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9200514ad8
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.
329 lines
11 KiB
C
329 lines
11 KiB
C
/*
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* NuppelVideo demuxer.
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* Copyright (c) 2006 Reimar Doeffinger
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "libavutil/channel_layout.h"
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#include "libavutil/imgutils.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/intfloat.h"
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#include "avformat.h"
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#include "internal.h"
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#include "riff.h"
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static const AVCodecTag nuv_audio_tags[] = {
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{ AV_CODEC_ID_PCM_S16LE, MKTAG('R', 'A', 'W', 'A') },
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{ AV_CODEC_ID_MP3, MKTAG('L', 'A', 'M', 'E') },
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{ AV_CODEC_ID_NONE, 0 },
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};
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typedef struct NUVContext {
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int v_id;
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int a_id;
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int rtjpg_video;
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} NUVContext;
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typedef enum {
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NUV_VIDEO = 'V',
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NUV_EXTRADATA = 'D',
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NUV_AUDIO = 'A',
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NUV_SEEKP = 'R',
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NUV_MYTHEXT = 'X'
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} nuv_frametype;
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static int nuv_probe(AVProbeData *p)
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{
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if (!memcmp(p->buf, "NuppelVideo", 12))
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return AVPROBE_SCORE_MAX;
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if (!memcmp(p->buf, "MythTVVideo", 12))
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return AVPROBE_SCORE_MAX;
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return 0;
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}
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/// little macro to sanitize packet size
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#define PKTSIZE(s) (s & 0xffffff)
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/**
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* @brief read until we found all data needed for decoding
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* @param vst video stream of which to change parameters
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* @param ast video stream of which to change parameters
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* @param myth set if this is a MythTVVideo format file
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* @return 0 or AVERROR code
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*/
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static int get_codec_data(AVIOContext *pb, AVStream *vst,
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AVStream *ast, int myth)
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{
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nuv_frametype frametype;
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if (!vst && !myth)
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return 1; // no codec data needed
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while (!pb->eof_reached) {
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int size, subtype;
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frametype = avio_r8(pb);
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switch (frametype) {
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case NUV_EXTRADATA:
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subtype = avio_r8(pb);
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avio_skip(pb, 6);
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size = PKTSIZE(avio_rl32(pb));
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if (vst && subtype == 'R') {
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if (vst->codecpar->extradata) {
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av_freep(&vst->codecpar->extradata);
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vst->codecpar->extradata_size = 0;
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}
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vst->codecpar->extradata = av_malloc(size);
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if (!vst->codecpar->extradata)
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return AVERROR(ENOMEM);
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vst->codecpar->extradata_size = size;
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avio_read(pb, vst->codecpar->extradata, size);
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size = 0;
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if (!myth)
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return 0;
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}
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break;
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case NUV_MYTHEXT:
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avio_skip(pb, 7);
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size = PKTSIZE(avio_rl32(pb));
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if (size != 128 * 4)
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break;
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avio_rl32(pb); // version
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if (vst) {
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vst->codecpar->codec_tag = avio_rl32(pb);
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vst->codecpar->codec_id =
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ff_codec_get_id(ff_codec_bmp_tags, vst->codecpar->codec_tag);
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if (vst->codecpar->codec_tag == MKTAG('R', 'J', 'P', 'G'))
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vst->codecpar->codec_id = AV_CODEC_ID_NUV;
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} else
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avio_skip(pb, 4);
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if (ast) {
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int id;
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ast->codecpar->codec_tag = avio_rl32(pb);
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ast->codecpar->sample_rate = avio_rl32(pb);
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ast->codecpar->bits_per_coded_sample = avio_rl32(pb);
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ast->codecpar->channels = avio_rl32(pb);
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ast->codecpar->channel_layout = 0;
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id = ff_wav_codec_get_id(ast->codecpar->codec_tag,
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ast->codecpar->bits_per_coded_sample);
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if (id == AV_CODEC_ID_NONE) {
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id = ff_codec_get_id(nuv_audio_tags, ast->codecpar->codec_tag);
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if (id == AV_CODEC_ID_PCM_S16LE)
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id = ff_get_pcm_codec_id(ast->codecpar->bits_per_coded_sample,
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0, 0, ~1);
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}
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ast->codecpar->codec_id = id;
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ast->need_parsing = AVSTREAM_PARSE_FULL;
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} else
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avio_skip(pb, 4 * 4);
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size -= 6 * 4;
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avio_skip(pb, size);
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return 0;
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case NUV_SEEKP:
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size = 11;
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break;
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default:
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avio_skip(pb, 7);
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size = PKTSIZE(avio_rl32(pb));
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break;
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}
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avio_skip(pb, size);
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}
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return 0;
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}
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static int nuv_header(AVFormatContext *s)
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{
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NUVContext *ctx = s->priv_data;
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AVIOContext *pb = s->pb;
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char id_string[12];
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double aspect, fps;
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int is_mythtv, width, height, v_packs, a_packs, ret;
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AVStream *vst = NULL, *ast = NULL;
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avio_read(pb, id_string, 12);
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is_mythtv = !memcmp(id_string, "MythTVVideo", 12);
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avio_skip(pb, 5); // version string
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avio_skip(pb, 3); // padding
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width = avio_rl32(pb);
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height = avio_rl32(pb);
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avio_rl32(pb); // unused, "desiredwidth"
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avio_rl32(pb); // unused, "desiredheight"
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avio_r8(pb); // 'P' == progressive, 'I' == interlaced
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avio_skip(pb, 3); // padding
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aspect = av_int2double(avio_rl64(pb));
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if (aspect > 0.9999 && aspect < 1.0001)
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aspect = 4.0 / 3.0;
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fps = av_int2double(avio_rl64(pb));
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if (fps < 0.0f) {
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if (s->error_recognition & AV_EF_EXPLODE) {
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av_log(s, AV_LOG_ERROR, "Invalid frame rate %f\n", fps);
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return AVERROR_INVALIDDATA;
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} else {
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av_log(s, AV_LOG_WARNING, "Invalid frame rate %f, setting to 0.\n", fps);
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fps = 0.0f;
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}
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}
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// number of packets per stream type, -1 means unknown, e.g. streaming
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v_packs = avio_rl32(pb);
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a_packs = avio_rl32(pb);
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avio_rl32(pb); // text
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avio_rl32(pb); // keyframe distance (?)
