From 96a45a16af5594900ca94e7d4abb18d1e6d5ed4a Mon Sep 17 00:00:00 2001 From: wm4 Date: Tue, 7 Feb 2017 17:05:17 +0100 Subject: player: add experimental stream recording feature This is basically a WIP, but it can't remain in a branch forever. A warning is print when using it as it's still a bit "shaky". --- common/recorder.c | 384 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ common/recorder.h | 21 +++ 2 files changed, 405 insertions(+) create mode 100644 common/recorder.c create mode 100644 common/recorder.h (limited to 'common') diff --git a/common/recorder.c b/common/recorder.c new file mode 100644 index 0000000000..d8f937b902 --- /dev/null +++ b/common/recorder.c @@ -0,0 +1,384 @@ +/* + * This file is part of mpv. + * + * mpv 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. + * + * mpv 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 mpv. If not, see . + */ + +#include + +#include + +#include "common/av_common.h" +#include "common/common.h" +#include "common/global.h" +#include "common/msg.h" +#include "demux/packet.h" +#include "demux/stheader.h" + +#include "recorder.h" + +#define PTS_ADD(a, b) ((a) == MP_NOPTS_VALUE ? (a) : ((a) + (b))) + +// Maximum number of packets we buffer at most to attempt to resync streams. +// Essentially, this should be higher than the highest supported keyframe +// interval. +#define QUEUE_MAX_PACKETS 256 +// Number of packets we should buffer at least to determine timestamps (due to +// codec delay and frame reordering, and potentially lack of DTS). +// Keyframe flags can trigger this earlier. +#define QUEUE_MIN_PACKETS 16 + +struct mp_recorder { + struct mpv_global *global; + struct mp_log *log; + + struct mp_recorder_sink **streams; + int num_streams; + + bool opened; // mux context is valid + bool muxing; // we're currently recording (instead of preparing) + bool muxing_from_start; // no discontinuity at start + bool dts_warning; + + // The start timestamp of the currently recorded segment (the timestamp of + // the first packet of the incoming packet stream). + double base_ts; + // The output packet timestamp corresponding to base_ts. It's the timestamp + // of the first packet of the current segment written to the output. + double rebase_ts; + + AVFormatContext *mux; +}; + +struct mp_recorder_sink { + struct mp_recorder *owner; + struct sh_stream *sh; + AVStream *av_stream; + double max_out_pts; + bool discont; + bool proper_eof; + struct demux_packet **packets; + int num_packets; +}; + +static int add_stream(struct mp_recorder *priv, struct sh_stream *sh) +{ + enum AVMediaType av_type = mp_to_av_stream_type(sh->type); + if (av_type == AVMEDIA_TYPE_UNKNOWN) + return -1; + + struct mp_recorder_sink *rst = talloc(priv, struct mp_recorder_sink); + *rst = (struct mp_recorder_sink) { + .owner = priv, + .sh = sh, + .av_stream = avformat_new_stream(priv->mux, NULL), + .max_out_pts = MP_NOPTS_VALUE, + }; + + if (!rst->av_stream) + return -1; + + AVCodecParameters *avp = mp_codec_params_to_av(sh->codec); + if (!avp) + return -1; + +#if LIBAVCODEC_VERSION_MICRO >= 100 + // We don't know the delay, so make something up. If the format requires + // DTS, the result will probably be broken. FFmpeg provides nothing better + // yet (unless you demux with libavformat, which contains tons of hacks + // that try to determine a PTS). + if (!sh->codec->lav_codecpar) + avp->video_delay = 16; +#endif + + if (avp->codec_id == AV_CODEC_ID_NONE) + return -1; + + if (avcodec_parameters_copy(rst->av_stream->codecpar, avp) < 0) + return -1; + + rst->av_stream->time_base = mp_get_codec_timebase(sh->codec); + + MP_TARRAY_APPEND(priv, priv->streams, priv->num_streams, rst); + return 0; +} + +struct mp_recorder *mp_recorder_create(struct mpv_global *global, + const char *target_file, + struct sh_stream **streams, + int num_streams) +{ + struct mp_recorder *priv = talloc_zero(NULL, struct mp_recorder); + + priv->global = global; + priv->log = mp_log_new(priv, global->log, "recorder"); + + if (!num_streams) { + MP_ERR(priv, "No streams.