FFmpeg/libavformat/bethsoftvid.c

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/*
* Bethsoft VID format Demuxer
* Copyright (c) 2007 Nicholas Tung
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* @brief Bethesda Softworks VID (.vid) file demuxer
* @author Nicholas Tung [ntung (at. ntung com] (2007-03)
* @see http://wiki.multimedia.cx/index.php?title=Bethsoft_VID
* @see http://www.svatopluk.com/andux/docs/dfvid.html
*/
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#include "libavutil/channel_layout.h"
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
#include "libavcodec/bethsoftvideo.h"
#define BVID_PALETTE_SIZE 3 * 256
#define DEFAULT_SAMPLE_RATE 11111
typedef struct BVID_DemuxContext
{
int nframes;
int sample_rate; /**< audio sample rate */
int width; /**< video width */
int height; /**< video height */
/** delay value between frames, added to individual frame delay.
* custom units, which will be added to other custom units (~=16ms according
* to free, unofficial documentation) */
int bethsoft_global_delay;
int video_index; /**< video stream index */
int audio_index; /**< audio stream index */
uint8_t *palette;
int is_finished;
} BVID_DemuxContext;
static int vid_probe(AVProbeData *p)
{
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// little-endian VID tag, file starts with "VID\0"
if (AV_RL32(p->buf) != MKTAG('V', 'I', 'D', 0))
return 0;
return AVPROBE_SCORE_MAX;
}
static int vid_read_header(AVFormatContext *s)
{
BVID_DemuxContext *vid = s->priv_data;
AVIOContext *pb = s->pb;
/* load main header. Contents:
* bytes: 'V' 'I' 'D'
* int16s: always_512, nframes, width, height, delay, always_14
*/
avio_skip(pb, 5);
vid->nframes = avio_rl16(pb);
vid->width = avio_rl16(pb);
vid->height = avio_rl16(pb);
vid->bethsoft_global_delay = avio_rl16(pb);
avio_rl16(pb);
// wait until the first packet to create each stream
vid->video_index = -1;
vid->audio_index = -1;
vid->sample_rate = DEFAULT_SAMPLE_RATE;
s->ctx_flags |= AVFMTCTX_NOHEADER;
return 0;
}
#define BUFFER_PADDING_SIZE 1000
static int read_frame(BVID_DemuxContext *vid, AVIOContext *pb, AVPacket *pkt,
uint8_t block_type, AVFormatContext *s)
{
uint8_t * vidbuf_start = NULL;
int vidbuf_nbytes = 0;
int code;
int bytes_copied = 0;
int position, duration, npixels;
unsigned int vidbuf_capacity;
int ret = 0;
AVStream *st;
if (vid->video_index < 0) {
st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
vid->video_index = st->index;
if (vid->audio_index < 0) {
avpriv_request_sample(s, "Using default video time base since "
"having no audio packet before the first "
"video packet");
}
avpriv_set_pts_info(st, 64, 185, vid->sample_rate);
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
st->codecpar->codec_id = AV_CODEC_ID_BETHSOFTVID;
st->codecpar->width = vid->width;
st->codecpar->height = vid->height;
}
st = s->streams[vid->video_index];
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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npixels = st->codecpar->width * st->codecpar->height;
vidbuf_start = av_malloc(vidbuf_capacity = BUFFER_PADDING_SIZE);
if(!vidbuf_start)
return AVERROR(ENOMEM);
// save the file position for the packet, include block type
position = avio_tell(pb) - 1;
vidbuf_start[vidbuf_nbytes++] = block_type;
// get the current packet duration
duration = vid->bethsoft_global_delay + avio_rl16(pb);
// set the y offset if it exists (decoder header data should be in data section)
if(block_type == VIDEO_YOFF_P_FRAME){
if (avio_read(pb, &vidbuf_start[vidbuf_nbytes], 2) != 2) {
ret = AVERROR(EIO);
goto fail;
}
vidbuf_nbytes += 2;
}
do{
vidbuf_start = av_fast_realloc(vidbuf_start, &vidbuf_capacity, vidbuf_nbytes + BUFFER_PADDING_SIZE);
if(!vidbuf_start)
return AVERROR(ENOMEM);
code = avio_r8(pb);
vidbuf_start[vidbuf_nbytes++] = code;
if(code >= 0x80){ // rle sequence
if(block_type == VIDEO_I_FRAME)
vidbuf_start[vidbuf_nbytes++] = avio_r8(pb);
} else if(code){ // plain sequence
if (avio_read(pb, &vidbuf_start[vidbuf_nbytes], code) != code) {
ret = AVERROR(EIO);
goto fail;
}
vidbuf_nbytes += code;
}
bytes_copied += code & 0x7F;
if(bytes_copied == npixels){ // sometimes no stop character is given, need to keep track of bytes copied
// may contain a 0 byte even if read all pixels
if(avio_r8(pb))
avio_seek(pb, -1, SEEK_CUR);
break;
}
if (bytes_copied > npixels) {
ret = AVERROR_INVALIDDATA;
goto fail;
}
} while(code);
// copy data into packet
if ((ret = av_new_packet(pkt, vidbuf_nbytes)) < 0)
goto fail;
memcpy(pkt->data, vidbuf_start, vidbuf_nbytes);
pkt->pos = position;
pkt->stream_index = vid->video_index;
pkt->duration = duration;
if (block_type == VIDEO_I_FRAME)
pkt->flags |= AV_PKT_FLAG_KEY;
/* if there is a new palette available, add it to packet side data */
