a64.c
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1 /*
2  * a64 muxer
3  * Copyright (c) 2009 Tobias Bindhammer
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 
22 #include "libavcodec/avcodec.h"
23 #include "libavcodec/bytestream.h"
24 #include "avformat.h"
25 #include "rawenc.h"
26 
27 static int a64_write_header(struct AVFormatContext *s)
28 {
29  AVCodecContext *avctx = s->streams[0]->codec;
30  uint8_t header[5] = {
31  0x00, //load
32  0x40, //address
33  0x00, //mode
34  0x00, //charset_lifetime (multi only)
35  0x00 //fps in 50/fps;
36  };
37  switch (avctx->codec->id) {
39  header[2] = 0x00;
40  header[3] = AV_RB32(avctx->extradata+0);
41  header[4] = 2;
42  break;
44  header[2] = 0x01;
45  header[3] = AV_RB32(avctx->extradata+0);
46  header[4] = 3;
47  break;
48  default:
49  return AVERROR(EINVAL);
50  }
51  avio_write(s->pb, header, 2);
52  return 0;
53 }
54 
56  .name = "a64",
57  .long_name = NULL_IF_CONFIG_SMALL("a64 - video for Commodore 64"),
58  .extensions = "a64, A64",
59  .video_codec = AV_CODEC_ID_A64_MULTI,
60  .write_header = a64_write_header,
61  .write_packet = ff_raw_write_packet,
62 };
const struct AVCodec * codec
const char * s
Definition: avisynth_c.h:668
AVOutputFormat ff_a64_muxer
Definition: a64.c:55
Format I/O context.
Definition: avformat.h:944
uint8_t
#define AV_RB32
static int a64_write_header(struct AVFormatContext *s)
Definition: a64.c:27
uint8_t * extradata
some codecs need / can use extradata like Huffman tables.
AVStream ** streams
Definition: avformat.h:992
void avio_write(AVIOContext *s, const unsigned char *buf, int size)
Definition: aviobuf.c:173
enum AVCodecID id
#define NULL_IF_CONFIG_SMALL(x)
Return NULL if CONFIG_SMALL is true, otherwise the argument without modification. ...
external API header
AVCodecContext * codec
Codec context associated with this stream.
Definition: avformat.h:662
const char * name
Definition: avformat.h:378
int ff_raw_write_packet(AVFormatContext *s, AVPacket *pkt)
AVIOContext * pb
I/O context.
Definition: avformat.h:977
main external API structure.
Filter the word “frame” indicates either a video frame or a group of audio as stored in an AVFilterBuffer structure Format for each input and each output the list of supported formats For video that means pixel format For audio that means channel sample they are references to shared objects When the negotiation mechanism computes the intersection of the formats supported at each end of a all references to both lists are replaced with a reference to the intersection And when a single format is eventually chosen for a link amongst the remaining all references to the list are updated That means that if a filter requires that its input and output have the same format amongst a supported all it has to do is use a reference to the same list of formats query_formats can leave some formats unset and return AVERROR(EAGAIN) to cause the negotiation mechanism toagain later.That can be used by filters with complex requirements to use the format negotiated on one link to set the formats supported on another.Buffer references ownership and permissions
Main libavformat public API header.