\n"); + goto error; + } + + priv->mux = avformat_alloc_context(); + if (!priv->mux) + goto error; + + priv->mux->oformat = av_guess_format(NULL, target_file, NULL); + if (!priv->mux->oformat) { + MP_ERR(priv, "Output format not found.\n"); + goto error; + } + + if (avio_open2(&priv->mux->pb, target_file, AVIO_FLAG_WRITE, NULL, NULL) < 0) { + MP_ERR(priv, "Failed opening output file.\n"); + goto error; + } + + for (int n = 0; n < num_streams; n++) { + if (add_stream(priv, streams[n]) < 0) { + MP_ERR(priv, "Can't mux one of the input streams.\n"); + goto error; + } + } + + // Not sure how to write this in a "standard" way. It appears only mkv + // and mp4 support this directly. + char version[200]; + snprintf(version, sizeof(version), "%s experimental stream recording " + "feature (can generate broken files - please report bugs)", + mpv_version); + av_dict_set(&priv->mux->metadata, "encoding_tool", version, 0); + + if (avformat_write_header(priv->mux, NULL) < 0) { + MP_ERR(priv, "Write header failed.\n"); + goto error; + } + + priv->opened = true; + priv->muxing_from_start = true; + + priv->base_ts = MP_NOPTS_VALUE; + priv->rebase_ts = 0; + + MP_WARN(priv, "This is an experimental feature. Output files might be " + "broken or not play correctly with various players " + "(including mpv itself).\n"); + + return priv; + +error: + mp_recorder_destroy(priv); + return NULL; +} + +static void flush_packets(struct mp_recorder *priv) +{ + for (int n = 0; n < priv->num_streams; n++) { + struct mp_recorder_sink *rst = priv->streams[n]; + for (int i = 0; i < rst->num_packets; i++) + talloc_free(rst->packets[i]); + rst->num_packets = 0; + } +} + +static void mux_packet(struct mp_recorder_sink *rst, + struct demux_packet *pkt) +{ + struct mp_recorder *priv = rst->owner; + struct demux_packet mpkt = *pkt; + + double diff = priv->rebase_ts - priv->base_ts; + mpkt.pts = PTS_ADD(mpkt.pts, diff); + mpkt.dts = PTS_ADD(mpkt.dts, diff); + + rst->max_out_pts = MPMAX(rst->max_out_pts, pkt->pts); + + AVPacket avpkt; + mp_set_av_packet(&avpkt, &mpkt, &rst->av_stream->time_base); + + avpkt.stream_index = rst->av_stream->index; + + if (avpkt.duration < 0 && rst->sh->type != STREAM_SUB) + avpkt.duration = 0; + + AVPacket *new_packet = av_packet_clone(&avpkt); + if (!new_packet) { + MP_ERR(priv, "Failed to allocate packet.\n"); + return; + } + + if (av_interleaved_write_frame(priv->mux, new_packet) < 0) + MP_ERR(priv, "Failed writing packet.\n"); +} + +// Write all packets that currently can be written. +static void mux_packets(struct mp_recorder_sink *rst, bool force) +{ + struct mp_recorder *priv = rst->owner; + if (!priv->muxing || !rst->num_packets) + return; + + int safe_count = 0; + for (int n = 0; n < rst->num_packets; n++) { + if (rst->packets[n]->keyframe) + safe_count = n; + } + if (force) + safe_count = rst->num_packets; + + for (int n = 0; n < safe_count; n++) { + mux_packet(rst, rst->packets[n]); + talloc_free(rst->packets[n]); + } + + // Remove packets[0..safe_count] + memmove(&rst->packets[0], &rst->packets[safe_count], + (rst->num_packets - safe_count) * sizeof(rst->packets[0])); + rst->num_packets -= safe_count; +} + +// If there was a discontinuity, check whether we can resume muxing (and from +// where). +static void check_restart(struct mp_recorder *priv) +{ + if (priv->muxing) + return; + + double min_ts = INFINITY; + double rebase_ts = 0; + for (int n = 0; n < priv->num_streams; n++) { + struct mp_recorder_sink *rst = priv->streams[n]; + int min_packets = rst->sh->type == STREAM_VIDEO ? QUEUE_MIN_PACKETS : 1; + + rebase_ts = MPMAX(rebase_ts, rst->max_out_pts); + + if (rst->num_packets < min_packets) { + if (!rst->proper_eof && rst->sh->type != STREAM_SUB) + return; + continue; + } + + for (int i = 0; i < min_packets; i++) + min_ts = MPMIN(min_ts, rst->packets[i]->pts); + } + + // Subtitle only stream (wait longer) or stream without any PTS (fuck it). + if (!isfinite(min_ts)) + return; + + priv->rebase_ts = rebase_ts; + priv->base_ts = min_ts; + + for (int n = 0; n < priv->num_streams; n++) { + struct mp_recorder_sink *rst = priv->streams[n]; + rst->max_out_pts = min_ts; + } + + priv->muxing = true; + + if (!priv->muxing_from_start) + MP_WARN(priv, "Discontinuity at timestamp %f.