if (vid->palette) {
uint8_t *pdata = av_packet_new_side_data(pkt, AV_PKT_DATA_PALETTE,
BVID_PALETTE_SIZE);
if (!pdata) {
ret = AVERROR(ENOMEM);
goto fail;
}
memcpy(pdata, vid->palette, BVID_PALETTE_SIZE);
av_freep(&vid->palette);
}
vid->nframes--; // used to check if all the frames were read
fail:
av_free(vidbuf_start);
return ret;
}
static int vid_read_packet(AVFormatContext *s,
AVPacket *pkt)
{
BVID_DemuxContext *vid = s->priv_data;
AVIOContext *pb = s->pb;
unsigned char block_type;
int audio_length;
int ret_value;
if(vid->is_finished || pb->eof_reached)
return AVERROR(EIO);
block_type = avio_r8(pb);
switch(block_type){
case PALETTE_BLOCK:
if (vid->palette) {
av_log(s, AV_LOG_WARNING, "discarding unused palette\n");
av_freep(&vid->palette);
}
vid->palette = av_malloc(BVID_PALETTE_SIZE);
if (!vid->palette)
return AVERROR(ENOMEM);
if (avio_read(pb, vid->palette, BVID_PALETTE_SIZE) != BVID_PALETTE_SIZE) {
av_freep(&vid->palette);
return AVERROR(EIO);
}
return vid_read_packet(s, pkt);
case FIRST_AUDIO_BLOCK:
avio_rl16(pb);
// soundblaster DAC used for sample rate, as on specification page (link above)
vid->sample_rate = 1000000 / (256 - avio_r8(pb));
case AUDIO_BLOCK:
if (vid->audio_index < 0) {
AVStream *st = avformat_new_stream(s, NULL);
if (!st)
return AVERROR(ENOMEM);
vid->audio_index = st->index;
lavf: replace AVStream.codec with AVStream.codecpar Currently, AVStream contains an embedded AVCodecContext instance, which is used by demuxers to export stream parameters to the caller and by muxers to receive stream parameters from the caller. It is also used internally as the codec context that is passed to parsers. In addition, it is also widely used by the callers as the decoding (when demuxer) or encoding (when muxing) context, though this has been officially discouraged since Libav 11. There are multiple important problems with this approach: - the fields in AVCodecContext are in general one of * stream parameters * codec options * codec state However, it's not clear which ones are which. It is consequently unclear which fields are a demuxer allowed to set or a muxer allowed to read. This leads to erratic behaviour depending on whether decoding or encoding is being performed or not (and whether it uses the AVStream embedded codec context). - various synchronization issues arising from the fact that the same context is used by several different APIs (muxers/demuxers, parsers, bitstream filters and encoders/decoders) simultaneously, with there being no clear rules for who can modify what and the different processes being typically delayed with respect to each other. - avformat_find_stream_info() making it necessary to support opening and closing a single codec context multiple times, thus complicating the semantics of freeing various allocated objects in the codec context. Those problems are resolved by replacing the AVStream embedded codec context with a newly added AVCodecParameters instance, which stores only the stream parameters exported by the demuxers or read by the muxers.
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st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
st->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
st->codecpar->channels = 1;
st->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
st->codecpar->bits_per_coded_sample = 8;
st->codecpar->sample_rate = vid->sample_rate;
st->codecpar->bit_rate = 8 * st->codecpar->sample_rate;
st->start_time = 0;
avpriv_set_pts_info(st, 64, 1, vid->sample_rate);
}
audio_length = avio_rl16(pb);
if ((ret_value = av_get_packet(pb, pkt, audio_length)) != audio_length) {
if (ret_value < 0)
return ret_value;
av_log(s, AV_LOG_ERROR, "incomplete audio block\n");
return AVERROR(EIO);
}
pkt->stream_index = vid->audio_index;
pkt->duration = audio_length;
pkt->flags |= AV_PKT_FLAG_KEY;
return 0;
case VIDEO_P_FRAME:
case VIDEO_YOFF_P_FRAME:
case VIDEO_I_FRAME:
return read_frame(vid, pb, pkt, block_type, s);
case EOF_BLOCK:
if(vid->nframes != 0)
av_log(s, AV_LOG_VERBOSE, "reached terminating character but not all frames read.\n");
vid->is_finished = 1;
return AVERROR(EIO);
default:
av_log(s, AV_LOG_ERROR, "unknown block (character = %c, decimal = %d, hex = %x)!!!\n",
block_type, block_type, block_type);
return AVERROR_INVALIDDATA;
}
}
static int vid_read_close(AVFormatContext *s)
{
BVID_DemuxContext *vid = s->priv_data;
av_freep(&vid->palette);
return 0;
}
AVInputFormat ff_bethsoftvid_demuxer = {
.name = "bethsoftvid",
.long_name = NULL_IF_CONFIG_SMALL("Bethesda Softworks VID"),
.priv_data_size = sizeof(BVID_DemuxContext),
.read_probe = vid_probe,
.read_header = vid_read_header,
.read_packet = vid_read_packet,
.read_close = vid_read_close,
};