FFmpeg/libavformat/yuv4mpegenc.c
Anton Khirnov 9200514ad8 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.
2016-02-23 17:01:58 +01:00

189 lines
6.0 KiB
C

/*
* YUV4MPEG muxer
* Copyright (c) 2001, 2002, 2003 Fabrice Bellard
*
* 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
*/
#include "libavutil/pixdesc.h"
#include "avformat.h"
#include "internal.h"
#include "yuv4mpeg.h"
#define Y4M_LINE_MAX 256
static int yuv4_generate_header(AVFormatContext *s, char* buf)
{
AVStream *st;
int width, height;
int raten, rated, aspectn, aspectd, n;
char inter;
const char *colorspace = "";
st = s->streams[0];
width = st->codecpar->width;
height = st->codecpar->height;
// TODO: should be avg_frame_rate
av_reduce(&raten, &rated, st->time_base.den,
st->time_base.num, (1UL << 31) - 1);
aspectn = st->sample_aspect_ratio.num;
aspectd = st->sample_aspect_ratio.den;
if (aspectn == 0 && aspectd == 1)
aspectd = 0; // 0:0 means unknown
switch (st->codecpar->field_order) {
case AV_FIELD_TT: inter = 't'; break;
case AV_FIELD_BB: inter = 'b'; break;
default: inter = 'p'; break;
}
switch (st->codecpar->format) {
case AV_PIX_FMT_GRAY8:
colorspace = " Cmono";
break;
case AV_PIX_FMT_YUV411P:
colorspace = " C411 XYSCSS=411";
break;
case AV_PIX_FMT_YUV420P:
switch (st->codecpar->chroma_location) {
case AVCHROMA_LOC_TOPLEFT: colorspace = " C420paldv XYSCSS=420PALDV"; break;
case AVCHROMA_LOC_LEFT: colorspace = " C420mpeg2 XYSCSS=420MPEG2"; break;
default: colorspace = " C420jpeg XYSCSS=420JPEG"; break;
}
break;
case AV_PIX_FMT_YUV422P:
colorspace = " C422 XYSCSS=422";
break;
case AV_PIX_FMT_YUV444P:
colorspace = " C444 XYSCSS=444";
break;
}
/* construct stream header, if this is the first frame */
n = snprintf(buf, Y4M_LINE_MAX, "%s W%d H%d F%d:%d I%c A%d:%d%s\n",
Y4M_MAGIC, width, height, raten, rated, inter,
aspectn, aspectd, colorspace);
return n;
}
static int yuv4_write_packet(AVFormatContext *s, AVPacket *pkt)
{
AVStream *st = s->streams[pkt->stream_index];
AVIOContext *pb = s->pb;
AVFrame *frame;
int* first_pkt = s->priv_data;
int width, height, h_chroma_shift, v_chroma_shift;
int i;
char buf2[Y4M_LINE_MAX + 1];
char buf1[20];
uint8_t *ptr, *ptr1, *ptr2;
frame = (AVFrame *)pkt->data;
/* for the first packet we have to output the header as well */
if (*first_pkt) {
*first_pkt = 0;
if (yuv4_generate_header(s, buf2) < 0) {
av_log(s, AV_LOG_ERROR,
"Error. YUV4MPEG stream header write failed.\n");
return AVERROR(EIO);
} else {
avio_write(pb, buf2, strlen(buf2));
}
}
/* construct frame header */
snprintf(buf1, sizeof(buf1), "%s\n", Y4M_FRAME_MAGIC);
avio_write(pb, buf1, strlen(buf1));
width = st->codecpar->width;
height = st->codecpar->height;
ptr = frame->data[0];
for (i = 0; i < height; i++) {
avio_write(pb, ptr, width);
ptr += frame->linesize[0];
}
if (st->codecpar->format != AV_PIX_FMT_GRAY8) {
// Adjust for smaller Cb and Cr planes
av_pix_fmt_get_chroma_sub_sample(st->codecpar->format, &h_chroma_shift,
&v_chroma_shift);
// Shift right, rounding up
width = AV_CEIL_RSHIFT(width, h_chroma_shift);
height = AV_CEIL_RSHIFT(height, v_chroma_shift);
ptr1 = frame->data[1];
ptr2 = frame->data[2];
for (i = 0; i < height; i++) { /* Cb */
avio_write(pb, ptr1, width);
ptr1 += frame->linesize[1];
}
for (i = 0; i < height; i++) { /* Cr */
avio_write(pb, ptr2, width);
ptr2 += frame->linesize[2];
}
}
return 0;
}
static int yuv4_write_header(AVFormatContext *s)
{
int *first_pkt = s->priv_data;
if (s->nb_streams != 1)
return AVERROR(EIO);
if (s->streams[0]->codecpar->codec_id != AV_CODEC_ID_WRAPPED_AVFRAME) {
av_log(s, AV_LOG_ERROR, "ERROR: Codec not supported.\n");
return AVERROR_INVALIDDATA;
}
if (s->streams[0]->codecpar->format == AV_PIX_FMT_YUV411P) {
av_log(s, AV_LOG_ERROR, "Warning: generating rarely used 4:1:1 YUV "
"stream, some mjpegtools might not work.\n");
} else if ((s->streams[0]->codecpar->format != AV_PIX_FMT_YUV420P) &&
(s->streams[0]->codecpar->format != AV_PIX_FMT_YUV422P) &&
(s->streams[0]->codecpar->format != AV_PIX_FMT_GRAY8) &&
(s->streams[0]->codecpar->format != AV_PIX_FMT_YUV444P)) {
av_log(s, AV_LOG_ERROR, "ERROR: yuv4mpeg only handles yuv444p, "
"yuv422p, yuv420p, yuv411p and gray pixel formats. "
"Use -pix_fmt to select one.\n");
return AVERROR(EIO);
}
*first_pkt = 1;
return 0;
}
AVOutputFormat ff_yuv4mpegpipe_muxer = {
.name = "yuv4mpegpipe",
.long_name = NULL_IF_CONFIG_SMALL("YUV4MPEG pipe"),
.mime_type = "",
.extensions = "y4m",
.priv_data_size = sizeof(int),
.audio_codec = AV_CODEC_ID_NONE,
.video_codec = AV_CODEC_ID_WRAPPED_AVFRAME,
.write_header = yuv4_write_header,
.write_packet = yuv4_write_packet,
};