\n", priv->rebase_ts); +} + +void mp_recorder_destroy(struct mp_recorder *priv) +{ + if (priv->opened) { + for (int n = 0; n < priv->num_streams; n++) { + struct mp_recorder_sink *rst = priv->streams[n]; + if (!rst->proper_eof) + continue; + mux_packets(rst, true); + } + + if (av_write_trailer(priv->mux) < 0) + MP_ERR(priv, "Writing trailer failed.\n"); + } + + if (priv->mux) { + if (avio_closep(&priv->mux->pb) < 0) + MP_ERR(priv, "Closing file failed\n"); + + avformat_free_context(priv->mux); + } + + flush_packets(priv); + talloc_free(priv); +} + +// This is called on a seek, or when recording was started mid-stream. +void mp_recorder_mark_discontinuity(struct mp_recorder *priv) +{ + flush_packets(priv); + + for (int n = 0; n < priv->num_streams; n++) { + struct mp_recorder_sink *rst = priv->streams[n]; + rst->discont = true; + rst->proper_eof = false; + } + + priv->muxing = false; + priv->muxing_from_start = false; +} + +// Get a stream for writing. The pointer is valid until mp_recorder is +// destroyed. The stream is the index referencing the stream passed to +// mp_recorder_create(). +struct mp_recorder_sink *mp_recorder_get_sink(struct mp_recorder *r, int stream) +{ + assert(stream >= 0 && stream < r->num_streams); + return r->streams[stream]; +} + +// Pass a packet to the given stream. The function does not own the packet, but +// can create a new reference to it if it needs to retain it. Can be NULL to +// signal proper end of stream. +void mp_recorder_feed_packet(struct mp_recorder_sink *rst, + struct demux_packet *pkt) +{ + struct mp_recorder *priv = rst->owner; + + if (!pkt) { + rst->proper_eof = true; + check_restart(priv); + mux_packets(rst, false); + return; + } + + if (pkt->dts == MP_NOPTS_VALUE && !priv->dts_warning) { + // No, FFmpeg has no actually usable helpers to generate correct DTS. + // No, FFmpeg doesn't tell us which formats need DTS at all. + // No, we can not shut up the FFmpeg warning, which will follow. + MP_WARN(priv, "Source stream misses DTS on at least some packets!\n" + "If the target file format requires DTS, the written\n" + "file will be invalid.\n"); + priv->dts_warning = true; + } + + if (rst->discont && !pkt->keyframe) + return; + rst->discont = false; + + if (rst->num_packets >= QUEUE_MAX_PACKETS) { + MP_ERR(priv, "Stream %d has too many queued packets; dropping.\n", + rst->av_stream->index); + return; + } + + pkt = demux_copy_packet(pkt); + if (!pkt) + return; + MP_TARRAY_APPEND(rst, rst->packets, rst->num_packets, pkt); + + check_restart(priv); + mux_packets(rst, false); +} diff --git a/common/recorder.h b/common/recorder.h new file mode 100644 index 0000000000..a6c8635c01 --- /dev/null +++ b/common/recorder.h @@ -0,0 +1,21 @@ +#ifndef MP_RECORDER_H_ +#define MP_RECORDER_H_ + +struct mp_recorder; +struct mpv_global; +struct demux_packet; +struct sh_stream; +struct mp_recorder_sink; + +struct mp_recorder *mp_recorder_create(struct mpv_global *global, + const char *target_file, + struct sh_stream **streams, + int num_streams); +void mp_recorder_destroy(struct mp_recorder *r); +void mp_recorder_mark_discontinuity(struct mp_recorder *r); + +struct mp_recorder_sink *mp_recorder_get_sink(struct mp_recorder *r, int stream); +void mp_recorder_feed_packet(struct mp_recorder_sink *s, + struct demux_packet *pkt); + +#endif -- cgit v1.2.3