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if (v_packs) {
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vst = avformat_new_stream(s, NULL);
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if (!vst)
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return AVERROR(ENOMEM);
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ctx->v_id = vst->index;
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ret = av_image_check_size(width, height, 0, ctx);
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if (ret < 0)
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return ret;
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vst->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
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vst->codecpar->codec_id = AV_CODEC_ID_NUV;
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vst->codecpar->width = width;
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vst->codecpar->height = height;
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vst->codecpar->bits_per_coded_sample = 10;
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vst->sample_aspect_ratio = av_d2q(aspect * height / width,
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10000);
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vst->avg_frame_rate = av_d2q(fps, 60000);
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avpriv_set_pts_info(vst, 32, 1, 1000);
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} else
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ctx->v_id = -1;
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if (a_packs) {
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ast = avformat_new_stream(s, NULL);
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if (!ast)
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return AVERROR(ENOMEM);
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ctx->a_id = ast->index;
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ast->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
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ast->codecpar->codec_id = AV_CODEC_ID_PCM_S16LE;
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ast->codecpar->channels = 2;
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ast->codecpar->channel_layout = AV_CH_LAYOUT_STEREO;
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ast->codecpar->sample_rate = 44100;
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ast->codecpar->bit_rate = 2 * 2 * 44100 * 8;
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ast->codecpar->block_align = 2 * 2;
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ast->codecpar->bits_per_coded_sample = 16;
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avpriv_set_pts_info(ast, 32, 1, 1000);
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} else
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ctx->a_id = -1;
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if ((ret = get_codec_data(pb, vst, ast, is_mythtv)) < 0)
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return ret;
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ctx->rtjpg_video = vst && vst->codecpar->codec_id == AV_CODEC_ID_NUV;
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return 0;
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}
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#define HDRSIZE 12
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static int nuv_packet(AVFormatContext *s, AVPacket *pkt)
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{
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NUVContext *ctx = s->priv_data;
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AVIOContext *pb = s->pb;
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uint8_t hdr[HDRSIZE];
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nuv_frametype frametype;
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int ret, size;
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while (!pb->eof_reached) {
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int copyhdrsize = ctx->rtjpg_video ? HDRSIZE : 0;
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uint64_t pos = avio_tell(pb);
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ret = avio_read(pb, hdr, HDRSIZE);
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if (ret < HDRSIZE)
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return ret < 0 ? ret : AVERROR(EIO);
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frametype = hdr[0];
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size = PKTSIZE(AV_RL32(&hdr[8]));
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switch (frametype) {
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case NUV_EXTRADATA:
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if (!ctx->rtjpg_video) {
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avio_skip(pb, size);
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break;
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}
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case NUV_VIDEO:
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if (ctx->v_id < 0) {
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av_log(s, AV_LOG_ERROR, "Video packet in file without video stream!\n");
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avio_skip(pb, size);
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break;
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}
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ret = av_new_packet(pkt, copyhdrsize + size);
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if (ret < 0)
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return ret;
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// HACK: we have no idea if it is a keyframe,
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// but if we mark none seeking will not work at all.
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pkt->flags |= AV_PKT_FLAG_KEY;
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pkt->pos = pos;
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pkt->pts = AV_RL32(&hdr[4]);
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pkt->stream_index = ctx->v_id;
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memcpy(pkt->data, hdr, copyhdrsize);
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ret = avio_read(pb, pkt->data + copyhdrsize, size);
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if (ret < 0) {
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av_packet_unref(pkt);
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return ret;
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}
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if (ret < size)
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av_shrink_packet(pkt, copyhdrsize + ret);
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return 0;
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case NUV_AUDIO:
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if (ctx->a_id < 0) {
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av_log(s, AV_LOG_ERROR, "Audio packet in file without audio stream!\n");
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avio_skip(pb, size);
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break;
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}
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ret = av_get_packet(pb, pkt, size);
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pkt->flags |= AV_PKT_FLAG_KEY;
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pkt->pos = pos;
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pkt->pts = AV_RL32(&hdr[4]);
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pkt->stream_index = ctx->a_id;
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if (ret < 0)
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return ret;
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return 0;
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case NUV_SEEKP:
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// contains no data, size value is invalid
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break;
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default:
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avio_skip(pb, size);
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break;
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}
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}
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return AVERROR(EIO);
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}
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AVInputFormat ff_nuv_demuxer = {
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.name = "nuv",
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.long_name = NULL_IF_CONFIG_SMALL("NuppelVideo"),
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.priv_data_size = sizeof(NUVContext),
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.read_probe = nuv_probe,
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.read_header = nuv_header,
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.read_packet = nuv_packet,
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.flags = AVFMT_GENERIC_INDEX,
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};
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