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FFmpeg/libavformat/bfi.c

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/*
* Brute Force & Ignorance (BFI) demuxer
* Copyright (c) 2008 Sisir Koppaka
*
* 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
* @brief Brute Force & Ignorance (.bfi) file demuxer
* @author Sisir Koppaka ( sisir.koppaka at gmail dot com )
* @see http://wiki.multimedia.cx/index.php?title=BFI
*/
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#include "libavutil/channel_layout.h"
#include "libavutil/intreadwrite.h"
#include "avformat.h"
#include "internal.h"
typedef struct BFIContext {
int nframes;
int audio_frame;
int video_frame;
int video_size;
int avflag;
} BFIContext;
static int bfi_probe(const AVProbeData * p)
{
/* Check file header */
if (AV_RL32(p->buf) == MKTAG('B', 'F', '&', 'I'))
return AVPROBE_SCORE_MAX;
else
return 0;
}
static int bfi_read_header(AVFormatContext * s)
{
BFIContext *bfi = s->priv_data;
AVIOContext *pb = s->pb;
AVStream *vstream;
AVStream *astream;
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int ret, fps, chunk_header;
/* Initialize the video codec... */
vstream = avformat_new_stream(s, NULL);
if (!vstream)
return AVERROR(ENOMEM);
/* Initialize the audio codec... */
astream = avformat_new_stream(s, NULL);
if (!astream)
return AVERROR(ENOMEM);
/* Set the total number of frames. */
avio_skip(pb, 8);
chunk_header = avio_rl32(pb);
bfi->nframes = avio_rl32(pb);
avio_rl32(pb);
avio_rl32(pb);
avio_rl32(pb);
fps = avio_rl32(pb);
avio_skip(pb, 12);
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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vstream->codecpar->width = avio_rl32(pb);
vstream->codecpar->height = avio_rl32(pb);
/*Load the palette to extradata */
avio_skip(pb, 8);
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ret = ff_get_extradata(s, vstream->codecpar, pb, 768);
if (ret < 0)
return ret;
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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astream->codecpar->sample_rate = avio_rl32(pb);
if (astream->codecpar->sample_rate <= 0) {
av_log(s, AV_LOG_ERROR, "Invalid sample rate %d\n", astream->codecpar->sample_rate);
return AVERROR_INVALIDDATA;
}
/* Set up the video codec... */
avpriv_set_pts_info(vstream, 32, 1, fps);
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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vstream->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
vstream->codecpar->codec_id = AV_CODEC_ID_BFI;
vstream->codecpar->format = AV_PIX_FMT_PAL8;
vstream->nb_frames =
vstream->duration = bfi->nframes;
/* Set up the audio codec now... */
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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astream->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
astream->codecpar->codec_id = AV_CODEC_ID_PCM_U8;
astream->codecpar->channels = 1;
astream->codecpar->channel_layout = AV_CH_LAYOUT_MONO;
astream->codecpar->bits_per_coded_sample = 8;
astream->codecpar->bit_rate =
(int64_t)astream->codecpar->sample_rate * astream->codecpar->bits_per_coded_sample;
avio_seek(pb, chunk_header - 3, SEEK_SET);
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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avpriv_set_pts_info(astream, 64, 1, astream->codecpar->sample_rate);
return 0;
}
static int bfi_read_packet(AVFormatContext * s, AVPacket * pkt)
{
BFIContext *bfi = s->priv_data;
AVIOContext *pb = s->pb;
int ret, audio_offset, video_offset, chunk_size, audio_size = 0;
if (bfi->nframes == 0 || avio_feof(pb)) {
return AVERROR_EOF;
}
/* If all previous chunks were completely read, then find a new one... */
if (!bfi->avflag) {
uint32_t state = 0;
while(state != MKTAG('S','A','V','I')){
if (avio_feof(pb))
return AVERROR(EIO);
state = 256*state + avio_r8(pb);
}
/* Now that the chunk's location is confirmed, we proceed... */
chunk_size = avio_rl32(pb);
avio_rl32(pb);
audio_offset = avio_rl32(pb);
avio_rl32(pb);
video_offset = avio_rl32(pb);
audio_size = video_offset - audio_offset;
bfi->video_size = chunk_size - video_offset;
if (audio_size < 0 || bfi->video_size < 0) {
av_log(s, AV_LOG_ERROR, "Invalid audio/video offsets or chunk size\n");
return AVERROR_INVALIDDATA;
}
//Tossing an audio packet at the audio decoder.
ret = av_get_packet(pb, pkt, audio_size);
if (ret < 0)
return ret;
pkt->pts = bfi->audio_frame;
bfi->audio_frame += ret;
} else if (bfi->video_size > 0) {
//Tossing a video packet at the video decoder.
ret = av_get_packet(pb, pkt, bfi->video_size);
if (ret < 0)
return ret;
pkt->pts = bfi->video_frame;
bfi->video_frame += ret / bfi->video_size;
/* One less frame to read. A cursory decrement. */
bfi->nframes--;
} else {
/* Empty video packet */
ret = AVERROR(EAGAIN);
}
bfi->avflag = !bfi->avflag;
pkt->stream_index = bfi->avflag;
return ret;
}
AVInputFormat ff_bfi_demuxer = {
.name = "bfi",
.long_name = NULL_IF_CONFIG_SMALL("Brute Force & Ignorance"),
.priv_data_size = sizeof(BFIContext),
.read_probe = bfi_probe,
.read_header = bfi_read_header,
.read_packet = bfi_read_packet,
};