->format != AV_PIX_FMT_RGB24) {
av_log(format_context, AV_LOG_ERROR,
"Pixel format must be rgb24.\n");
return AVERROR(EINVAL);
}
film->video_index = i;
}
}
if (film->video_index == -1) {
av_log(format_context, AV_LOG_ERROR, "No video stream present.\n");
return AVERROR(EINVAL);
}
if ((ret = avio_open_dyn_buf(&film->header)) < 0)
return ret;
ffio_fill(film->header, 0, 16 + 32 + 16);
return 0;
}
static int write_header(AVFormatContext *format_context, uint8_t *header,
unsigned header_size)
{
int ret = ff_format_shift_data(format_context, 0, header_size);
if (ret < 0)
return ret;
avio_seek(format_context->pb, 0, SEEK_SET);
avio_write(format_context->pb, header, header_size);
return 0;
}
static int film_write_header(AVFormatContext *format_context)
{
int ret = 0;
unsigned stabsize, headersize, packet_count;
FILMOutputContext *film = format_context->priv_data;
AVStream *video = NULL;
uint8_t *header, *ptr;
/* Calculate how much we need to reserve for the header;
* this is the amount the rest of the data will be shifted up by. */
headersize = avio_get_dyn_buf(film->header, &header);
if (headersize < 64) {
av_assert1(film->header->error < 0);
return film->header->error;
}
packet_count = (headersize - 64) / 16;
stabsize = 16 + 16 * packet_count;
headersize = 16 + /* FILM header base */
32 + /* FDSC chunk */
stabsize;
/* Write the header at the position in the buffer reserved for it.
* First, write the FILM header; this is very simple */
ptr = header;
bytestream_put_be32(&ptr, MKBETAG('F', 'I', 'L', 'M'));
bytestream_put_be32(&ptr, headersize);
/* This seems to be okay to hardcode, since this muxer targets 1.09 features;
* videos produced by this muxer are readable by 1.08 and lower players. */
bytestream_put_be32(&ptr, MKBETAG('1', '.', '0', '9'));
/* I have no idea what the next four bytes do, might be reserved */
ptr += 4;
/* Next write the FDSC (file description) chunk */
bytestream_put_be32(&ptr, MKBETAG('F', 'D', 'S', 'C'));
bytestream_put_be32(&ptr, 0x20); /* Size of FDSC chunk */
video = format_context->streams[film->video_index];
/* The only two supported codecs; raw video is rare */
switch (video->codecpar->codec_id) {
case AV_CODEC_ID_CINEPAK:
bytestream_put_be32(&ptr, MKBETAG('c', 'v', 'i', 'd'));
break;
case AV_CODEC_ID_RAWVIDEO:
bytestream_put_be32(&ptr, MKBETAG('r', 'a', 'w', ' '));
break;
}
bytestream_put_be32(&ptr, video->codecpar->height);
bytestream_put_be32(&ptr, video->codecpar->width);
bytestream_put_byte(&ptr, 24); /* Bits per pixel - observed to always be 24 */
if (film->audio_index > -1) {
AVStream *audio = format_context->streams[film->audio_index];
int audio_codec = get_audio_codec_id(audio->codecpar->codec_id);
bytestream_put_byte(&ptr, audio->codecpar->channels); /* Audio channels */
bytestream_put_byte(&ptr, audio->codecpar->bits_per_coded_sample); /* Audio bit depth */
bytestream_put_byte(&ptr, audio_codec); /* Compression - 0 is PCM, 2 is ADX */
bytestream_put_be16(&ptr, audio->codecpar->sample_rate); /* Audio sampling rate */
} else {
/* If there is no audio, all the audio fields should be set to zero.
* ffio_fill() already did this for us. */
ptr += 1 + 1 + 1 + 2;
}
/* I have no idea what this pair of fields does either, might be reserved */
ptr += 4 + 2;
/* Finally, write the STAB (sample table) chunk */
bytestream_put_be32(&ptr, MKBETAG('S', 'T', 'A', 'B'));
bytestream_put_be32(&ptr, stabsize);
/* Framerate base frequency. Here we're assuming that the frame rate is even.
* In real world Sega FILM files, there are usually a couple of approaches:
* a) framerate base frequency is the same as the framerate, and ticks
* increment by 1 every frame, or
* b) framerate base frequency is a much larger number, and ticks
* increment by larger steps every frame.
* The latter occurs even in cases where the frame rate is even; for example, in
* Lunar: Silver Star Story, the base frequency is 600 and each frame, the ticks
* are incremented by 25 for an evenly spaced framerate of 24fps. */
bytestream_put_be32(&ptr, av_q2d(av_inv_q(video->time_base)));
bytestream_put_be32(&ptr, packet_count);
/* Finally, shift the data and write out the header. */
ret = write_header(format_context, header, headersize);
if (ret < 0)
return ret;
return 0;
}
static void film_deinit(AVFormatContext *format_context)
{
FILMOutputContext *film = format_context->priv_data;
ffio_free_dyn_buf(&film->header);
}
const AVOutputFormat ff_segafilm_muxer = {
.name = "film_cpk",
.long_name = NULL_IF_CONFIG_SMALL("Sega FILM / CPK"),
.extensions = "cpk",
.priv_data_size = sizeof(FILMOutputContext),
.audio_codec = AV_CODEC_ID_PCM_S16BE_PLANAR,
.video_codec = AV_CODEC_ID_CINEPAK,
.init = film_init,
.write_trailer = film_write_header,
.write_packet = film_write_packet,
.deinit = film_deinit,
};